<system_instruction>
You are working inside Conductor, a Mac app that lets the user run many coding agents in parallel.
Your work should take place in the /Users/noah/conductor/workspaces/deadca7/san-diego directory (unless otherwise directed), which has been set up for you to work in.
Each workspace has a .context directory (gitignored) where you can save files to collaborate with other agents.
The target branch for this workspace is origin/main. Use this for actions like diffing (`git diff origin/main...`) or creating PRs (`gh pr create --base main`).

Do not rename the current branch unless the user explicitly tells you to do so.

By default, the user will only see the last message that you send before stopping. Include all essential information in the last message. The intermediate messages will be collapsed and accessible by the user but not displayed by default.

If the user asks you to work on several unrelated tasks, you can suggest they start new workspaces.
Sometimes the user might send you a message they meant to send in a different workspace or a different chat. If something doesn't make sense in the context of your work, just ask.
If the user asks for help with Conductor, you can ask them to go to "Help -> Send Feedback" to get in touch with our team.
</system_instruction>

help plan, what ever is in link/ is in the wrong place. if used, move that to app.

link is going to be a port of pioneer pro link integration to go

https://github.com/Deep-Symmetry/beat-link
https://github.com/Deep-Symmetry/crate-digger

We've started that port in https://github.com/nzoschke/vizlab/tree/main/pkg/link

but its not reliable so I think we want to build some tests first by documenting how then performing packet captures from our CDJ-3000


- total-recall: Contextify Total Recall - Search past conversations and decisions with your AI. https://contextify.sh
- create-collection: Create or assemble a deadca7 music collection. Use when the user wants to import a collection from an Internet Archive URL ("create a collection from https://archive.org/details/..."), or to build/edit a collection, playlists, or tracks by hand. Drives the deadca7 CLI against the running catalog API.
- deep-research: Deep research harness — fan-out web searches, fetch sources, adversarially verify claims, synthesize a cited report. - When the user wants a deep, multi-source, fact-checked research report on any topic. BEFORE invoking, check if the question is specific enough to research directly — if underspecified (e.g., "what car to buy" without budget/use-case/region), ask 2-3 clarifying questions to narrow scope. Then pass the refined question as args, weaving the answers in.
- conductor:conductor: Build, configure, and troubleshoot Conductor workspaces, project setup recommendations, repository scripts, conductor.json, managed settings, files to copy, MCP, agent controls, and review workflows. Use when helping someone set up or operate Conductor.
- update-config: Use this skill to configure the Claude Code harness via settings.json. Automated behaviors ("from now on when X", "each time X", "whenever X", "before/after X") require hooks configured in settings.json - the harness executes these, not Claude, so memory/preferences cannot fulfill them. Also use for: permissions ("allow X", "add permission", "move permission to"), env vars ("set X=Y"), hook troubleshooting, or any changes to settings.json/settings.local.json files. Examples: "allow npm commands", "add bq permission to global settings", "move permission to user settings", "set DEBUG=true", "when claude stops show X". For simple settings like theme/model, suggest the /config command.
- keybindings-help: Use when the user wants to customize keyboard shortcuts, rebind keys, add chord bindings, or modify ~/.claude/keybindings.json. Examples: "rebind ctrl+s", "add a chord shortcut", "change the submit key", "customize keybindings".
- verify: Verify that a code change actually does what it's supposed to by running the app and observing behavior. Use when asked to verify a PR, confirm a fix works, test a change manually, check that a feature works, or validate local changes before pushing.
- code-review: Review the current diff for correctness bugs and reuse/simplification/efficiency cleanups at the given effort level (low/medium: fewer, high-confidence findings; high→max: broader coverage, may include uncertain findings; ultra: deep multi-agent review in the cloud). Pass --comment to post findings as inline PR comments, or --fix to apply the findings to the working tree after the review.
- simplify: Review the changed code for reuse, simplification, efficiency, and altitude cleanups, then apply the fixes. Quality only — it does not hunt for bugs; use /code-review for that.
- fewer-permission-prompts: Scan your transcripts for common read-only Bash and MCP tool calls, then add a prioritized allowlist to project .claude/settings.json to reduce permission prompts.
- loop: Run a prompt or slash command on a recurring interval (e.g. /loop 5m /foo, defaults to 10m) - When the user wants to set up a recurring task, poll for status, or run something repeatedly on an interval (e.g. "check the deploy every 5 minutes", "keep running /babysit-prs"). Do NOT invoke for one-off tasks.
- schedule: Create, update, list, or run scheduled remote agents (routines) that execute on a cron schedule. - When the user wants to schedule a recurring remote agent, set up automated tasks, create a cron job for Claude Code, or manage their scheduled agents/routines. Also use when the user wants a one-time scheduled run ("run this once at 3pm", "remind me to check X tomorrow").
- claude-api: Build, debug, and optimize Claude API / Anthropic SDK apps. Apps built with this skill should include prompt caching. Also handles migrating existing Claude API code between Claude model versions (4.5 → 4.6, 4.6 → 4.7, retired-model replacements).
TRIGGER when: code imports `anthropic`/`@anthropic-ai/sdk`; user asks for the Claude API, Anthropic SDK, or Managed Agents; user adds/modifies/tunes a Claude feature (caching, thinking, compaction, tool use, batch, files, citations, memory) or model (Opus/Sonnet/Haiku) in a file; questions about prompt caching / cache hit rate in an Anthropic SDK project.
SKIP: file imports `openai`/other-provider SDK, filename like `*-openai.py`/`*-generic.py`, provider-neutral code, general programming/ML.
- run: Launch and drive this project's app to see a change working. Use when asked to run, start, or screenshot the app, or to confirm a change works in the real app (not just tests). First looks for a project skill that already covers launching the app; otherwise falls back to built-in patterns per project type (CLI, server, TUI, Electron, browser-driven, library).
- init: Initialize a new CLAUDE.md file with codebase documentation
- review: Review a pull request
- security-review: Complete a security review of the pending changes on the current branch

total-recall create-collection deep-research conductor:conductor update-config keybindings-help verify code-review simplify fewer-permission-prompts loop schedule claude-api run init review security-review


Your organization has disabled Claude subscription access for Claude Code · Use an Anthropic API key instead, or ask your admin to enable access


try again


 So the user is working on porting Pioneer Pro Link integration to Go, starting with a `link/` directory that needs to be relocated to `app`. They've begun implementation in `vizlab/pkg/link` but it's unreliable, so they want to establish a solid test foundation first by documenting the testing approach and capturing packets from their CDJ-3000 to work with real data.

I should start by examining the current repository structure and the existing `link/` directory to understand what's already there and how it's organized.


I'll start by exploring the current state of the repo, especially the `link/` directory and the overall structure.


Bash

ls -la && echo "---LINK---" && find link -type f 2>/dev/null | head -50 && echo "---APP---" && ls -la app 2>/dev/null

Explore repo structure and link/ directory


total 112
drwxr-xr-x@ 14 noah  staff    448 Jun  7 08:12 .
drwxr-xr-x@  3 noah  staff     96 Jun  7 08:12 ..
drwxr-xr-x@  3 noah  staff     96 Jun  7 08:12 .claude
drwxr-xr-x@  3 noah  staff     96 Jun  7 08:12 .context
-rw-r--r--@  1 noah  staff     69 Jun  7 08:12 .git
-rw-r--r--@  1 noah  staff     62 Jun  7 08:12 .gitignore
-rw-r--r--@  1 noah  staff    606 Jun  7 08:12 CLAUDE.md
-rw-r--r--@  1 noah  staff    452 Jun  7 08:12 README.md
drwxr-xr-x@ 17 noah  staff    544 Jun  7 08:12 app
-rw-r--r--@  1 noah  staff     54 Jun  7 08:12 go.work
-rw-r--r--@  1 noah  staff  35265 Jun  7 08:12 go.work.sum
drwxr-xr-x@  5 noah  staff    160 Jun  7 08:12 link
drwxr-xr-x@  8 noah  staff    256 Jun  7 08:12 magefiles
drwxr-xr-x@ 15 noah  staff    480 Jun  7 08:12 www
---LINK---
link/go.mod
link/link_test.go
link/link.go
---APP---
total 120
drwxr-xr-x@ 17 noah  staff    544 Jun  7 08:12 .
drwxr-xr-x@ 14 noah  staff    448 Jun  7 08:12 ..
-rw-r--r--@  1 noah  staff     65 Jun  7 08:12 .gitignore
drwxr-xr-x@  6 noah  staff    192 Jun  7 08:12 analysis
drwxr-xr-x@  3 noah  staff     96 Jun  7 08:12 api
-rw-r--r--@  1 noah  staff    321 Jun  7 08:12 app.go
drwxr-xr-x@  5 noah  staff    160 Jun  7 08:12 cmd
drwxr-xr-x@  6 noah  staff    192 Jun  7 08:12 collection
drwxr-xr-x@ 11 noah  staff    352 Jun  7 08:12 db
drwxr-xr-x@  4 noah  staff    128 Jun  7 08:12 doc
drwxr-xr-x@  3 noah  staff     96 Jun  7 08:12 gen
-rw-r--r--@  1 noah  staff   6250 Jun  7 08:12 go.mod
-rw-r--r--@  1 noah  staff  42076 Jun  7 08:12 go.sum
drwxr-xr-x@  3 noah  staff     96 Jun  7 08:12 imports
drwxr-xr-x@  4 noah  staff    128 Jun  7 08:12 music
drwxr-xr-x@ 12 noah  staff    384 Jun  7 08:12 onelib
drwxr-xr-x@ 12 noah  staff    384 Jun  7 08:12 ui


I'll read the current `link/` code and understand the app structure, then look at the reference projects.


1	// Package link generates and resolves shareable catalog links.
2	package link
3
4	// New returns a shareable link for the given catalog item id.
5	func New(id string) string {
6		return "deadca7://item/" + id
7	}
8

// Package link generates and resolves shareable catalog links.
package link

// New returns a shareable link for the given catalog item id.
func New(id string) string {
	return "deadca7://item/" + id
}


1	package link
2
3	import "testing"
4
5	func TestNew(t *testing.T) {
6		if got, want := New("abc"), "deadca7://item/abc"; got != want {
7			t.Errorf("New(\"abc\") = %q, want %q", got, want)
8		}
9	}
10

package link

import "testing"

func TestNew(t *testing.T) {
	if got, want := New("abc"), "deadca7://item/abc"; got != want {
		t.Errorf("New(\"abc\") = %q, want %q", got, want)
	}
}


1	module github.com/nzoschke/deadca7/link
2
3	go 1.26.4
4

module github.com/nzoschke/deadca7/link

go 1.26.4


1	go 1.26.4
2
3	use (
4		./app
5		./link
6		./magefiles
7		./www
8	)
9

go 1.26.4

use (
	./app
	./link
	./magefiles
	./www
)


1	// Package app holds the core catalog logic for deadca7.
2	package app
3
4	import "github.com/nzoschke/deadca7/link"
5
6	// Item is a single audio/video entry in the catalog.
7	type Item struct {
8		ID    string
9		Title string
10	}
11
12	// Share returns a shareable link for the item.
13	func (i Item) Share() string {
14		return link.New(i.ID)
15	}
16

// Package app holds the core catalog logic for deadca7.
package app

import "github.com/nzoschke/deadca7/link"

// Item is a single audio/video entry in the catalog.
type Item struct {
	ID    string
	Title string
}

// Share returns a shareable link for the item.
func (i Item) Share() string {
	return link.New(i.ID)
}


 I see now — the `link/` directory is actually just a simple shareable catalog link generator, not the Pro DJ Link integration at all. The user wants to repurpose `link/` as the Pioneer Pro DJ Link network protocol implementation, which means the existing shareable link feature needs to move into the `app` directory since it's really about catalog item sharing.

Let me check how the link package is currently being used throughout the codebase to understand what needs to be refactored.


The picture is becoming clear. The existing `link/` package is a trivial catalog-link generator (`deadca7://item/abc`) — not the Pro DJ Link integration at all. The user wants `link/` to become the Pioneer Pro DJ Link port, so this existing code needs to move into `app`. Let me confirm usage across the codebase and check the reference repos.


echo "===magefiles===" && ls magefiles && echo "===www===" && ls www && echo "===app/cmd===" && find app/cmd -type f && echo "===README===" && cat README.md

Inspect magefiles, www, cmd, README


link/go.mod:1:module github.com/nzoschke/deadca7/link
app/app.go:4:import "github.com/nzoschke/deadca7/link"
app/app.go:14:	return link.New(i.ID)
app/go.mod:13:	github.com/nzoschke/deadca7/link v0.0.0
app/go.mod:129:replace github.com/nzoschke/deadca7/link => ../link


===magefiles===
app.go
deps.go
go.mod
go.sum
magefile.go
www.go
===www===
AGENTS.md
README.md
assets
cmd
content
docs
go.mod
go.sum
internal
static
===app/cmd===
app/cmd/deadca7/contents.go
app/cmd/deadca7/imports.go
app/cmd/deadca7/playlists.go
app/cmd/deadca7/collections.go
app/cmd/deadca7/flow_test.go
app/cmd/deadca7/artists.go
app/cmd/deadca7/main.go
app/cmd/deadca7/root.go
app/cmd/app/browser_test.go
app/cmd/app/main.go
app/cmd/app/audio.go
app/cmd/openapi/main.go
===README===
# deadca7

Dead Easy Audio / Video Catalog for DJs

## Development

```bash
brew install direnv golang
cp www/.envrc.example ../.envrc # move config outside of git worktree
direnv allow

go install github.com/magefile/mage@latest
mage deps          # install templ, tailwindcss, sqlc
mage www:dev       # run the web app on :8090 with hot reload
mage app:dev       # run the catalog app on :8091 with hot reload
```

Run `mage -l` to list all targets.


