codegraph/telemetry-worker

codegraph telemetry ingest worker

The first-party endpoint behind telemetry.getcodegraph.com. This directory is in the public repo on purpose: it is the exact code that receives codegraph's anonymous usage telemetry, so anyone can audit what is stored. The schema contract (every event, every field, and everything that is never collected) is in docs/design/telemetry.md.

What it does, in one breath: validates incoming batches against a strict allowlist (unknown events dropped, unknown properties stripped), never reads or forwards the client IP, rate-limits per machine ID, and forwards to PostHog off the response path. It ships nowhere with the npm package — the engine's files allowlist excludes it.

Endpoint contract

• POST /v1/events — JSON body: envelope (machine_id UUID, codegraph_version, os, arch, node_major, ci, schema_version) + events: [{event, ts?, props?}]. Responds 204 when accepted (including events dropped by the allowlist), honest 4xx for malformed/oversized/rate-limited requests. Clients treat every response as final — no retries.
• GET / — plain-text pointer to the docs and the off-switches.

Storage (Cloudflare D1)

Telemetry is stored in the codegraph-telemetry D1 database on the same account, bound as env.DB. The complete schema is migrations/0001_init.sql — checked in for the same reason this worker's source is public: it is the entire list of what gets kept, with a comment on every column and on which dashboard chart each rollup table serves. Shape: raw sanitized events, daily_* rollups recomputed nightly, and machine_days / machine_first_seen for retention cohorts. The dashboard reads rollups; raw events exist for drill-down and are purged past the retention window.

npm run db:migrate:local     # apply to the local .wrangler state (offline, no account needed)
npm run db:migrate           # apply to the remote codegraph-telemetry database
npm run db:migrations        # which migrations are applied remotely
npm run db:sql "select count(*) from events"

Both applies bootstrap from empty and are a no-op when already current. A schema change is a new numbered file (npx wrangler d1 migrations create codegraph-telemetry <name>) — never an edit to a migration that has been applied.

Volume, at ~97k accepted POSTs/day: ≈30M D1 row writes/month against the 50M included on Workers Paid. D1 bills a row write per index touched on top of the table row, which is why events carries only two indexes. Storage is the tighter constraint — raw events grow ≈74 MB/day, so a 90-day retention window lands at ≈6.7 GB against D1's 10 GB per-database cap, while 180 days would exceed it. Rollups are tiny and kept forever, so shortening the raw window costs drill-back, never a chart. Full arithmetic and the levers are in the migration's footer comment.

Deploy

Prereqs: the getcodegraph.com zone on the deploying Cloudflare account (the custom domain route auto-provisions DNS + cert), wrangler ≥ 4.36 (the ratelimits binding).

cd telemetry-worker
npm install
npx wrangler login                      # once
npx wrangler secret put POSTHOG_KEY     # the phc_… project write key — never committed
npm run db:migrate                      # bring the D1 schema up to date first
npm run deploy

The PostHog project itself must have "Discard client IP data" enabled — defense in depth on top of this worker never forwarding IPs ($geoip_disable is also set per event).

Local dev & checks

cp .dev.vars.example .dev.vars   # placeholder key; also feeds `wrangler types`
npm run check                    # wrangler types + tsc --noEmit + deploy --dry-run
npm run dev                      # http://localhost:8787

curl -i localhost:8787/v1/events -H 'content-type: application/json' -d '{
  "machine_id": "00000000-0000-4000-8000-000000000000",
  "codegraph_version": "0.9.9", "os": "darwin", "arch": "arm64",
  "node_major": 22, "ci": false, "schema_version": 1,
  "events": [{ "event": "usage_rollup",
               "props": { "kind": "mcp_tool", "name": "codegraph_explore",
                          "count": 12, "error_count": 0, "client_name": "Claude Code" } }]
}'

Changing the schema

The allowlist in src/index.ts mirrors docs/design/telemetry.md (and the user-facing TELEMETRY.md). A field is added by one PR touching all of them together — that is the whole point of the design.