provide-uterm-cloudflare

Cloudflare Workers companion package for provide-uterm. Runs the provide-uterm control plane on Cloudflare Workers using Durable Objects, with a fleet-wide session registry backed by Workers KV.

What it does

Each terminal session gets its own Durable Object (SessionRuntime). The DO arbitrates WebSocket traffic between the runtime worker connector and browser clients, stores hijack leases and snapshots in SQLite, and publishes events to all connected browsers. A fleet-wide session list is maintained in Workers KV.

Installation

pip install provide-uterm-cloudflare

Or install from the monorepo with uv:

uv pip install -e packages/provide-uterm-cloudflare

Deploy

The worker entrypoint is src/worker_entry.py (referenced by main in wrangler.toml). It lives at the package src/ root on purpose: wrangler bundles the directory of the main file, so anchoring it there preserves the full provide/uterm/cloudflare/ tree in the bundle and the worker's qualified imports resolve as-is.

The Pyodide runtime also needs a flat vendor tree of the pure-Python deps the worker imports (structlog, provide.telemetry, and the provide.uterm.* modules). pywrangler sync produces a layout the worker can't import, so build it with the helper script, then deploy with wrangler directly (not pywrangler deploy, which would re-sync and overwrite the tree):

bash .ci/vendor_cf_worker.sh                          # build python_modules/
cd packages/provide-uterm-cloudflare
CLOUDFLARE_API_TOKEN=… npx wrangler deploy            # publish

# Required secrets (AUTH_MODE is jwt-only; the worker 500s without these):
npx wrangler secret put WORKER_BEARER_TOKEN           # >=32 high-entropy chars
npx wrangler secret put WEBHOOK_SECRET_KEY            # base64 AES-256 key

Key features

• Durable Object per session — SessionRuntime DO holds all session state (leases, snapshots, event sequence) in SQLite.
• Fleet-wide session registry — SESSION_REGISTRY Workers KV namespace; GET /api/sessions returns all active sessions across the fleet.
• CF Access JWT auth — validates Cloudflare Access JWTs via JWKS; JWT_DEFAULT_ROLE env var assigns a role when the JWT carries no role claim.
• Hijack REST API — POST /hijack/{id}/acquire, POST /hijack/{id}/send, POST /hijack/{id}/release, GET /hijack/{id}/snapshot.
• WebSocket proxy — three WS endpoints per session:
  • /ws/worker/{worker_id}/term — runtime worker protocol (JSON frames)
  • /ws/browser/{worker_id}/term — browser/operator protocol (JSON frames)
  • /ws/raw/{worker_id}/term — raw stream mode for uterm listen telnet/SSH gateways
• Hibernation-safe — uses CF WebSocket Hibernation API; state survives DO sleep/wake cycles.
• WS session resumption — browser reconnects reclaim their role and hijack ownership via one-time tokens stored in DO SQLite; see docs/cf-do-architecture.md.
• Quick-connect — POST /api/connect creates sessions in KV; SPA serves the connect form at /app/connect. Supports shell, websocket, and ushell connector types.

Auth modes

Set AUTH_MODE in wrangler.toml or .dev.vars. jwt is the only supported value — the worker is always internet-facing, so any other mode (dev/none are removed) raises a ValueError at config load.

WORKER_BEARER_TOKEN is also required and must clear a 32-character / non-placeholder entropy floor.

Current gaps

• The quick-connect form creates sessions in KV but the CF worker cannot run shell/SSH/telnet connectors itself — a worker process must bridge in via WS.
• The hijack REST surface is intended to match the FastAPI contract, but there are still backend-parity gaps; treat docs/protocol-matrix.md as the target contract, not a guarantee that every edge case is identical today.

Commands

uv run pywrangler dev        # local dev server (sync deps + wrangler dev)
uv run pywrangler deploy     # deploy to Cloudflare
uterm-cf build               # build only
uterm-cf deploy --env production

Docker alternative

# Build and run from repo root
docker build -f docker/Dockerfile.cf -t provide-uterm-cf .
docker run --rm -p 27788:27788 provide-uterm-cf

# JWT auth test
docker run --rm -p 27788:27788 \
  -e AUTH_MODE=jwt \
  -e JWT_JWKS_URL=https://<team>.cloudflareaccess.com/cdn-cgi/access/certs \
  -e JWT_ISSUER=https://<team>.cloudflareaccess.com \
  -e JWT_AUDIENCE=<aud-tag> \
  provide-uterm-cf

Tests

Unit tests (no network required):

uv run pytest tests/ -v

E2E tests against a local wrangler dev instance or the live worker:

E2E=1 uv run pytest -m e2e -v
REAL_CF=1 REAL_CF_URL=https://provide-uterm-cloudflare.neurotic.workers.dev uv run pytest -m e2e -v

Related

• Main package: provide-uterm
• Terraform for KV provisioning: terraform/