 I'm checking how `Item.Share()` is currently being used and realizing that `link/` is just a basic share-link generator right now, only called from `app.go`. The user wants to transform it into something much more substantial.

So the plan is: move the existing share-link code into the `app` package, then tackle the Pro DJ Link port by first documenting the protocol, capturing packets from actual CDJ-3000 hardware, building tests from those captures, and then porting the logic. The user mentioned the vizlab port is unreliable, so they want a test-first approach grounded in real protocol data.

I should look at the test structure in `flow_test.go` to match the existing style, and also examine what the vizlab port already has to understand the current state. Let me fetch those references to make the plan concrete.


The situation is clear. Let me look at the reference test structure mentioned in CLAUDE.md and gather the external context (the existing vizlab port and the Pro DJ Link protocol docs) before drafting a plan.


1	package main
2
3	import (
4		"bytes"
5		"encoding/json"
6		"net/http/httptest"
7		"path/filepath"
8		"testing"
9
10		"github.com/cockroachdb/errors"
11		"github.com/go-fuego/fuego"
12		"github.com/nzoschke/deadca7/app/api"
13		"github.com/nzoschke/deadca7/app/collection"
14		"github.com/nzoschke/deadca7/app/db"
15		"github.com/stretchr/testify/require"
16		_ "modernc.org/sqlite"
17	)
18
19	// run executes the CLI in-process against base, returning stdout and exit code.
20	func run(t *testing.T, base string, args ...string) (string, int) {
21		t.Helper()
22		root := newRoot()
23		out := &bytes.Buffer{}
24		root.SetOut(out)
25		root.SetErr(&bytes.Buffer{})
26		root.SetArgs(append([]string{"--base-url", base}, args...))
27
28		code := 0
29		if err := root.Execute(); err != nil {
30			code = exitAPI
31			var ee *exitError
32			if errors.As(err, &ee) {
33				code = ee.code
34			}
35		}
36		return out.String(), code
37	}
38
39	func id(t *testing.T, out string) string {
40		t.Helper()
41		var v struct {
42			ID int64 `json:"id"`
43		}
44		require.NoError(t, json.Unmarshal([]byte(out), &v))
45		require.NotZero(t, v.ID)
46		return itoa(v.ID)
47	}
48
49	func itoa(v int64) string {
50		b, _ := json.Marshal(v)
51		return string(b)
52	}
53
54	func TestFlow(t *testing.T) {
55		r := require.New(t)
56
57		sdb, err := db.Open(filepath.Join(t.TempDir(), "test.db"))
58		r.NoError(err)
59		defer sdb.Close()
60
61		s := fuego.NewServer(fuego.WithoutAutoGroupTags())
62		api.Register(s, collection.New(sdb), nil)
63		ts := httptest.NewServer(s.Mux)
64		defer ts.Close()
65
66		var collID, plID, cntID string
67
68		steps := []struct {
69			name   string
70			args   []string
71			code   int
72			assert func(t *testing.T, out string)
73		}{
74			{
75				name: "create collection",
76				args: []string{"collections", "create", "--name", "Live 77", "--slug", "live-77"},
77				assert: func(t *testing.T, out string) {
78					require.Contains(t, out, `"slug": "live-77"`)
79					collID = id(t, out)
80				},
81			},
82			{
83				name: "get collection",
84				args: []string{"collections", "get", ""},
85				assert: func(t *testing.T, out string) {
86					require.Contains(t, out, `"name": "Live 77"`)
87				},
88			},
89			{
90				name: "list collections",
91				args: []string{"collections", "list"},
92				assert: func(t *testing.T, out string) {
93					require.Contains(t, out, "live-77")
94				},
95			},
96			{
97				name: "create content",
98				args: []string{"contents", "create", "--title", "Scarlet Begonias", "--artist", "GD", "--track-no", "1"},
99				assert: func(t *testing.T, out string) {
100					require.Contains(t, out, "Scarlet Begonias")
101					cntID = id(t, out)
102				},
103			},
104			{
105				name: "create playlist",
106				args: []string{"playlists", "create", "--collection", "", "--name", "Set 1"},
107				assert: func(t *testing.T, out string) {
108					require.Contains(t, out, `"name": "Set 1"`)
109					plID = id(t, out)
110				},
111			},
112			{
113				name: "add content to playlist",
114				args: []string{"playlists", "add", "", "", "--seq", "0"},
115			},
116			{
117				name: "list playlist contents",
118				args: []string{"playlists", "contents", ""},
119				assert: func(t *testing.T, out string) {
120					require.Contains(t, out, "Scarlet Begonias")
121				},
122			},
123			{
124				name: "missing required flag is a usage error",
125				args: []string{"collections", "create", "--name", "no slug"},
126				code: exitUsage,
127			},
128			{
129				name: "not found is an api error",
130				args: []string{"collections", "get", "999999"},
131				code: exitAPI,
132			},
133			{
134				name: "delete collection",
135				args: []string{"collections", "delete", ""},
136			},
137		}
138
139		for _, tt := range steps {
140			t.Run(tt.name, func(t *testing.T) {
141				args := patch(tt.args, collID, plID, cntID)
142				out, code := run(t, ts.URL, args...)
143				require.Equal(t, tt.code, code, "out=%s", out)
144				if tt.assert != nil {
145					tt.assert(t, out)
146				}
147			})
148		}
149	}
150
151	// patch fills empty positional/flag slots with IDs captured from earlier steps,
152	// keeping the table readable without threading state through every row.
153	func patch(args []string, collID, plID, cntID string) []string {
154		out := append([]string(nil), args...)
155		switch {
156		case len(out) >= 3 && out[0] == "collections" && (out[1] == "get" || out[1] == "delete") && out[2] == "":
157			out[2] = collID
158		case len(out) >= 4 && out[0] == "playlists" && out[1] == "create":
159			out[3] = collID
160		case len(out) >= 4 && out[0] == "playlists" && out[1] == "add":
161			out[2], out[3] = plID, cntID
162		case len(out) >= 3 && out[0] == "playlists" && out[1] == "contents":
163			out[2] = plID
164		}
165		return out
166	}
167

package main

import (
	"bytes"
	"encoding/json"
	"net/http/httptest"
	"path/filepath"
	"testing"

	"github.com/cockroachdb/errors"
	"github.com/go-fuego/fuego"
	"github.com/nzoschke/deadca7/app/api"
	"github.com/nzoschke/deadca7/app/collection"
	"github.com/nzoschke/deadca7/app/db"
	"github.com/stretchr/testify/require"
	_ "modernc.org/sqlite"
)

// run executes the CLI in-process against base, returning stdout and exit code.
func run(t *testing.T, base string, args ...string) (string, int) {
	t.Helper()
	root := newRoot()
	out := &bytes.Buffer{}
	root.SetOut(out)
	root.SetErr(&bytes.Buffer{})
	root.SetArgs(append([]string{"--base-url", base}, args...))

	code := 0
	if err := root.Execute(); err != nil {
		code = exitAPI
		var ee *exitError
		if errors.As(err, &ee) {
			code = ee.code
		}
	}
	return out.String(), code
}

func id(t *testing.T, out string) string {
	t.Helper()
	var v struct {
		ID int64 `json:"id"`
	}
	require.NoError(t, json.Unmarshal([]byte(out), &v))
	require.NotZero(t, v.ID)
	return itoa(v.ID)
}

func itoa(v int64) string {
	b, _ := json.Marshal(v)
	return string(b)
}

func TestFlow(t *testing.T) {
	r := require.New(t)

	sdb, err := db.Open(filepath.Join(t.TempDir(), "test.db"))
	r.NoError(err)
	defer sdb.Close()

	s := fuego.NewServer(fuego.WithoutAutoGroupTags())
	api.Register(s, collection.New(sdb), nil)
	ts := httptest.NewServer(s.Mux)
	defer ts.Close()

	var collID, plID, cntID string

	steps := []struct {
		name   string
		args   []string
		code   int
		assert func(t *testing.T, out string)
	}{
		{
			name: "create collection",
			args: []string{"collections", "create", "--name", "Live 77", "--slug", "live-77"},
			assert: func(t *testing.T, out string) {
				require.Contains(t, out, `"slug": "live-77"`)
				collID = id(t, out)
			},
		},
		{
			name: "get collection",
			args: []string{"collections", "get", ""},
			assert: func(t *testing.T, out string) {
				require.Contains(t, out, `"name": "Live 77"`)
			},
		},
		{
			name: "list collections",
			args: []string{"collections", "list"},
			assert: func(t *testing.T, out string) {
				require.Contains(t, out, "live-77")
			},
		},
		{
			name: "create content",
			args: []string{"contents", "create", "--title", "Scarlet Begonias", "--artist", "GD", "--track-no", "1"},
			assert: func(t *testing.T, out string) {
				require.Contains(t, out, "Scarlet Begonias")
				cntID = id(t, out)
			},
		},
		{
			name: "create playlist",
			args: []string{"playlists", "create", "--collection", "", "--name", "Set 1"},
			assert: func(t *testing.T, out string) {
				require.Contains(t, out, `"name": "Set 1"`)
				plID = id(t, out)
			},
		},
		{
			name: "add content to playlist",
			args: []string{"playlists", "add", "", "", "--seq", "0"},
		},
		{
			name: "list playlist contents",
			args: []string{"playlists", "contents", ""},
			assert: func(t *testing.T, out string) {
				require.Contains(t, out, "Scarlet Begonias")
			},
		},
		{
			name: "missing required flag is a usage error",
			args: []string{"collections", "create", "--name", "no slug"},
			code: exitUsage,
		},
		{
			name: "not found is an api error",
			args: []string{"collections", "get", "999999"},
			code: exitAPI,
		},
		{
			name: "delete collection",
			args: []string{"collections", "delete", ""},
		},
	}

	for _, tt := range steps {
		t.Run(tt.name, func(t *testing.T) {
			args := patch(tt.args, collID, plID, cntID)
			out, code := run(t, ts.URL, args...)
			require.Equal(t, tt.code, code, "out=%s", out)
			if tt.assert != nil {
				tt.assert(t, out)
			}
		})
	}
}

// patch fills empty positional/flag slots with IDs captured from earlier steps,
// keeping the table readable without threading state through every row.
func patch(args []string, collID, plID, cntID string) []string {
	out := append([]string(nil), args...)
	switch {
	case len(out) >= 3 && out[0] == "collections" && (out[1] == "get" || out[1] == "delete") && out[2] == "":
		out[2] = collID
	case len(out) >= 4 && out[0] == "playlists" && out[1] == "create":
		out[3] = collID
	case len(out) >= 4 && out[0] == "playlists" && out[1] == "add":
		out[2], out[3] = plID, cntID
	case len(out) >= 3 && out[0] == "playlists" && out[1] == "contents":
		out[2] = plID
	}
	return out
}


ToolSearch

Question: select:WebFetch,WebSearch


Question: select:WebFetch,WebSearch


Now let me gather the external context — the existing vizlab port state and the Pro DJ Link protocol documentation that beat-link/crate-digger are built on.


WebFetch

Prompt: List every file in this directory and summarize what each Go file implements regarding Pioneer Pro DJ Link. What protocol features (device discovery, beat sync, status, metadata, NFS/rekordbox database) are implemented? Note anything marked unreliable, TODO, or incomplete.


The server returned HTTP 404 Not Found.

The response body was not retrieved. If this URL requires authentication, use an authenticated tool (e.g. `gh` for GitHub, or an MCP-provided fetch tool) instead of WebFetch.


Prompt: What are the main UDP ports and packet types in the Pioneer Pro DJ Link protocol (device announcement/discovery, beat packets, CDJ status, mixer status, metadata requests)? Summarize the protocol layers documented.


I'll check the vizlab repository using gh and search for the protocol documentation online.


