JMR-devandClaude Opus 4.8 bd7fe21d97 #9 Encrypted-at-rest R2 storage for scrubbed reports
Implement the storage path: for each accepted report, scrub PII (#8),
encrypt with AES-256-GCM (ADR #5), and write only ciphertext to R2, wired
in as the real ingest Sink replacing NopSink.

- internal/crypto: AES-256-GCM in the exact ADR #5 wire format
  (magic "LMB1" || version || key_id BE16 || nonce(12) || ct || tag(16);
  the 7-byte header is the GCM AAD). Provider-independent framing shared by
  a host crypto/aes+crypto/cipher impl (tests, devserver) and a Wasm
  SubtleCrypto impl (syscall/js, //go:build js && wasm) per the TinyGo
  constraint; both produce byte-identical frames. Versioned keyring with
  key_id rotation; ParseKeyring reads the Secrets Store JSON secret.
- internal/storage: ObjectStore interface with an in-memory fake (tests,
  devserver) and a Wasm R2Store (syumai/workers R2 binding). Sink ties
  scrub -> Seal -> Put under a unique reports/<ts>-<rand> key. WorkerSink
  loads the keyring from Secrets Store (BUGREPORT_ENC_KEYRING), cached for
  the isolate lifetime.
- handler.New now takes an injectable ingest.Sink; the Worker uses the real
  R2/Secrets-Store sink, the devserver a memory + throwaway-key sink.
- wrangler.jsonc: add REPORTS_BUCKET (R2) and BUGREPORT_ENC_KEYRING
  (Secrets Store) bindings.

Tests (host, no TinyGo): encrypt/decrypt roundtrip; ciphertext != plaintext;
wrong key + tamper (ct/tag/nonce/header-AAD) fail; exact wire layout plus a
known-answer vector; key_id rotation with retained keys; full sink path (PII
scrubbed then encrypted, readback requires the key and yields the scrubbed
content). Existing ingest/handler behavior preserved (202 on valid POST).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-02 15:08:21 -05:00

LibreMail Bug Report Ingest

Server-side infrastructure for LibreMail's debug bug-report pipeline. This repo is intentionally separate from the Android app repo — it owns the Cloudflare Worker and infrastructure-as-code, not the client.

What this is

Per JMR-dev/LibreMail#11:

  1. The LibreMail app lets a user opt in to submitting a debug report (LibreMail#33).
  2. A Cloudflare Worker in this repo receives the report over HTTPS, best-effort scrubs PII, and stores it encrypted in a Cloudflare R2 bucket (#34).
  3. Every Friday at 17:00 (Central Time, DST-aware), a scheduled job publishes any report not manually removed as a GitHub issue on the LibreMail repo (#35).

Stack

  • Worker: Go, compiled to WebAssembly with TinyGo and served through the syumai/workers runtime adapter
  • Infrastructure as code: Pulumi (Go)
  • Deployment: GitHub Actions
  • Secrets/key custody: Cloudflare Secret Manager
  • DNS: Google Cloud DNS

Build & run locally

The request-handling logic lives in internal/handler as plain, build-tag-free Go, so it is unit-tested and run locally with the standard Go toolchain — no TinyGo needed. Only the actual Wasm Worker build requires TinyGo.

Layout:

  • internal/handler/ — the core http.Handler (health/hello endpoints). No build tags; all request logic and its tests live here.
  • cmd/devserver/ — a plain net/http server that mounts the core handler for local dev without TinyGo.
  • worker/ — the Cloudflare Workers (Wasm) entrypoint, guarded by //go:build js && wasm, wiring the same core handler into the Workers runtime. Excluded from host builds and tests.

Test

go vet ./...
go test ./...

Run locally (no TinyGo)

go run ./cmd/devserver   # listens on :8787; override with ADDR, e.g. ADDR=:9000

Then, from another shell:

$ curl -s localhost:8787/
{"service":"libremail-bug-report-ingest","status":"ok","message":"hello from the LibreMail bug-report ingest Worker"}
$ curl -s localhost:8787/healthz
{"status":"ok"}

This runs the exact handler the deployed Worker uses, minus the Workers runtime.

Build & run the real Worker (requires TinyGo)

Node tooling is managed with pnpm; wrangler is a dev dependency. The Wasm build uses TinyGo 0.41.1 on the Go 1.26 toolchain.

Temporary toolchain patch. TinyGo 0.41.1 and earlier vendor a net/http js/wasm overlay (tinygo-org/net@e54965e) that fails to compile against Go 1.25+/1.26 with t.roundTrip undefined (see tinygo-org/tinygo#5467). CI applies the exact upstream fix (tinygo-org/net@1026408a, checked in as .ci/tinygo-net-roundtrip.patch) to the installed TinyGo before building. Building locally on Go 1.26 needs the same one-file patch until a TinyGo release later than 0.41.1 ships it, at which point the patch and the CI step are removed (tracked in #26).

pnpm install                 # install wrangler
pnpm run build               # workers-assets-gen + TinyGo -> ./build/app.wasm + ./build/worker.mjs
pnpm exec wrangler dev       # serve the Wasm Worker locally on :8787
pnpm exec wrangler deploy    # deploy (CI only)

pnpm run build runs, verbatim:

go run github.com/syumai/workers/cmd/workers-assets-gen && tinygo build -o ./build/app.wasm -target wasm -no-debug ./worker

TinyGo is not required for tests or the dev server; it is needed only for the Wasm build above and is installed in CI. The generated ./build/ output is git-ignored.

Why TinyGo + syumai/workers

Cloudflare Workers execute WebAssembly, not native binaries, so Go must be compiled to Wasm. Of the two options — the standard compiler's GOOS=js GOARCH=wasm output or TinyGo — TinyGo emits far smaller modules that sit comfortably inside the Worker size limit, which is why it is the standard path for Go on Workers. The syumai/workers package adapts Go's net/http handler model to the Workers fetch event, so a single http.Handler runs unchanged on the dev server and in the deployed Worker.

Status

Early bootstrap. See the project board and open issues for the current breakdown of work.

License

GNU AGPL v3.0.

S
Description
Server-side ingest pipeline (Cloudflare Worker + IaC) for LibreMail's opt-in bug-report feature. See JMR-dev/LibreMail#11.
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