91 lines · 8.0 KB

Integrations

Repo admins manage integrations at /<owner>/<repo>/settings/integrations. Org owners manage them at /orgs/<org>/integrations, and org integrations receive events from every repo in the org.

How delivery works

  • Forge events (emitWebhook) are fanned out on the gitfor-integrations queue. Failed deliveries retry with exponential backoff (15 s doubling, capped at 1 h). After 7 attempts (6 retries) a delivery moves to gitfor-integrations-dlq and is marked dead in the delivery log.
  • Permanent failures (most 4xx, missing credentials, rejected URLs) are logged as failed and not retried.
  • Every outbound URL goes through assertPublicHttpsUrl (hostname rules) and then assertResolvesPublic (src/server/net/resolve-guard.ts), which does DNS-over-HTTPS A/AAAA lookups (following CNAMEs) and rejects private, loopback, link-local, CGNAT, metadata, multicast and reserved addresses, including IPv4-mapped, NAT64 and 6to4 forms. The check runs before every request; redirects are never followed. DoH outages fail closed with a retryable error.
  • TOCTOU: Workers' fetch() cannot pin a connection to the checked address, so a DNS-rebinding window remains between the lookup and Cloudflare's own resolution. Answers are cached for 60 s per isolate so repeated checks agree, and Workers egress cannot reach RFC 1918, loopback or metadata addresses anyway.
  • Deliveries are idempotent per (source event, integration): retried events reuse the same delivery row, and a short lease stops two consumers sending the same delivery. Slack bot posts track each channel, so a retry only resends to channels that failed. Relayed GitHub webhooks are keyed by X-GitHub-Delivery, so GitHub's own "Redeliver" of an already-processed delivery is ignored.
  • Each delivery is metered once when it reaches its final outcome (ops.integration_deliveries, per owning account, idempotency key integration:<deliveryId>) into integration_usage_daily until the usage-metering service lands.
  • Git imports and ref syncs (src/server/git/relay.ts) use the same DNS check on every hop, with no loopback escape. a 256 KB request cap and a 64 KB response cap.
  • Each payload is signed with the integration's secret in X-Gitfor-Signature-256: sha256=<hex HMAC>.
  • Credentials (webhook URLs, OAuth tokens, signing secrets) are stored AES-GCM encrypted with SECRETS_KEY.

Keeping noise down

Integrations are quiet by default:

  • Only pull requests and releases are on.
  • CI only reports failures.
  • Pushes and CI only report the default branch.
  • Drafts and bots are skipped.

Each integration has per-event toggles, branch globs, and a digest mode that batches events into one message every N minutes. The digest is flushed by the 5-minute cron.

Providers and secrets

Provider Secrets Notes
Slack SLACK_CLIENT_ID, SLACK_CLIENT_SECRET, SLACK_SIGNING_SECRET OAuth install (chat:write,commands,incoming-webhook) or a pasted incoming webhook. Each channel gets its own event filter. The slash command /gitfor status owner/repo is served at /integrations/hooks/slack/commands.
Google Chat none Paste a space webhook (chat.googleapis.com). Messages are sent as cardsV2.
Linear LINEAR_CLIENT_ID, LINEAR_CLIENT_SECRET Issue keys (ENG-123) in PR titles, branches and commits link PRs and commits to issues. On PR open, merge or close, the issue moves to the configured state, and is never moved backwards. A signed Linear webhook is registered automatically at /integrations/hooks/linear/<id>.
GitHub GITHUB_APP_ID, GITHUB_APP_SLUG, GITHUB_APP_PRIVATE_KEY, GITHUB_APP_CLIENT_ID, GITHUB_APP_CLIENT_SECRET, GITHUB_APP_WEBHOOK_SECRET Authenticates with GitHub App installation tokens only. Enable "Request user authorization during installation" so ownership of the installation can be verified. Supports a one-way mirror in either direction, a one-shot import of issues and PRs, and webhook relay. The app webhook URL is /integrations/hooks/github.
Webhook none Signed JSON with { event, summary, payload }.

Notes on the GitHub integration (for a token-based, bidirectional mirror with any forge, see mirroring.md):

  • The GitHub → gitfor mirror runs at most every 15 minutes, and also runs on each relayed GitHub push.
  • Mirrors cover branches and tags only.
  • Mirrors update and create refs but never delete them.
  • The GitHub → gitfor mirror goes through the same gates as a git push, acting as a write-permission pusher (the installing admin): hidden refs are never written, branch protection applies (so a branch that requires pull requests is never updated by the mirror, and a protected branch only accepts a non-fast-forward when its rule allows force pushes), and push protection scans for secrets. Applied refs fire normal push events, so CI, webhooks and integrations run.
  • By default the mirror is fast-forward only. Force mirror is an explicit per-integration admin opt-in that lets diverged unprotected branches be overwritten (it never relaxes push protection); enabling or disabling it (and changing the mirror direction) is recorded in the integration's audit log and shown in the UI. Refused refs are listed in the delivery log.
  • Only repositories that the installing GitHub user could access through the installation can be chosen.
  • PRs are imported as issues labelled pull-request, since their branches are not copied.
  • Re-running an import skips items that were already imported.

Local development and e2e

Add INTEGRATIONS_ALLOW_LOOPBACK=true to .dev.vars to allow http://localhost and 127.0.0.1 sinks. Never set it in production. Then run:

bun test src
E2E_BASE_URL=http://localhost:3000 bun run test:e2e:integrations

The e2e flow:

  1. Signs up and creates an org.
  2. Checks that a private-network URL is rejected.
  3. Adds a webhook integration that points at a local sink.
  4. Sends a test event and verifies its HMAC signature.
  5. Waits for the delivery log to show success, then redelivers.