Bash

cd /tmp && rm -rf vizlab-link && gh api repos/nzoschke/vizlab/contents/pkg/link 2>/dev/null | python3 -c "import sys,json; [print(f['name'], f['size'], f['type']) for f in json.load(sys.stdin)]" || echo "GH_API_FAILED"

List vizlab pkg/link files via gh api


WebSearch

Question: Pioneer Pro DJ Link protocol UDP ports 50000 50001 50002 beat announce status packet dysentery


anlz 0 dir
announce.go 3462 file
device.go 1229 file
discover.go 1642 file
link.go 2095 file
link_test.go 7225 file
media.go 3077 file
meta.go 2007 file
net.go 1327 file
nfs 0 dir
pdb.go 1219 file
pdb 0 dir
status.go 7438 file
Shell cwd was reset to /Users/noah/conductor/workspaces/deadca7/san-diego


Web search results for query: "Pioneer Pro DJ Link protocol UDP ports 50000 50001 50002 beat announce status packet dysentery"

Links: [{"title":"GitHub - kyleawayan/opus-quad-pro-dj-link-analysis: Pioneer DJ OPUS-QUAD Pro DJ Link Analysis · GitHub","url":"https://github.com/kyleawayan/opus-quad-pro-dj-link-analysis"},{"title":"Packet Types - DJ Link Ecosystem Analysis - Deep Symmetry","url":"https://djl-analysis.deepsymmetry.org/djl-analysis/packets.html"},{"title":"GitHub - Deep-Symmetry/dysentery: Exploring ways to participate in a Pioneer Pro DJ Link network · GitHub","url":"https://github.com/Deep-Symmetry/dysentery"},{"title":"GitHub - evanpurkhiser/prolink-connect: A Typescript / JavaScript library that is able to talk to Pioneer PROLINK enabled DJ equipment · GitHub","url":"https://github.com/evanpurkhiser/prolink-connect"},{"title":"What is the PRO DJ LINK function? – AlphaTheta Help Center","url":"https://support.pioneerdj.com/hc/en-us/articles/4405902925593-What-is-the-PRO-DJ-LINK-function"},{"title":"Pro DJ Link: Learn 5 “Secret” Features Of Pioneer DJ’s Protocol - MyHouseRadio FM - House Music Deep Soulful and Classics","url":"https://www.myhouseradio.fm/2018/10/22/pro-dj-link-learn-5-secret-features-of-pioneer-djs-protocol/"},{"title":"Pioneer Timecode Synchronization Software for PRO DJ LINK | ProDJLink","url":"https://www.prodjlink.com/"},{"title":"Pro DJ Link: How To Set Up Pioneer DJ Setups Properly - DJ TechTools","url":"https://djtechtools.com/2018/07/31/pro-dj-link-how-to-set-up-pioneer-dj-setups-properly/"},{"title":"Pioneer Pro DJ link: the ULTIMATE guide – DeeJay Plaza","url":"https://www.deejayplaza.com/en/articles/pro-dj-link"}]

Based on the search results, I found relevant information about the Pioneer Pro DJ Link protocol and the UDP ports you mentioned:

## Pioneer Pro DJ Link Protocol - UDP Ports

Packets sent to port 50000 seem primarily related to announcing the devices present on the network, and negotiating the channel (device) number assigned to each. Packets sent to port 50001 seem primarily related to beat synchronization, which is a core element of the protocol.

When you send your first announce packet on port 50000, the OPUS-QUAD will start sending UDP packets to you on port 50002.

## Packet Structure

DJ Link packets seem to all start with a fixed sequence of ten bytes, 51 73 70 74 31 57 6d 4a 4f 4c, which is followed by a byte that (combined with the port on which it was received) identifies what kind of information is found in the packet. For example, 06 is an announce packet, so a packet starting with 51 73 70 74 31 57 6d 4a 4f 4c 06 means it is an announce packet.

## Dysentery

The information was discovered by studying packet captures and with the help of dysentery, a bespoke protocol analysis tool written in Clojure. Dysentery is a research and reverse-engineering project that has been instrumental in documenting the Pro DJ Link protocol specifications.

REMINDER: You MUST include the sources above in your response to the user using markdown hyperlinks.

Question: Pioneer Pro DJ Link protocol UDP ports 50000 50001 50002 beat announce status packet dysentery


I need to examine the existing implementation in the vizlab package, particularly the link.go and link_test.go files to see what's currently working and what might be unreliable, along with the package documentation to understand the full scope of what's been implemented. Let me pull those key files to get a clearer picture.


The existing vizlab port is substantial (announce, device, discover, status, media, meta, pdb, nfs, anlz). Let me pull the test file and main link file to understand what's there and what's unreliable.


Bash

cd /tmp && for f in link.go link_test.go net.go discover.go; do echo "═══════════ $f ═══════════"; gh api repos/nzoschke/vizlab/contents/pkg/link/$f --jq '.content' 2>/dev/null | base64 -d; done 2>/dev/null | head -380

Fetch key vizlab link files


═══════════ link.go ═══════════
package link

import (
	"context"
	"net"
	"time"

	"github.com/nzoschke/codon/pkg/link/pdb"
	"github.com/pkg/errors"
)

type Callbacks struct {
	OnAir    func(Status) error
	OnDevice func(Device) error
	OnMeta   func(Status, Metadata, pdb.Track) error
	OnMount  func(Status, pdb.PDB) error
	OnStatus func(Status) error
	OnTrack  func(Status) error
}

type Link struct {
	Airs    map[DeviceID]bool     // latest onAir
	Devices map[DeviceID]Device   // latest devices
	Masters map[DeviceID]bool     // latest master
	Metas   map[DeviceID]Metadata // first track metadata
	Mnts    map[DeviceSlot]PDBMnt // latest PDB mounts
	Tracks  map[DeviceID]Status   // first track status

	cbs Callbacks

	c0 *net.UDPConn
	c2 *net.UDPConn
}

func New(cbs Callbacks) (*Link, func() error, error) {
	c0, err := net.ListenUDP("udp", &net.UDPAddr{
		IP:   net.IPv4zero,
		Port: 50000,
	})
	if err != nil {
		return nil, nil, errors.WithStack(err)
	}

	c2, err := net.ListenUDP("udp", &net.UDPAddr{
		IP:   net.IPv4zero,
		Port: 50002,
	})
	if err != nil {
		return nil, nil, errors.WithStack(err)
	}

	close := func() error {
		if err := c0.Close(); err != nil {
			return errors.WithStack(err)
		}

		if err := c2.Close(); err != nil {
			return errors.WithStack(err)
		}

		return nil
	}

	return &Link{
		Airs:    map[DeviceID]bool{},
		Devices: map[DeviceID]Device{},
		Masters: map[DeviceID]bool{},
		Metas:   map[DeviceID]Metadata{},
		Mnts:    map[DeviceSlot]PDBMnt{},
		Tracks:  map[DeviceID]Status{},

		cbs: cbs,

		c0: c0,
		c2: c2,
	}, close, nil
}

func (l *Link) Start(ctx context.Context) error {
	name := "vizlab"
	id := DeviceID(7)

	_, ipNet, addr, _, err := l.Announce(ctx, name, id, 5*time.Second)
	if err != nil {
		return errors.WithStack(err)
	}

	errch := make(chan error)

	go func() {
		errch <- l.KeepAlive(ctx, name, id, ipNet, addr)
	}()

	go func() {
		errch <- l.Discover(ctx)
	}()

	// FIXME: device discovery or retry mounts
	time.Sleep(5 * time.Second)
	go func() {
		errch <- l.Status(ctx)
	}()

	err = <-errch

	if err != nil {
		return errors.WithStack(err)
	}

	return nil
}
═══════════ link_test.go ═══════════
package link_test

import (
	"context"
	"errors"
	"slices"
	"testing"
	"time"

	"github.com/nzoschke/codon/pkg/link"
	"github.com/nzoschke/codon/pkg/link/nfs"
	"github.com/nzoschke/codon/pkg/link/pdb"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"golang.org/x/sync/errgroup"
)

// These tests require at least 1 CDJ with at least 1 media on the network

// TestInit verifies that one device is detected, a virtual CDJ is announced, and receives another player status,
// by sequentially receiving packets.
func TestInit(t *testing.T) {
	ctx := t.Context()
	a := assert.New(t)

	l, close, err := link.New(link.Callbacks{})
	a.NoError(err)
	defer close()

	vcdjID := link.DeviceID(8)
	_, _, _, s, err := l.Announce(ctx, "vizlink", vcdjID, 5*time.Second)
	a.NoError(err)

	a.Equal(s.PlayerName, "CDJ-3000")
	a.NotEqual(s.Device, vcdjID)
}

// TestDevices verifies that all devices are detected by contually processing keep-alive packets.
func TestDevices(t *testing.T) {
	ctx := t.Context()
	a := assert.New(t)

	ds := map[link.DeviceID]link.Device{}
	l, close, err := link.New(link.Callbacks{
		OnDevice: func(d link.Device) error {
			ds[d.ID] = d
			return nil
		},
	})
	a.NoError(err)
	defer close()

	vcdjID := link.DeviceID(8)
	_, _, _, _, err = l.Announce(ctx, "vizlink", vcdjID, 5*time.Second)
	a.NoError(err)

	ctx, cancel := context.WithTimeout(ctx, 3*time.Second)
	defer cancel()
	err = l.Discover(ctx)
	a.ErrorIs(err, context.DeadlineExceeded)

	a.Greater(len(ds), 3)
}

// TestStatuses verifies that all CDJ status is tracked by contually processing packets.
func TestStatuses(t *testing.T) {
	ctx := t.Context()
	a := assert.New(t)

	ss := []link.Status{}
	ds := map[link.DeviceID]link.Status{}
	l, close, err := link.New(link.Callbacks{
		OnStatus: func(s link.Status) error {
			ss = append(ss, s)
			ds[s.Device] = s
			return nil
		},
	})
	a.NoError(err)
	defer close()

	vcdjID := link.DeviceID(8)
	_, _, _, s, err := l.Announce(ctx, "vizlink", vcdjID, 5*time.Second)
	a.NoError(err)

	a.Equal(s.PlayerName, "CDJ-3000")

	ctx, cancel := context.WithTimeout(ctx, 3*time.Second)
	defer cancel()
	err = l.Status(ctx)
	a.ErrorIs(err, context.DeadlineExceeded)

	a.Greater(len(ds), 1)
	a.Greater(len(ss), 10)
}

// TestTracks verifies that all CDJ loaded tracks are tracked.
func TestTracks(t *testing.T) {
	ctx := t.Context()
	a := assert.New(t)
	r := require.New(t)

	ss := []link.Status{}
	ts := []link.Status{}
	l, close, err := link.New(link.Callbacks{
		OnStatus: func(s link.Status) error {
			ss = append(ss, s)
			return nil
		},
		OnTrack: func(t link.Status) error {
			ts = append(ts, t)
			return nil
		},
	})
	a.NoError(err)
	defer close()

	vcdjID := link.DeviceID(8)
	_, _, _, s, err := l.Announce(ctx, "vizlink", vcdjID, 5*time.Second)
	a.NoError(err)

	a.Equal(s.PlayerName, "CDJ-3000")

	ctx, cancel := context.WithTimeout(ctx, 3*time.Second)
	defer cancel()
	err = l.Status(ctx)
	a.ErrorIs(err, context.DeadlineExceeded)

	a.Greater(len(ss), 10)
	r.Greater(len(ts), 0)
	a.NotEmpty(ts[0].TrackID)
}

// TestTrackMetas verifies that all CDJ loaded tracks have metadata fetched from PDB and NFS.
func TestTrackMetas(t *testing.T) {
	ctx := t.Context()
	a := assert.New(t)

	ms := []link.Metadata{}
	ts := []pdb.Track{}
	l, close, err := link.New(link.Callbacks{
		OnMeta: func(s link.Status, m link.Metadata, t pdb.Track) error {
			ms = append(ms, m)
			ts = append(ts, t)
			return nil
		},
	})
	a.NoError(err)
	defer close()

	dctx, dcancel := context.WithTimeout(ctx, 5*time.Second)
	defer dcancel()
	err = l.Discover(dctx)
	a.ErrorIs(err, context.DeadlineExceeded)

	vcdjID := link.DeviceID(8)
	_, _, _, s, err := l.Announce(ctx, "vizlink", vcdjID, 5*time.Second)
	a.NoError(err)

	a.Equal(s.PlayerName, "CDJ-3000")

	ctx, cancel := context.WithTimeout(ctx, 3*time.Second)
	defer cancel()
	err = l.Status(ctx)
	a.ErrorIs(err, context.DeadlineExceeded)

	a.Greater(len(ms), 1)
	a.NotEmpty(ms[0].Title)
	a.Equal(ms[0].Title, ts[0].Title)
}

// TestMediaQuery verifies the virtual CDJ queries and receives another player media response,
// by sequentially receiving packets.
// It does work but is unreliable.
func TestMediaQuery(t *testing.T) {
	ctx := t.Context()
	a := assert.New(t)

	l, close, err := link.New(link.Callbacks{})
	a.NoError(err)
	defer close()

	vcdjID := link.DeviceID(8)
	deviceIP, ipNet, addr, s, err := l.Announce(ctx, "vizlink", vcdjID, 5*time.Second)
	a.NoError(err)

	go l.KeepAlive(ctx, "vizlink", vcdjID, ipNet, addr)

	ds := link.DeviceSlot{s.Device, 0}
	if s.SDState == link.MediaStateLoaded {
		ds.Slot = link.SlotSD
	}
	if s.USBState == link.MediaStateLoaded {
		ds.Slot = link.SlotUSB
	}

	if ds.Slot == 0 {
		a.Fail("no media loaded on %s %s", s.PlayerName, s.Device)
	}

	m, err := l.Media(ctx, "vizlink", vcdjID, ipNet.IP, deviceIP, ds, 2*time.Second)
	a.NoError(err)
	a.NotEmpty(m.Name)
}

// TestPDBs reads and parses all PDBs from all slots
func TestPDBs(t *testing.T) {
	ctx := t.Context()
	a := assert.New(t)

	cdjs := []link.Device{}
	l, close, err := link.New(link.Callbacks{
		OnDevice: func(d link.Device) error {
			if d.Type == link.DeviceTypeCDJ {
				cdjs = append(cdjs, d)
			}

			return nil
		},
	})
	a.NoError(err)
	defer close()

	ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()
	err = l.Discover(ctx)
	a.ErrorIs(err, context.DeadlineExceeded)

	a.Greater(len(cdjs), 1)

	pdbs := []*pdb.PDB{}
	for _, d := range cdjs {
		for _, s := range link.Slots {
			pm, err := link.PDB(d.IP, link.DeviceSlot{
				Device: d.ID,
				Slot:   s,
			})
			if err != nil {
				if errors.Is(err, nfs.ERRNoMount) {
					continue
				}
				t.Fatalf("%v\n", err)
			}

			pdbs = append(pdbs, pm.PDB)
		}
	}

	a.Greater(len(pdbs), 1)
}

// TestMetas reads and parses metadata like Picture tag for all Tracks from all PDBs from all slots.
// It is a stress test for the NFS client.
func TestMetas(t *testing.T) {
	numTracks := 0 // 0 to read all tracks

	ctx := t.Context()
	a := assert.New(t)

	cdjs := []link.Device{}
	l, close, err := link.New(link.Callbacks{
		OnDevice: func(d link.Device) error {
			if d.Type == link.DeviceTypeCDJ {
				cdjs = append(cdjs, d)
			}

			return nil
Shell cwd was reset to /Users/noah/conductor/workspaces/deadca7/san-diego


 I'm seeing the core issue now — the current `link/` endpoint in San Diego is just a basic catalog share mechanism, but the user wants to reserve "link" for Pro DJ Link integration. I need to move that trivial share functionality elsewhere and free up the namespace.

For Part A, I'll relocate the share-link code into the `app` package directly — either as a small helper function in `app.go` or a dedicated `share.go` file — then remove the separate `link/` module entirely from the workspace and dependencies.

For Part B, the real work is a test-first approach to porting the Pro DJ Link protocol: start by documenting the protocol (discovery on port 50000, beat sync on 50001, status on 50002, plus NFS/RPC for rekordbox database access), then capture live traffic from the CDJ-3000 as fixture files, build a test harness that replays those fixtures against the parsers, and finally port the vizlab code module-by-module while fixing the reliability issues — replacing the sleep hacks and unreliable media queries with solid fixture-driven tests. The tricky part is that some protocol interactions are passive broadcasts while others require active participation, so the capture tooling itself needs to announce as a virtual CDJ to provoke responses.

For the repo structure, I'll put the protocol documentation in `link/doc/protocol.md`, store captured pcap fixtures in `link/testdata/`, and add a capture CLI tool in `link/cmd/` to help record live traffic from the network.

Now I need to check whether `app.Item.Share()` is actually used anywhere in the codebase. The user mentioned moving anything in `link/` that's unused into the `app` module, so I should verify if Share is called in tests or the API before deciding whether to fold it in.


I have a thorough picture now. Let me do two quick checks to nail down Part A (the relocation) precisely.


No matches found


 The `app.Item` and `Share()` function are unused scaffolding, and `link.New` is only called from `app/app.go` which is itself placeholder code. So Part A is straightforward — the entire `app/app.go` and `link/` directory are just boilerplate. The user wants to repurpose `link/` for the Pro DJ Link port, but technically it's already being used by app.go even though that's also unused.

The cleanest approach is to fold the share-link function directly into the `app` package, remove the separate `link` module entirely, and free up `link/` for the protocol port. Now I'll structure a comprehensive plan covering the findings, the relocation step, and the phased approach to porting the protocol — including the key facts about ports, magic headers, and the split between beat-link (live protocol) and crate-digger (PDB/NFS) — then ask for confirmation before making any changes.


I have everything I need to write the plan. Here's the situation and a concrete plan.

## What's actually in `link/` today

The current `link/` package has nothing to do with Pro DJ Link. It's placeholder scaffolding:

```go
// link/link.go
func New(id string) string { return "deadca7://item/" + id }
```

Its only consumer is `app/app.go`'s `Item.Share()` — and `Item`/`Share` aren't referenced anywhere else in the tree (no tests, no API, no CLI). So both are dead scaffolding. The name `link` is the thing you want back for the Pro DJ Link port; the share-link helper just needs to fold into `app`.

## What the real `link` will be

A Go port of two Deep-Symmetry projects, which split cleanly:

- **beat-link** → the *live network protocol* (UDP). Three ports, each a distinct concern:
  - `50000` — device announce / discovery / keep-alive (channel-number negotiation)
  - `50001` — beat sync (broadcast beat packets)
  - `50002` — CDJ/mixer status (and where a CDJ starts sending status *to you* once you announce)
  - All packets share a 10-byte magic header `51 73 70 74 31 57 6d 4a 4f 4c` + a type byte.
- **crate-digger** → the *rekordbox database* side: mount the CDJ's media over NFS (RPC portmap → mount → NFS read), pull `export.pdb`, parse PDB tables + ANLZ (`.DAT`/`.EXT`) analysis files for metadata/waveform/beatgrid.

## State of the existing vizlab port

`vizlab/pkg/link` is already substantial — `announce.go device.go discover.go link.go media.go meta.go net.go pdb.go status.go` plus `anlz/ nfs/ pdb/` subpackages, with a real test suite. But it's explicitly unreliable in the spots that matter:

- `link.go` `Start()` has `// FIXME: device discovery or retry mounts` papered over with a `time.Sleep(5 * time.Second)`.
- `TestMediaQuery`: *"It does work but is unreliable."*
- Tests require live hardware ("at least 1 CDJ with at least 1 media on the network") — so there's no way to reproduce a failure deterministically. That's the root cause of "not reliable": no fixtures, timing-dependent, hardware-gated.

It also imports `github.com/pkg/errors` (CLAUDE.md mandates `cockroachdb/errors`) and lives under module `github.com/nzoschke/codon/...`.

---

## Proposed plan

### Part 0 — Relocate the misplaced share-link (small, mechanical)
1. Move the `deadca7://item/...` helper into the `app` package (e.g. fold `New` into `app/app.go` as an unexported `shareLink(id)` used by `Item.Share`).
2. Delete `link/` (all three files).
3. Remove `./link` from `go.work`, and drop the `require` + `replace` for `github.com/nzoschke/deadca7/link` in `app/go.mod`.
4. `go build ./... && go test ./...` to confirm green.

This frees the `link/` path. (Open question below on whether `link` should be its own module again or live under `app/`.)

### Part 1 — Document the protocol first (the "how")
Write `link/doc/protocol.md` distilling the Deep-Symmetry analysis into exactly what we need to implement and assert against — per-port packet layouts, the announce/keep-alive handshake, status fields we care about (player #, BPM, beat, pitch, on-air, loaded track id + slot), and the crate-digger flow (portmap→mount→NFS→PDB→ANLZ). This doc doubles as the spec the tests encode. Ground it in `djl-analysis.deepsymmetry.org` and cross-check against the existing vizlab parsers.

### Part 2 — Capture from the CDJ-3000 (the ground truth)
Build deterministic fixtures so tests no longer need hardware:
- **Passive broadcasts** (announce, keep-alive, beat, status) → capture with `tcpdump -i <iface> -w testdata/<scenario>.pcap 'udp port 50000 or 50001 or 50002'`.
- **Active flows** (metadata query, NFS mount, PDB read) only happen once we present a *virtual CDJ* — a CDJ won't send status/metadata to a device that hasn't announced. So we need a tiny capture tool (`link/cmd/capture`) that announces + keep-alives as a virtual CDJ while dumping every received datagram (src/dst/port/ts/payload) to a fixture, run alongside tcpdump for the RPC/NFS dynamic-port traffic.
- Capture a labeled scenario set: idle, track loaded, playing-with-beats, two-deck, media-mount+PDB-read. Trim and check in small fixtures under `link/testdata/`.
- Note: this needs the Mac and CDJ-3000 on one flat subnet (DJ Link is link-local `169.254.x` absent DHCP) — worth confirming the network setup before capturing.

### Part 3 — Fixture-replay test harness (the reliable tests)
- Golden/table-driven decode tests that feed captured packets into the parsers and assert decoded fields — fast, hermetic, no hardware. Structured like `flow_test.go` (a table of named steps with `assert` closures).
- Keep a *separate* live integration suite (the vizlab-style "needs a CDJ" tests) but gate it behind `testing.Short()` / an env var, mirroring the repo's convention of gating browser integration tests as "non-short."

### Part 4 — Port the modules, driven by the fixtures
Bring vizlab modules over one at a time — `net → announce/discover → status → beat → pdb → nfs → meta/media` — each landing with its replay fixtures and tests before moving on. While porting: rename to `github.com/nzoschke/deadca7/link`, swap `pkg/errors`→`cockroachdb/errors`, and specifically kill the unreliable bits — replace the `time.Sleep(5s)` FIXME with proper readiness signalling (wait for discovery/mount events), and make the media query deterministic against its fixture.

---

## Open questions before I start
1. **Module shape:** should `link` be its own go.work module again (like vizlab), or live as `app/link` inside the app module? Given NFS/RPC deps it may be cleaner as its own module.
2. **Part 0 now, or bundle it?** I can do the mechanical relocation immediately, or hold it until you've confirmed the module shape.
3. **Capture access:** is the CDJ-3000 reachable on your network right now, and do you know which Mac interface it's on? That gates Part 2.

Want me to start with Part 0 (relocate + clean build) while we settle the module-shape question, or would you rather I draft the Part 1 protocol doc first?

Sources: [DJL Analysis — Packet Types](https://djl-analysis.deepsymmetry.org/djl-analysis/packets.html) · [dysentery](https://github.com/Deep-Symmetry/dysentery) · [beat-link](https://github.com/Deep-Symmetry/beat-link) · [crate-digger](https://github.com/Deep-Symmetry/crate-digger)


1. link is its own module in the workspace
2. we moved link in another pending PR
3. it should be, its on and a reference SD card is loaded. can you verify


 The user clarified that the link module is separate, the relocation work is already in progress elsewhere, and the CDJ-3000 is powered on with a reference SD card loaded. Now I need to verify the device is reachable on the network by detecting network interfaces and checking for DJ Link traffic.

DJ Link devices broadcast keep-alive announcements on UDP port 50000, and they typically connect via link-local addresses (169.254.x.x) or DHCP subnets. I'll start by examining the network interfaces to identify which one might be connected to the DJ network, then listen for those UDP broadcasts to confirm the CDJ-3000 is present.


Skipping Part 0 (handled in your other PR) — `link` stays its own workspace module. Let me verify the CDJ-3000 is actually reachable on the network. First, what interfaces/subnets does this Mac have?


ifconfig | grep -A4 '^[a-z]' | grep -E '^[a-z]|inet ' | grep -v 'inet6'

List interfaces and IPv4 addresses


lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
	inet 127.0.0.1 netmask 0xff000000
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
stf0: flags=0<> mtu 1280
anpi0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
anpi2: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
anpi1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
en4: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
en5: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
en7: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
en1: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
en2: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
en3: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
bridge0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500
ap1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	inet 192.168.0.160 netmask 0xffffff00 broadcast 192.168.0.255
awdl0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
llw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
utun1: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380
utun2: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 2000
utun3: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1000
utun4: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380
utun5: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380
utun6: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380
utun7: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380
utun8: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380
utun9: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380


1. link is its own module in the workspace 2. we moved link in another pending PR  3. it should be, its on and a reference SD card is loaded. can you verify


 The DJ network is on 192.168.0.x via DHCP, so the CDJ-3000 should be reachable on that same subnet. I'm thinking about listening for DJ Link keep-alive broadcasts on UDP port 50000—either with a small Go program or a simple netcat command to capture the broadcast traffic.

Since the vizlab link already binds to port 50000, I'll write a quick Go listener that can run for a few seconds and capture incoming packets. I'm planning to parse the announce/keep-alive packet structure—the magic header is 10 bytes, followed by a type byte (0x06 for keep-alive), and the device name starts at offset 0x0c for 20 bytes. This should let me identify the CDJ by its source IP and extract its name from the packets.

Writing the listener...


Only `en0` is up: `192.168.0.160/24`. So the DJ network is a regular `192.168.0.x` DHCP subnet (not link-local). DJ Link devices broadcast keep-alive packets on UDP 50000 every ~1.5s — let me listen for them to confirm the CDJ-3000 is present and announce itself.


cat > /tmp/djlisten.go <<'EOF'
package main

import (
	"bytes"
	"fmt"
	"net"
	"time"
)

var magic = []byte{0x51, 0x73, 0x70, 0x74, 0x31, 0x57, 0x6d, 0x4a, 0x4f, 0x4c}

func main() {
	c, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.IPv4zero, Port: 50000})
	if err != nil {
		fmt.Println("listen 50000:", err)
		return
	}
	defer c.Close()
	c.SetReadDeadline(time.Now().Add(8 * time.Second))
	seen := map[string]string{}
	buf := make([]byte, 1500)
	for {
		n, addr, err := c.ReadFromUDP(buf)
		if err != nil {
			break
		}
		if n < 0x2c || !bytes.Equal(buf[:10], magic) {
			seen[addr.IP.String()] = fmt.Sprintf("non-DJLink len=%d", n)
			continue
		}
		typ := buf[10]
		name := string(bytes.TrimRight(buf[0x0c:0x0c+20], "\x00"))
		seen[addr.IP.String()] = fmt.Sprintf("type=0x%02x name=%q len=%d", typ, name, n)
	}
	if len(seen) == 0 {
		fmt.Println("NO PACKETS on UDP 50000 in 8s")
		return
	}
	for ip, s := range seen {
		fmt.Printf("%-16s %s\n", ip, s)
	}
}
EOF
cd /tmp && go run djlisten.go

Listen for DJ Link keep-alive broadcasts on UDP 50000


192.168.0.192    type=0x06 name="CDJ-3000" len=54
Shell cwd was reset to /Users/noah/conductor/workspaces/deadca7/san-diego


✅ **Verified — the CDJ-3000 is on the network and broadcasting.**

- **Device:** `CDJ-3000` at **`192.168.0.192`**
- **This Mac:** `192.168.0.160` (interface **`en0`**), same `/24` subnet — they can talk directly.
- **Packet:** type `0x06` keep-alive, 54 bytes, with the correct DJ Link magic header (`51 73 70 74 31 57 6d 4a 4f 4c`). So discovery-layer traffic is flowing and decodable right now.

What I couldn't confirm without actively participating: the **status/metadata/NFS** flows. A CDJ only sends status (port 50002) and answers metadata/NFS requests *after* a virtual CDJ has announced itself — so those need the capture tool from Part 2, not passive listening. The reference SD card being loaded is exactly what we need to exercise the crate-digger (PDB/NFS) side once we get there.

One concrete implication for the plan: since the network is a real `192.168.0.x` DHCP subnet (not link-local `169.254.x`), the capture tool should announce with a DHCP-assigned address rather than self-assigning — matches how your CDJ is configured.

Recommended next step: **Part 1 (write `link/doc/protocol.md`)** in parallel with building the **Part 2 capture tool**, then do a first real capture against `192.168.0.192` — starting with passive announce/keep-alive (already confirmed working), then an active status capture once the virtual-CDJ announce is in place.

Want me to scaffold the `link` module (`go.mod`, `cmd/capture`, `testdata/`, `doc/protocol.md`) and write the protocol doc now?


yes start, we don't need the protocol doc, we just need a TODO.md with parts of the protocol to capture and test


 The user wants me to scaffold the link module with a TODO.md file listing protocol parts to capture and test, plus the basic structure (go.mod, cmd/capture, testdata/). I'm a bit cautious about the existing link module since it's being moved in another PR, but the user confirmed to proceed and that link should be its own module in the workspace, so I'll go ahead with the scaffolding.

I'm realizing there's a potential conflict: the other PR moves the share-link code out of link/ into app, and my branch would be replacing link/ with the Pro DJ Link port. Both PRs would be modifying or removing the same files, which could cause merge conflicts. But since the user is aware of parallel PRs and explicitly said to start, I'll proceed with replacing the link module contents.

My plan is to create a working capture tool that listens on the DJ Link UDP ports (50000, 50002) and records packets to a JSONL fixture file for testing, then build out the packet parsing and test suite incrementally. However, there's a dependency issue: the app module currently imports link.New from the share-link code, so if I delete that, the app won't build on my branch. I need to either keep link.New temporarily or coordinate with the other PR's changes to app.

The safest approach is to add the Pro DJ Link code as new files (packet.go, cmd/capture, testdata) while leaving the existing link.go and link_test.go untouched for now. That way both PRs can coexist without breaking the build, and when they merge, the share-link code gets removed by the other PR while my protocol code remains. I'll avoid defining a conflicting New function in the link package until the share-link version is gone.

For the capture tool, I need to decide whether to add cockroachdb/errors as a dependency per the coding standards, or keep it stdlib-only to minimize friction during scaffolding.


Starting now. Plan for this pass: scaffold the `link` module with a working **capture tool**, take a real fixture from the CDJ-3000, add a **fixture-replay decoder + test** to prove the loop works end-to-end, and write **`link/TODO.md`** as the capture/test checklist. I'll add these as new files alongside the existing `link.go` (which your other PR is relocating) so nothing breaks on this branch.

Let me check the errors dep version the app uses, so the new module matches.


grep cockroachdb/errors /Users/noah/conductor/workspaces/deadca7/san-diego/app/go.mod; echo "---"; grep -E 'cockroachdb/errors' /Users/noah/conductor/workspaces/deadca7/san-diego/go.work.sum | head -3

Find cockroachdb/errors version


	github.com/cockroachdb/errors v1.13.0
---


I need to add the cockroachdb/errors dependency to the link module's go.mod and go.sum files since it's already in the app module's cache, so running go mod tidy should pull it in offline. Let me start writing out those files.


Now let me build the capture tool, decoder, test, and TODO. Writing them all:


Write

// Command capture records raw Pro DJ Link UDP datagrams to a JSONL fixture.
//
// It passively listens on the DJ Link discovery, beat, and status ports and
// writes one Packet per line so tests can replay real CDJ traffic without
// hardware. Active flows (status, metadata, NFS) that require announcing a
// virtual CDJ are not yet captured; see link/TODO.md.
package main

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"net"
	"os"
	"os/signal"
	"time"

	"github.com/cockroachdb/errors"
	"golang.org/x/sync/errgroup"
)

// Packet is one recorded UDP datagram.
type Packet struct {
	Data string `json:"data"`
	Len  int    `json:"len"`
	Port int    `json:"port"`
	Src  string `json:"src"`
	TS   int64  `json:"ts"`
}

func main() {
	out := flag.String("out", "capture.jsonl", "output JSONL fixture path")
	secs := flag.Int("secs", 8, "capture duration in seconds")
	flag.Parse()

	if err := run(*out, time.Duration(*secs)*time.Second); err != nil {
		fmt.Fprintf(os.Stderr, "%+v\n", err)
		os.Exit(1)
	}
}

func run(out string, d time.Duration) error {
	ports := []int{50000, 50001, 50002}

	f, err := os.Create(out)
	if err != nil {
		return errors.WithStack(err)
	}
	defer f.Close()

	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
	defer cancel()
	ctx, cancel = context.WithTimeout(ctx, d)
	defer cancel()

	enc := json.NewEncoder(f)
	pkts := make(chan Packet)

	g, ctx := errgroup.WithContext(ctx)
	for _, port := range ports {
		g.Go(func() error { return listen(ctx, port, pkts) })
	}

	g.Go(func() error {
		n := 0
		for {
			select {
			case <-ctx.Done():
				fmt.Fprintf(os.Stderr, "captured %d packets to %s\n", n, out)
				return nil
			case p := <-pkts:
				if err := enc.Encode(p); err != nil {
					return errors.WithStack(err)
				}
				n++
			}
		}
	})

	if err := g.Wait(); err != nil && !errors.Is(err, context.DeadlineExceeded) {
		return err
	}
	return nil
}

func listen(ctx context.Context, port int, pkts chan<- Packet) error {
	c, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.IPv4zero, Port: port})
	if err != nil {
		return errors.WithStack(err)
	}
	defer c.Close()

	go func() {
		<-ctx.Done()
		c.Close()
	}()

	buf := make([]byte, 1500)
	for {
		n, addr, err := c.ReadFromUDP(buf)
		if err != nil {
			if ctx.Err() != nil {
				return nil
			}
			return errors.WithStack(err)
		}
		select {
		case pkts <- Packet{
			Data: fmt.Sprintf("%x", buf[:n]),
			Len:  n,
			Port: port,
			Src:  addr.String(),
			TS:   time.Now().UnixMilli(),
		}:
		case <-ctx.Done():
			return nil
		}
	}
}


File created successfully at: /Users/noah/conductor/workspaces/deadca7/san-diego/link/cmd/capture/main.go (file state is current in your context — no need to Read it back)

// Command capture records raw Pro DJ Link UDP datagrams to a JSONL fixture.
//
// It passively listens on the DJ Link discovery, beat, and status ports and
// writes one Packet per line so tests can replay real CDJ traffic without
// hardware. Active flows (status, metadata, NFS) that require announcing a
// virtual CDJ are not yet captured; see link/TODO.md.
package main

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"net"
	"os"
	"os/signal"
	"time"

	"github.com/cockroachdb/errors"
	"golang.org/x/sync/errgroup"
)

// Packet is one recorded UDP datagram.
type Packet struct {
	Data string `json:"data"`
	Len  int    `json:"len"`
	Port int    `json:"port"`
	Src  string `json:"src"`
	TS   int64  `json:"ts"`
}

func main() {
	out := flag.String("out", "capture.jsonl", "output JSONL fixture path")
	secs := flag.Int("secs", 8, "capture duration in seconds")
	flag.Parse()

	if err := run(*out, time.Duration(*secs)*time.Second); err != nil {
		fmt.Fprintf(os.Stderr, "%+v\n", err)
		os.Exit(1)
	}
}

func run(out string, d time.Duration) error {
	ports := []int{50000, 50001, 50002}

	f, err := os.Create(out)
	if err != nil {
		return errors.WithStack(err)
	}
	defer f.Close()

	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
	defer cancel()
	ctx, cancel = context.WithTimeout(ctx, d)
	defer cancel()

	enc := json.NewEncoder(f)
	pkts := make(chan Packet)

	g, ctx := errgroup.WithContext(ctx)
	for _, port := range ports {
		g.Go(func() error { return listen(ctx, port, pkts) })
	}

	g.Go(func() error {
		n := 0
		for {
			select {
			case <-ctx.Done():
				fmt.Fprintf(os.Stderr, "captured %d packets to %s\n", n, out)
				return nil
			case p := <-pkts:
				if err := enc.Encode(p); err != nil {
					return errors.WithStack(err)
				}
				n++
			}
		}
	})

	if err := g.Wait(); err != nil && !errors.Is(err, context.DeadlineExceeded) {
		return err
	}
	return nil
}

func listen(ctx context.Context, port int, pkts chan<- Packet) error {
	c, err := net.ListenUDP("udp", &net.UDPAddr{IP: net.IPv4zero, Port: port})
	if err != nil {
		return errors.WithStack(err)
	}
	defer c.Close()

	go func() {
		<-ctx.Done()
		c.Close()
	}()

	buf := make([]byte, 1500)
	for {
		n, addr, err := c.ReadFromUDP(buf)
		if err != nil {
			if ctx.Err() != nil {
				return nil
			}
			return errors.WithStack(err)
		}
		select {
		case pkts <- Packet{
			Data: fmt.Sprintf("%x", buf[:n]),
			Len:  n,
			Port: port,
			Src:  addr.String(),
			TS:   time.Now().UnixMilli(),
		}:
		case <-ctx.Done():
			return nil
		}
	}
}


I need to update the go.mod file to include the cockroachdb/errors and golang.org/x/sync dependencies, then run go mod tidy to resolve them. Since the capture tool runs as a real command outside the workflow sandbox, I don't need to worry about Date.now restrictions that apply to Workflow scripts.


module github.com/nzoschke/deadca7/link

go 1.26.4

require (
	github.com/cockroachdb/errors v1.13.0
	golang.org/x/sync v0.10.0
)


The file /Users/noah/conductor/workspaces/deadca7/san-diego/link/go.mod has been updated successfully. (file state is current in your context — no need to Read it back)

module github.com/nzoschke/deadca7/link

go 1.26.4

require (
	github.com/cockroachdb/errors v1.13.0
	golang.org/x/sync v0.10.0
)

+  github.com/cockroachdb/errors v1.13.0


initialization failed: packages.Load error: err: exit status 1: stderr: go: go.work requires go >= 1.26.4 (running go 1.26.0)


There's a version mismatch between what the diagnostics are reporting and what go.work actually requires—I'm running 1.26.0 but the workspace needs at least 1.26.4. Let me verify the actual Go version installed.


Bash

go version; echo "---"; which go; echo "GOFLAGS=$GOFLAGS GOTOOLCHAIN=$GOTOOLCHAIN"

Check go version and toolchain


go version go1.26.4 darwin/arm64
---
/opt/homebrew/bin/go
GOFLAGS= GOTOOLCHAIN=


The shell has Go 1.26.4 while the LSP diagnostics are using 1.26.0, but that's fine since the build and tests will use the shell version. I'm going to run go mod tidy to clean up dependencies, capture a fixture, then build.


Shell `go` is 1.26.4 (the LSP just uses an older toolchain — harmless). Let me tidy the module deps.


cd /Users/noah/conductor/workspaces/deadca7/san-diego/link && go mod tidy 2>&1 | tail -20 && echo "---BUILD---" && go build ./... 2>&1 | tail -20 && echo "OK"

Tidy and build the link module


go: downloading github.com/cockroachdb/errors v1.13.0
go: downloading github.com/getsentry/sentry-go v0.46.0
go: downloading github.com/stretchr/testify v1.8.4
go: downloading golang.org/x/text v0.23.0
---BUILD---
go: downloading golang.org/x/sync v0.20.0
go: downloading golang.org/x/sys v0.45.0
go: downloading golang.org/x/text v0.37.0
OK


1	module github.com/nzoschke/deadca7/link
2
3	go 1.26.4
4
5	require (
6		github.com/cockroachdb/errors v1.13.0
7		golang.org/x/sync v0.12.0
8	)
9
10	require (
11		github.com/cockroachdb/logtags v0.0.0-20230118201751-21c54148d20b // indirect
12		github.com/cockroachdb/redact v1.1.5 // indirect
13		github.com/getsentry/sentry-go v0.46.0 // indirect
14		github.com/gogo/protobuf v1.3.2 // indirect
15		github.com/kr/pretty v0.3.1 // indirect
16		github.com/kr/text v0.2.0 // indirect
17		github.com/pkg/errors v0.9.1 // indirect
18		github.com/rogpeppe/go-internal v1.9.0 // indirect
19		golang.org/x/sys v0.31.0 // indirect
20		golang.org/x/text v0.23.0 // indirect
21	)


Builds clean. Now let me capture a real fixture from the CDJ-3000.


mkdir -p testdata && go run ./cmd/capture -out testdata/keepalive.jsonl -secs 6 2>&1; echo "---FIXTURE---"; wc -l testdata/keepalive.jsonl; head -2 testdata/keepalive.jsonl

Capture keep-alive fixture from CDJ-3000


captured 7 packets to testdata/keepalive.jsonl
---FIXTURE---
       7 testdata/keepalive.jsonl
{"data":"5173707431576d4a4f4c404e58532d4757000000000000000000000000000001011900020201","len":38,"port":50002,"src":"192.168.0.192:44182","ts":1780847621951}
{"data":"5173707431576d4a4f4c060043444a2d33303030000000000000000000000000010300360301c83dfc1126c2c0a800c0010000000164","len":54,"port":50000,"src":"192.168.0.192:45873","ts":1780847622255}


 Looking at the packet structure from the captured data, I'm parsing the header: the magic bytes are followed by a type field at offset 0x0a showing 0x40, and then what appears to be a device identifier "NXS-GW" in the subsequent bytes.

Now I'm examining the keep-alive packet on port 50000 with type 0x06, which contains the device name at offset 0x0c (20 bytes), followed by protocol version, length, device number, device type, MAC address, and IP address fields. Decoding the captured hex shows "CDJ-3000" as the device name, device number 3, IP 192.168.0.192, and MAC c8:3d:fc:11:26:c2.

I'm going to write a packet decoder in Go with a KeepAlive struct and validation logic that checks the magic header and packet type, returning typed errors for unsupported packets, then create a table-driven test using the captured fixture data.


Real fixtures captured — including a keep-alive (type `0x06`, "CDJ-3000") on 50000 and a type `0x40` packet on 50002. Now the decoder + replay test to close the loop, then `TODO.md`.


Write

package link

import (
	"bytes"
	"net"

	"github.com/cockroachdb/errors"
)

// Magic is the ten-byte preamble that begins every Pro DJ Link packet.
var Magic = []byte{0x51, 0x73, 0x70, 0x74, 0x31, 0x57, 0x6d, 0x4a, 0x4f, 0x4c}

// Type is the packet kind, found at the byte following Magic and interpreted
// together with the UDP port the packet arrived on.
type Type byte

const (
	TypeKeepAlive Type = 0x06
)

// ErrNotDJLink is returned when a payload does not begin with Magic.
var ErrNotDJLink = errors.New("not a DJ Link packet")

// KeepAlive is a device announcement broadcast on port 50000.
type KeepAlive struct {
	Device byte
	IP     net.IP
	MAC    net.HardwareAddr
	Name   string
}

// DecodeKeepAlive parses a keep-alive (type 0x06) packet.
func DecodeKeepAlive(b []byte) (KeepAlive, error) {
	if len(b) < 0x30 || !bytes.Equal(b[:len(Magic)], Magic) {
		return KeepAlive{}, ErrNotDJLink
	}
	if t := Type(b[0x0a]); t != TypeKeepAlive {
		return KeepAlive{}, errors.Errorf("want keep-alive 0x06, got 0x%02x", byte(t))
	}

	return KeepAlive{
		Device: b[0x24],
		IP:     net.IP(append([]byte(nil), b[0x2c:0x30]...)),
		MAC:    net.HardwareAddr(append([]byte(nil), b[0x26:0x2c]...)),
		Name:   string(bytes.TrimRight(b[0x0c:0x20], "\x00")),
	}, nil
}


File created successfully at: /Users/noah/conductor/workspaces/deadca7/san-diego/link/packet.go (file state is current in your context — no need to Read it back)

package link

import (
	"bytes"
	"net"

	"github.com/cockroachdb/errors"
)

// Magic is the ten-byte preamble that begins every Pro DJ Link packet.
var Magic = []byte{0x51, 0x73, 0x70, 0x74, 0x31, 0x57, 0x6d, 0x4a, 0x4f, 0x4c}

// Type is the packet kind, found at the byte following Magic and interpreted
// together with the UDP port the packet arrived on.
type Type byte

const (
	TypeKeepAlive Type = 0x06
)

// ErrNotDJLink is returned when a payload does not begin with Magic.
var ErrNotDJLink = errors.New("not a DJ Link packet")

// KeepAlive is a device announcement broadcast on port 50000.
type KeepAlive struct {
	Device byte
	IP     net.IP
	MAC    net.HardwareAddr
	Name   string
}

// DecodeKeepAlive parses a keep-alive (type 0x06) packet.
func DecodeKeepAlive(b []byte) (KeepAlive, error) {
	if len(b) < 0x30 || !bytes.Equal(b[:len(Magic)], Magic) {
		return KeepAlive{}, ErrNotDJLink
	}
	if t := Type(b[0x0a]); t != TypeKeepAlive {
		return KeepAlive{}, errors.Errorf("want keep-alive 0x06, got 0x%02x", byte(t))
	}

	return KeepAlive{
		Device: b[0x24],
		IP:     net.IP(append([]byte(nil), b[0x2c:0x30]...)),
		MAC:    net.HardwareAddr(append([]byte(nil), b[0x26:0x2c]...)),
		Name:   string(bytes.TrimRight(b[0x0c:0x20], "\x00")),
	}, nil
}


Now I'm writing the test file that loads the JSONL fixture, parses each packet from hex, filters for port 50000 with type 0x06, decodes them, and asserts that a CDJ-3000 is found using a table-driven approach with testify assertions and requirements.


package link

import (
	"bufio"
	"encoding/hex"
	"encoding/json"
	"os"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// packet mirrors a record written by cmd/capture.
type packet struct {
	Data string `json:"data"`
	Port int    `json:"port"`
}

// fixture reads captured packets from a JSONL file.
func fixture(t *testing.T, name string) []packet {
	t.Helper()
	f, err := os.Open(name)
	require.NoError(t, err)
	defer f.Close()

	var ps []packet
	s := bufio.NewScanner(f)
	for s.Scan() {
		var p packet
		require.NoError(t, json.Unmarshal(s.Bytes(), &p))
		ps = append(ps, p)
	}
	require.NoError(t, s.Err())
	return ps
}

func TestDecodeKeepAlive(t *testing.T) {
	a := assert.New(t)
	r := require.New(t)

	var got []KeepAlive
	for _, p := range fixture(t, "testdata/keepalive.jsonl") {
		if p.Port != 50000 {
			continue
		}
		b, err := hex.DecodeString(p.Data)
		r.NoError(err)
		k, err := DecodeKeepAlive(b)
		r.NoError(err)
		got = append(got, k)
	}

	r.NotEmpty(got)
	k := got[0]
	a.Equal("CDJ-3000", k.Name)
	a.Equal(byte(3), k.Device)
	a.Equal("192.168.0.192", k.IP.String())
	a.Equal("c8:3d:fc:11:26:c2", k.MAC.String())
}


File created successfully at: /Users/noah/conductor/workspaces/deadca7/san-diego/link/packet_test.go (file state is current in your context — no need to Read it back)

package link

import (
	"bufio"
	"encoding/hex"
	"encoding/json"
	"os"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// packet mirrors a record written by cmd/capture.
type packet struct {
	Data string `json:"data"`
	Port int    `json:"port"`
}

// fixture reads captured packets from a JSONL file.
func fixture(t *testing.T, name string) []packet {
	t.Helper()
	f, err := os.Open(name)
	require.NoError(t, err)
	defer f.Close()

	var ps []packet
	s := bufio.NewScanner(f)
	for s.Scan() {
		var p packet
		require.NoError(t, json.Unmarshal(s.Bytes(), &p))
		ps = append(ps, p)
	}
	require.NoError(t, s.Err())
	return ps
}

func TestDecodeKeepAlive(t *testing.T) {
	a := assert.New(t)
	r := require.New(t)

	var got []KeepAlive
	for _, p := range fixture(t, "testdata/keepalive.jsonl") {
		if p.Port != 50000 {
			continue
		}
		b, err := hex.DecodeString(p.Data)
		r.NoError(err)
		k, err := DecodeKeepAlive(b)
		r.NoError(err)
		got = append(got, k)
	}

	r.NotEmpty(got)
	k := got[0]
	a.Equal("CDJ-3000", k.Name)
	a.Equal(byte(3), k.Device)
	a.Equal("192.168.0.192", k.IP.String())
	a.Equal("c8:3d:fc:11:26:c2", k.MAC.String())
}


Bash

go mod tidy >/dev/null 2>&1; go test ./... 2>&1 | tail -20

Run link module tests


ok  	github.com/nzoschke/deadca7/link	0.212s
?   	github.com/nzoschke/deadca7/link/cmd/capture	[no test files]


The test is working end-to-end with the real fixture, so now I'm creating a TODO.md file to track which protocol components have been captured and tested, organized by the beat-link and crate-digger sides.


Full loop works against the real fixture: **capture → JSONL → decode → assert**, no hardware needed at test time. Now the `TODO.md` checklist.


Write

# link TODO

Go port of Pioneer Pro DJ Link, built capture-first: document each packet,
capture a real fixture from the CDJ-3000, then decode it under test. No test
should require live hardware — `cmd/capture` records fixtures into `testdata/`.

## Setup

- CDJ-3000 at `192.168.0.192`, this Mac at `192.168.0.160` (en0), one `/24`.
- Reference SD card loaded in the CDJ for the database (crate-digger) flows.
- Passive capture: `go run ./cmd/capture -out testdata/<name>.jsonl -secs 8`.
- Active flows need a virtual CDJ that announces first — see Announce below.
  RPC/NFS uses dynamic ports, so capture those with `tcpdump` alongside.

## beat-link — live network protocol (UDP)

Each packet starts with Magic `51 73 70 74 31 57 6d 4a 4f 4c` + a type byte
read together with the port.

### Discovery / keep-alive — port 50000
- [x] keep-alive (type 0x06): name, device #, IP, MAC — `testdata/keepalive.jsonl`
- [ ] mixer/gateway packet seen on 50002 (type 0x40, "NXS-GW") — identify & decode
- [ ] full announce/channel-negotiation handshake (claim device # 1-4)
- [ ] virtual CDJ Announce + KeepAlive sender (prereq for all active flows)

### Beat sync — port 50001
- [ ] beat packet (type 0x28): BPM, beat-within-bar, pitch, next/prev beat timing
- [ ] capture across a tempo change and a loaded vs. stopped deck

### Status — port 50002
- [ ] CDJ status (type 0x0a): play state, BPM, pitch, on-air, master, sync
- [ ] loaded-track fields: track ID, source player, source slot (SD/USB)
- [ ] mixer status (DJM) if present
- [ ] capture scenarios: idle, track loaded, playing, two-deck, on-air toggle

## crate-digger — rekordbox database (over NFS)

Reached only after the virtual CDJ announces and a deck reports a loaded track.

- [ ] RPC portmap (port 111) — GETPORT for mount + nfs
- [ ] MOUNT — mount the media slot, obtain root file handle
- [ ] NFS — LOOKUP + READ `PIONEER/rekordbox/export.pdb`
- [ ] PDB parse: tables (tracks, artists, albums, artwork, playlists)
- [ ] ANLZ parse: `.DAT`/`.EXT` (beat grid, cue points, waveforms)
- [ ] metadata-by-track-ID resolved against captured PDB

## Reliability (port the vizlab code without its known bugs)

- [ ] replace `time.Sleep(5s)` FIXME in `Start()` with discovery/mount readiness
- [ ] make the media query deterministic (vizlab's was "unreliable")
- [ ] swap `github.com/pkg/errors` → `github.com/cockroachdb/errors`
- [ ] live integration suite gated behind `testing.Short()` / env, separate from
      the hermetic fixture-replay tests


File created successfully at: /Users/noah/conductor/workspaces/deadca7/san-diego/link/TODO.md (file state is current in your context — no need to Read it back)

# link TODO

Go port of Pioneer Pro DJ Link, built capture-first: document each packet,
capture a real fixture from the CDJ-3000, then decode it under test. No test
should require live hardware — `cmd/capture` records fixtures into `testdata/`.

## Setup

- CDJ-3000 at `192.168.0.192`, this Mac at `192.168.0.160` (en0), one `/24`.
- Reference SD card loaded in the CDJ for the database (crate-digger) flows.
- Passive capture: `go run ./cmd/capture -out testdata/<name>.jsonl -secs 8`.
- Active flows need a virtual CDJ that announces first — see Announce below.
  RPC/NFS uses dynamic ports, so capture those with `tcpdump` alongside.

## beat-link — live network protocol (UDP)

Each packet starts with Magic `51 73 70 74 31 57 6d 4a 4f 4c` + a type byte
read together with the port.

### Discovery / keep-alive — port 50000
- [x] keep-alive (type 0x06): name, device #, IP, MAC — `testdata/keepalive.jsonl`
- [ ] mixer/gateway packet seen on 50002 (type 0x40, "NXS-GW") — identify & decode
- [ ] full announce/channel-negotiation handshake (claim device # 1-4)
- [ ] virtual CDJ Announce + KeepAlive sender (prereq for all active flows)

### Beat sync — port 50001
- [ ] beat packet (type 0x28): BPM, beat-within-bar, pitch, next/prev beat timing
- [ ] capture across a tempo change and a loaded vs. stopped deck

### Status — port 50002
- [ ] CDJ status (type 0x0a): play state, BPM, pitch, on-air, master, sync
- [ ] loaded-track fields: track ID, source player, source slot (SD/USB)
- [ ] mixer status (DJM) if present
- [ ] capture scenarios: idle, track loaded, playing, two-deck, on-air toggle

## crate-digger — rekordbox database (over NFS)

Reached only after the virtual CDJ announces and a deck reports a loaded track.

- [ ] RPC portmap (port 111) — GETPORT for mount + nfs
- [ ] MOUNT — mount the media slot, obtain root file handle
- [ ] NFS — LOOKUP + READ `PIONEER/rekordbox/export.pdb`
- [ ] PDB parse: tables (tracks, artists, albums, artwork, playlists)
- [ ] ANLZ parse: `.DAT`/`.EXT` (beat grid, cue points, waveforms)
- [ ] metadata-by-track-ID resolved against captured PDB

## Reliability (port the vizlab code without its known bugs)

- [ ] replace `time.Sleep(5s)` FIXME in `Start()` with discovery/mount readiness
- [ ] make the media query deterministic (vizlab's was "unreliable")
- [ ] swap `github.com/pkg/errors` → `github.com/cockroachdb/errors`
- [ ] live integration suite gated behind `testing.Short()` / env, separate from
      the hermetic fixture-replay tests


I need to verify the workspace still builds since I've added new files to the link module. Let me run a build check across both the link and app modules using go.work to make sure everything compiles together.


Let me confirm the broader workspace still builds (the existing `link.go` share-link is untouched, so `app` should be fine) and vet the new code.


Bash

cd /Users/noah/conductor/workspaces/deadca7/san-diego && go build ./app/... ./link/... 2>&1 | tail; echo "build exit=$?"; cd link && go vet ./... 2>&1 | tail; echo "vet exit=$?"

Build app and link, vet link


go: downloading github.com/jackc/pgx/v5 v5.9.2
go: downloading github.com/gorilla/schema v1.4.1
go: downloading github.com/gabriel-vasile/mimetype v1.4.11
go: downloading github.com/oasdiff/yaml v0.0.9
go: downloading github.com/woodsbury/decimal128 v1.4.0
go: downloading github.com/mailru/easyjson v0.9.1
go: downloading github.com/oasdiff/yaml3 v0.0.9
go: downloading modernc.org/libc v1.72.3
go: downloading github.com/mattn/go-isatty v0.0.21
app/ui/assets/embed.go:5:12: pattern css/output.css: no matching files found
build exit=0
vet exit=0


The build error about the missing CSS file is a pre-existing issue with the Tailwind output not being generated, not something I introduced. My link module builds and vets successfully, which is what matters for my changes.


Done. The `app` build warning (`css/output.css: no matching files`) is a pre-existing generated-asset thing (tailwind output isn't built in this workspace) — unrelated to `link`, which builds, vets, and tests clean.

## What I built

Scaffolded the `link` module as a capture-first port, and proved the full loop works end-to-end against your live CDJ-3000:

```
link/
├── TODO.md                      # protocol capture/test checklist
├── cmd/capture/main.go          # passive UDP recorder → JSONL fixtures
├── packet.go                    # Magic, Type, DecodeKeepAlive
├── packet_test.go               # replays fixture, asserts decoded fields
└── testdata/keepalive.jsonl     # real capture from 192.168.0.192
```

- **Capture tool** (`cmd/capture`) listens on 50000/50001/50002 and writes one datagram per JSONL line, so tests never need hardware.
- **Real fixture captured** — 7 packets in 6s, including the `CDJ-3000` keep-alive (and a `0x40` "NXS-GW" packet on 50002, noted as a TODO to identify).
- **Decoder + test**: `DecodeKeepAlive` pulls name/device#/IP/MAC; `TestDecodeKeepAlive` replays the fixture and asserts `CDJ-3000`, device 3, `192.168.0.192`, `c8:3d:fc:11:26:c2`. Passes.
- **`TODO.md`** lists what to capture and test next, split into **beat-link** (discovery/keep-alive ✅, announce handshake, beat sync 50001, status 50002) and **crate-digger** (RPC portmap → mount → NFS → PDB → ANLZ), plus a reliability section targeting the vizlab bugs (the `time.Sleep(5s)` FIXME, the unreliable media query, `pkg/errors`→`cockroachdb/errors`, hardware-gated tests).

I left the existing `link.go` share-link code in place so this branch builds — your other PR relocates it to `app`.

The clear next step (per `TODO.md`) is the **virtual-CDJ announce sender**, since it unlocks every active flow (status, metadata, NFS). Want me to take that next, or capture more passive scenarios (beat 50001, the 0x40 packet) first?


the mixer is on now too capture packets from it ?


The mixer is now online too, so I need to capture packets from it as well. Let me run a packet capture to see what devices show up — the DJM mixer should be broadcasting keep-alives on port 50000 just like the other equipment. I'll capture over a longer window to get a clearer picture, then analyze the data by source IP and device name to build a complete inventory of what's on the network.


The mixer should announce on 50000 like the CDJ. Let me capture a fresh window and see what devices show up.


cd /Users/noah/conductor/workspaces/deadca7/san-diego/link && go run ./cmd/capture -out testdata/devices.jsonl -secs 8 2>&1; echo "---SUMMARY (src / port / type / name)---"; python3 -c '
import json,collections
seen=collections.OrderedDict()
for line in open("testdata/devices.jsonl"):
    p=json.loads(line); d=bytes.fromhex(p["data"])
    magic=d[:10]==bytes([0x51,0x73,0x70,0x74,0x31,0x57,0x6d,0x4a,0x4f,0x4c])
    typ=d[0x0a] if magic and len(d)>0x0a else None
    name=d[0x0c:0x20].rstrip(b"\x00").decode("latin1","replace") if magic and len(d)>0x20 else ""
    key=(p["src"].split(":")[0],p["port"],typ)
    seen.setdefault(key,[name,0,p["len"]]); seen[key][1]+=1
for (src,port,typ),(name,cnt,ln) in seen.items():
    t=f"0x{typ:02x}" if typ is not None else "??"
    print(f"{src:15} port={port} type={t} name={name!r:12} count={cnt} len={ln}")
'

Capture and summarize all DJ Link devices


captured 37 packets to testdata/devices.jsonl
---SUMMARY (src / port / type / name)---
192.168.0.193   port=50001 type=0x03 name='JM-V10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01' count=25 len=53
192.168.0.192   port=50000 type=0x06 name='CDJ-3000'   count=4 len=54
192.168.0.192   port=50002 type=0x40 name='XS-GW\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01' count=4 len=38
192.168.0.193   port=50000 type=0x06 name='DJM-V10'    count=4 len=54


 Looking at the DJM-V10 mixer at 192.168.0.193, I'm seeing two different broadcast types on separate ports — a keep-alive on port 50000 and what appears to be a different packet structure on port 50001 with 25 packets of 53 bytes each. The name parsing is tricky here since the offset where I'd expect to find the device name doesn't align with what I'm seeing, suggesting the packet layout for type 0x03 differs from what I initially assumed.

I need to verify that the DJM-V10 keep-alive actually decodes correctly with the existing decoder, and then examine the raw bytes of a type 0x03 packet to understand its structure. I'll also want to update the test fixtures to include both the CDJ and mixer devices, so I can confirm both are properly discovered and decoded.


The DJM-V10 mixer is now on the network at `192.168.0.193`. Let me verify its keep-alive decodes cleanly and inspect that frequent type `0x03` it's sending on the beat port (50001).


python3 -c '
import json
def find(port,typ,src=None):
    for line in open("testdata/devices.jsonl"):
        p=json.loads(line); d=bytes.fromhex(p["data"])
        if p["port"]==port and len(d)>0x0a and d[0x0a]==typ and (src is None or p["src"].startswith(src)):
            return d
# DJM-V10 keepalive fields (same layout as CDJ keepalive)
k=find(50000,0x06,"192.168.0.193")
print("DJM-V10 keepalive:")
print("  name  ", k[0x0c:0x20].rstrip(b"\x00").decode())
print("  device", k[0x24])
print("  ip    ", ".".join(str(b) for b in k[0x2c:0x30]))
print("  mac   ", ":".join("%02x"%b for b in k[0x26:0x2c]))
# the 50001 type 0x03 packet
b=find(50001,0x03)
print("\n50001 type=0x03 (len %d):"%len(b))
print(" ",b.hex())
print("  name@0x0b", b[0x0b:0x0b+20].rstrip(b"\x00").decode("latin1"))
print("  byte 0x1f..end:", b[0x1f:].hex())
'

Decode DJM keepalive and inspect 0x03 packet


DJM-V10 keepalive:
  name   DJM-V10
  device 33
  ip     192.168.0.193
  mac    c8:3d:fc:12:9e:d5

50001 type=0x03 (len 53):
  5173707431576d4a4f4c03444a4d2d5631300000000000000000000000000001032100110000000000000000000000000000000000
  name@0x0b DJM-V10
  byte 0x1f..end: 01032100110000000000000000000000000000000000


 The DJM-V10 keepalive packet decodes successfully with the existing decoder, revealing device 33 at IP 192.168.0.193 with MAC c8:3d:fc:12:9e:d5—notably, device 33 corresponds to mixer channel numbering, confirming the decoder handles mixer devices properly. Now I'm looking at what's in that 50001 type 0x03 packet.

The name field starts at offset 0x0b (not 0x0c like the keepalive), showing "DJM-V10" followed by nulls, with the packet structure being magic (10 bytes) + type 0x03 + name (20 bytes) + device number 0x01 + some unknown bytes. The 0x21 offset contains 33 (matching the device number), and 0x11 might be a payload length field. This 0x03 packet is likely a mixer status or on-air channels announcement, but I'll note it as unidentified for now rather than guess its purpose.

I should consolidate the test fixtures—devices.jsonl now contains everything I need, so I'll make the test table-driven to verify both the CDJ-3000 (device 3, MAC c8:3d:fc:11:26:c2) and DJM-V10 (device 33, MAC c8:3d:fc:12:9e:d5) are discovered, then remove the redundant keepalive.jsonl file and update the test accordingly.


The mixer decodes cleanly with the same keep-alive parser — `DJM-V10`, device **33** (mixers claim channel 33+), `192.168.0.193`, MAC `c8:3d:fc:12:9e:d5`. And I learned something useful: the type `0x03` packet the mixer streams on 50001 (~3/s) puts the device name at offset `0x0b`, not `0x0c` like keep-alives — a different framing to decode later.

Let me consolidate to a single multi-device discovery fixture, make the test table-driven over both devices, and drop the now-redundant single fixture.


Write

package link

import (
	"bufio"
	"encoding/hex"
	"encoding/json"
	"os"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// packet mirrors a record written by cmd/capture.
type packet struct {
	Data string `json:"data"`
	Port int    `json:"port"`
}

// fixture reads captured packets from a JSONL file.
func fixture(t *testing.T, name string) []packet {
	t.Helper()
	f, err := os.Open(name)
	require.NoError(t, err)
	defer f.Close()

	var ps []packet
	s := bufio.NewScanner(f)
	for s.Scan() {
		var p packet
		require.NoError(t, json.Unmarshal(s.Bytes(), &p))
		ps = append(ps, p)
	}
	require.NoError(t, s.Err())
	return ps
}

func TestDecodeKeepAlive(t *testing.T) {
	r := require.New(t)

	got := map[string]KeepAlive{}
	for _, p := range fixture(t, "testdata/devices.jsonl") {
		if p.Port != 50000 {
			continue
		}
		b, err := hex.DecodeString(p.Data)
		r.NoError(err)
		k, err := DecodeKeepAlive(b)
		r.NoError(err)
		got[k.Name] = k
	}

	want := []KeepAlive{
		{Device: 3, IP: net.ParseIP("192.168.0.192"), MAC: mac(t, "c8:3d:fc:11:26:c2"), Name: "CDJ-3000"},
		{Device: 33, IP: net.ParseIP("192.168.0.193"), MAC: mac(t, "c8:3d:fc:12:9e:d5"), Name: "DJM-V10"},
	}
	for _, w := range want {
		t.Run(w.Name, func(t *testing.T) {
			a := assert.New(t)
			k, ok := got[w.Name]
			a.True(ok)
			a.Equal(w.Device, k.Device)
			a.Equal(w.IP.String(), k.IP.String())
			a.Equal(w.MAC.String(), k.MAC.String())
		})
	}
}

func mac(t *testing.T, s string) net.HardwareAddr {
	t.Helper()
	m, err := net.ParseMAC(s)
	require.NoError(t, err)
	return m
}


The file /Users/noah/conductor/workspaces/deadca7/san-diego/link/packet_test.go has been updated successfully. (file state is current in your context — no need to Read it back)

package link

import (
	"bufio"
	"encoding/hex"
	"encoding/json"
	"os"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// packet mirrors a record written by cmd/capture.
type packet struct {
	Data string `json:"data"`
	Port int    `json:"port"`
}

// fixture reads captured packets from a JSONL file.
func fixture(t *testing.T, name string) []packet {
	t.Helper()
	f, err := os.Open(name)
	require.NoError(t, err)
	defer f.Close()

	var ps []packet
	s := bufio.NewScanner(f)
	for s.Scan() {
		var p packet
		require.NoError(t, json.Unmarshal(s.Bytes(), &p))
		ps = append(ps, p)
	}
	require.NoError(t, s.Err())
	return ps
}

func TestDecodeKeepAlive(t *testing.T) {
	r := require.New(t)

	got := map[string]KeepAlive{}
	for _, p := range fixture(t, "testdata/devices.jsonl") {
		if p.Port != 50000 {
			continue
		}
		b, err := hex.DecodeString(p.Data)
		r.NoError(err)
		k, err := DecodeKeepAlive(b)
		r.NoError(err)
		got[k.Name] = k
	}

	want := []KeepAlive{
		{Device: 3, IP: net.ParseIP("192.168.0.192"), MAC: mac(t, "c8:3d:fc:11:26:c2"), Name: "CDJ-3000"},
		{Device: 33, IP: net.ParseIP("192.168.0.193"), MAC: mac(t, "c8:3d:fc:12:9e:d5"), Name: "DJM-V10"},
	}
	for _, w := range want {
		t.Run(w.Name, func(t *testing.T) {
			a := assert.New(t)
			k, ok := got[w.Name]
			a.True(ok)
			a.Equal(w.Device, k.Device)
			a.Equal(w.IP.String(), k.IP.String())
			a.Equal(w.MAC.String(), k.MAC.String())
		})
	}
}

func mac(t *testing.T, s string) net.HardwareAddr {
	t.Helper()
	m, err := net.ParseMAC(s)
	require.NoError(t, err)
	return m
}

-  for _, p := range fixture(t, "testdata/keepalive.jsonl") {

+  for _, p := range fixture(t, "testdata/devices.jsonl") {

+      a.Equal(w.IP.String(), k.IP.String())

+      a.Equal(w.MAC.String(), k.MAC.String())

+func mac(t *testing.T, s string) net.HardwareAddr {

package link

import (
	"bufio"
	"encoding/hex"
	"encoding/json"
	"os"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// packet mirrors a record written by cmd/capture.
type packet struct {
	Data string `json:"data"`
	Port int    `json:"port"`
}

// fixture reads captured packets from a JSONL file.
func fixture(t *testing.T, name string) []packet {
	t.Helper()
	f, err := os.Open(name)
	require.NoError(t, err)
	defer f.Close()

	var ps []packet
	s := bufio.NewScanner(f)
	for s.Scan() {
		var p packet
		require.NoError(t, json.Unmarshal(s.Bytes(), &p))
		ps = append(ps, p)
	}
	require.NoError(t, s.Err())
	return ps
}

func TestDecodeKeepAlive(t *testing.T) {
	a := assert.New(t)
	r := require.New(t)

	var got []KeepAlive
	for _, p := range fixture(t, "testdata/keepalive.jsonl") {
		if p.Port != 50000 {
			continue
		}
		b, err := hex.DecodeString(p.Data)
		r.NoError(err)
		k, err := DecodeKeepAlive(b)
		r.NoError(err)
		got = append(got, k)
	}

	r.NotEmpty(got)
	k := got[0]
	a.Equal("CDJ-3000", k.Name)
	a.Equal(byte(3), k.Device)
	a.Equal("192.168.0.192", k.IP.String())
	a.Equal("c8:3d:fc:11:26:c2", k.MAC.String())
}


I need to add the "net" import since I'm using net.ParseIP and net.HardwareAddr, and also remove the keepalive.jsonl file.


Edit

	"encoding/json"
	"net"
	"os"
	"testing"


	"encoding/json"
	"net"
	"os"
	"testing"

package link

import (
	"bufio"
	"encoding/hex"
	"encoding/json"
	"os"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// packet mirrors a record written by cmd/capture.
type packet struct {
	Data string `json:"data"`
	Port int    `json:"port"`
}

// fixture reads captured packets from a JSONL file.
func fixture(t *testing.T, name string) []packet {
	t.Helper()
	f, err := os.Open(name)
	require.NoError(t, err)
	defer f.Close()

	var ps []packet
	s := bufio.NewScanner(f)
	for s.Scan() {
		var p packet
		require.NoError(t, json.Unmarshal(s.Bytes(), &p))
		ps = append(ps, p)
	}
	require.NoError(t, s.Err())
	return ps
}

func TestDecodeKeepAlive(t *testing.T) {
	r := require.New(t)

	got := map[string]KeepAlive{}
	for _, p := range fixture(t, "testdata/devices.jsonl") {
		if p.Port != 50000 {
			continue
		}
		b, err := hex.DecodeString(p.Data)
		r.NoError(err)
		k, err := DecodeKeepAlive(b)
		r.NoError(err)
		got[k.Name] = k
	}

	want := []KeepAlive{
		{Device: 3, IP: net.ParseIP("192.168.0.192"), MAC: mac(t, "c8:3d:fc:11:26:c2"), Name: "CDJ-3000"},
		{Device: 33, IP: net.ParseIP("192.168.0.193"), MAC: mac(t, "c8:3d:fc:12:9e:d5"), Name: "DJM-V10"},
	}
	for _, w := range want {
		t.Run(w.Name, func(t *testing.T) {
			a := assert.New(t)
			k, ok := got[w.Name]
			a.True(ok)
			a.Equal(w.Device, k.Device)
			a.Equal(w.IP.String(), k.IP.String())
			a.Equal(w.MAC.String(), k.MAC.String())
		})
	}
}

func mac(t *testing.T, s string) net.HardwareAddr {
	t.Helper()
	m, err := net.ParseMAC(s)
	require.NoError(t, err)
	return m
}

"bufio"
"encoding/hex"
"encoding/json"
+  "net"
"os"
"testing"


Bash

rm -f testdata/keepalive.jsonl && go test ./... 2>&1 | tail -15

Remove old fixture, run tests


ok  	github.com/nzoschke/deadca7/link	0.214s
?   	github.com/nzoschke/deadca7/link/cmd/capture	[no test files]


Now update `TODO.md` to reflect the mixer capture and the new `0x03` finding.


The file /Users/noah/conductor/workspaces/deadca7/san-diego/link/TODO.md has been updated successfully. (file state is current in your context — no need to Read it back)

# link TODO

Go port of Pioneer Pro DJ Link, built capture-first: document each packet,
capture a real fixture from the CDJ-3000, then decode it under test. No test
should require live hardware — `cmd/capture` records fixtures into `testdata/`.

## Setup

- CDJ-3000 at `192.168.0.192`, this Mac at `192.168.0.160` (en0), one `/24`.
- Reference SD card loaded in the CDJ for the database (crate-digger) flows.
- Passive capture: `go run ./cmd/capture -out testdata/<name>.jsonl -secs 8`.
- Active flows need a virtual CDJ that announces first — see Announce below.
  RPC/NFS uses dynamic ports, so capture those with `tcpdump` alongside.

## beat-link — live network protocol (UDP)

Each packet starts with Magic `51 73 70 74 31 57 6d 4a 4f 4c` + a type byte
read together with the port.

### Discovery / keep-alive — port 50000
- [x] keep-alive (type 0x06): name, device #, IP, MAC — `testdata/keepalive.jsonl`
- [ ] mixer/gateway packet seen on 50002 (type 0x40, "NXS-GW") — identify & decode
- [ ] full announce/channel-negotiation handshake (claim device # 1-4)
- [ ] virtual CDJ Announce + KeepAlive sender (prereq for all active flows)

### Beat sync — port 50001
- [ ] beat packet (type 0x28): BPM, beat-within-bar, pitch, next/prev beat timing
- [ ] capture across a tempo change and a loaded vs. stopped deck

### Status — port 50002
- [ ] CDJ status (type 0x0a): play state, BPM, pitch, on-air, master, sync
- [ ] loaded-track fields: track ID, source player, source slot (SD/USB)
- [ ] mixer status (DJM) if present
- [ ] capture scenarios: idle, track loaded, playing, two-deck, on-air toggle

## crate-digger — rekordbox database (over NFS)

Reached only after the virtual CDJ announces and a deck reports a loaded track.

- [ ] RPC portmap (port 111) — GETPORT for mount + nfs
- [ ] MOUNT — mount the media slot, obtain root file handle
- [ ] NFS — LOOKUP + READ `PIONEER/rekordbox/export.pdb`
- [ ] PDB parse: tables (tracks, artists, albums, artwork, playlists)
- [ ] ANLZ parse: `.DAT`/`.EXT` (beat grid, cue points, waveforms)
- [ ] metadata-by-track-ID resolved against captured PDB

## Reliability (port the vizlab code without its known bugs)

- [ ] replace `time.Sleep(5s)` FIXME in `Start()` with discovery/mount readiness
- [ ] make the media query deterministic (vizlab's was "unreliable")
- [ ] swap `github.com/pkg/errors` → `github.com/cockroachdb/errors`
- [ ] live integration suite gated behind `testing.Short()` / env, separate from
      the hermetic fixture-replay tests


Edit

### Discovery / keep-alive — port 50000
- [x] keep-alive (type 0x06): name, device #, IP, MAC — `testdata/keepalive.jsonl`
- [ ] mixer/gateway packet seen on 50002 (type 0x40, "NXS-GW") — identify & decode
- [ ] full announce/channel-negotiation handshake (claim device # 1-4)
- [ ] virtual CDJ Announce + KeepAlive sender (prereq for all active flows)

### Beat sync — port 50001
- [ ] beat packet (type 0x28): BPM, beat-within-bar, pitch, next/prev beat timing
- [ ] capture across a tempo change and a loaded vs. stopped deck

### Discovery / keep-alive — port 50000
- [x] keep-alive (type 0x06): name, device #, IP, MAC — `testdata/devices.jsonl`
      covers CDJ-3000 (device 3) and DJM-V10 (device 33); name at 0x0c
- [ ] mixer/gateway packet seen on 50002 (type 0x40, "NXS-GW") — identify & decode
- [ ] full announce/channel-negotiation handshake (claim device # 1-4)
- [ ] virtual CDJ Announce + KeepAlive sender (prereq for all active flows)

### Beat sync — port 50001
- [ ] beat packet (type 0x28): BPM, beat-within-bar, pitch, next/prev beat timing
- [ ] mixer type 0x03 (~3/s from DJM-V10, name at 0x0b not 0x0c) — identify & decode
- [ ] capture across a tempo change and a loaded vs. stopped deck