collabSupport/dect-relay-agent
Joseph McQueen 4f9ebdb5fb Rework DECT relay bundle to ship a pre-built Docker image
The previous packager (scripts/packageDectRelayAgent.js) shipped a
source-only bundle and expected the DC host to build the image with
`docker compose up --build`. That fails hard in corporate DCs with
TLS-intercepted egress: Alpine's apk fetch of dl-cdn.alpinelinux.org
can't verify the intercepted certificate ("apk: TLS: server
certificate not trusted"), and npm install would fail the same way
if apk had succeeded.

New approach: build the image ONCE on the dev machine (where TLS
works), save it as a gzipped tarball, and ship a ZIP whose install
step is `docker load` + `docker compose up -d`. Zero network calls
inside the DC container, ever.

Bundling (dev-machine):
- dect-relay-agent/bundle.sh: build → docker save → gzip → zip.
  Auto-derives version from package.json, records git sha + dirty
  flag + build date into image labels. Cross-arch friendly
  (--platform=linux/amd64 by default; --platform linux/arm64 for
  ARM DCs). Output: dect-relay-agent-bundle-<YYYYMMDD-HHMMSS>.zip
  at repo root (typically 40-60MB).
- dect-relay-agent/Dockerfile: multi-stage node:20-alpine build.
  No apk add. No runtime npm install. Non-root `node` user (uid
  1000). Node handles SIGTERM natively via index.js handlers, so
  no tini/dumb-init needed. Designed to build from the REPO ROOT
  (not the agent folder) because the agent imports shared modules
  from ../integrations/cisco-dect and ../utils.
- dect-relay-agent/Dockerfile.dockerignore: per-Dockerfile ignore
  (BuildKit ≥ 23.0) with a whitelist that keeps the build context
  to ~50KB. Older Docker daemons fall through to the repo-root
  .dockerignore, which already excludes secrets — nothing sensitive
  can leak either way.
- package.json: `npm run package:relay` now invokes bundle.sh.

Runtime (DC-host):
- dect-relay-agent/docker-compose.yml: pins IMAGE_TAG from .env
  (install.sh writes it there — never falls back to :latest), reads
  the rest of the config via env_file, restart: unless-stopped,
  host networking (needed to reach 10.x/8 without userland proxy
  translation, and the agent doesn't listen on anything). Hardened:
  read_only: true rootfs with a 16MB /tmp tmpfs, cap_drop: ALL,
  no-new-privileges, log rotation at 10MB × 5 files.
- dect-relay-agent/install.sh: preflight (docker + compose present,
  daemon reachable, bundle files intact), docker load, pin loaded
  tag into .env, validate .env has the three required values not
  still set to placeholder strings, docker compose up -d, tail last
  40 log lines. Idempotent — safe to re-run on upgrades.

Cleanup:
- scripts/packageDectRelayAgent.js: deleted (superseded).
- .gitignore: drops the scripts/* + !packageDectRelayAgent.js dance
  since we no longer need to whitelist that one file; add pattern
  for the datestamped bundle zips + staging dirs at repo root.
- dect-relay-agent/README.md: replaces the deploy section with the
  new dev-machine-build → DC-host-load workflow, plus a
  troubleshooting section keyed on the exact error messages seen
  during the failed in-DC build (TLS cert not trusted, docker perm
  denied, DIGEST_401).

Verified: all 113 existing tests still pass. Docker build itself
requires a Docker daemon (dev machine) so can't be exercised in
this sandbox — the bash scripts pass `bash -n` syntax checks.
2026-07-03 10:05:05 -04:00
..
.env.example DECT relay Phase 1: WSS hub + agent + /phonestatus follow-up 2026-07-02 17:03:32 -04:00
bundle.sh Rework DECT relay bundle to ship a pre-built Docker image 2026-07-03 10:05:05 -04:00
docker-compose.yml Rework DECT relay bundle to ship a pre-built Docker image 2026-07-03 10:05:05 -04:00
Dockerfile Rework DECT relay bundle to ship a pre-built Docker image 2026-07-03 10:05:05 -04:00
Dockerfile.dockerignore Rework DECT relay bundle to ship a pre-built Docker image 2026-07-03 10:05:05 -04:00
index.js DECT relay Phase 1: WSS hub + agent + /phonestatus follow-up 2026-07-02 17:03:32 -04:00
install.sh Rework DECT relay bundle to ship a pre-built Docker image 2026-07-03 10:05:05 -04:00
package.json DECT relay Phase 1: WSS hub + agent + /phonestatus follow-up 2026-07-02 17:03:32 -04:00
README.md Rework DECT relay bundle to ship a pre-built Docker image 2026-07-03 10:05:05 -04:00

DECT Relay Agent

Bridges the CollabSupport bot (public cloud) to Cisco DBS-210 DECT base stations on the private 10.0.0.0/8 corporate network.

Why it exists

The bot process runs in the public cloud and can't reach 10.x. This agent runs inside the data center, dials outbound over WSS to the bot, and executes any DECT command (collect status, reboot, factory-reset, etc.) the bot pushes to it.

Only one agent is expected to run at a time. If a second agent connects, the bot assumes it's a legitimate restart, closes the old socket, and adopts the new one.

Prerequisites

  • Node.js ≥ 20
  • Route from the agent host to 10.0.0.0/8 on TCP 443
  • Route from the agent host to the bot's public HTTPS endpoint
  • The DECT serviceability password (Control Hub → Calling → Features → DECT Networks → Manage → Manage DECT serviceability password)

Deploy paths

There are two ways to run this. Pick one based on where you're deploying.

The DC host makes zero network calls during install — the image is built on your dev machine, saved as a tarball, and shipped inside a self-contained ZIP. This sidesteps the TLS-interception problem that breaks apk add and npm install inside containers on corporate networks.

On your dev machine (with Docker Desktop / internet access):

# From the repo root — script is self-locating:
./dect-relay-agent/bundle.sh
# → writes dect-relay-agent-bundle-<YYYYMMDD-HHMMSS>.zip (~40-60MB)

Optional overrides:

./dect-relay-agent/bundle.sh --tag 0.2.0            # override version
./dect-relay-agent/bundle.sh --platform linux/arm64 # if the DC is ARM

On the DC host (once you've transferred the ZIP):

unzip dect-relay-agent-bundle-*.zip
cd dect-relay-agent-bundle-*
cp .env.example .env
$EDITOR .env                      # set BOT_URL + AGENT_TOKEN + ADMIN_PASSWORD
./install.sh

install.sh is idempotent — re-run it after transferring a newer bundle to upgrade. It:

  1. docker loads the image tarball
  2. Pins the loaded tag into .env (so compose never falls back to a stale local image)
  3. Validates required env values are set (not still placeholder strings)
  4. docker compose up -d
  5. Tails the last 40 log lines so you can see the "Connected — sending hello" message

What the runtime container looks like:

  • Non-root node user (uid 1000)
  • Read-only root filesystem, 16MB tmpfs at /tmp
  • All Linux capabilities dropped, no-new-privileges
  • Host networking (so it can reach 10.x/8 without userland proxy translation)
  • No listening ports — outbound-only WSS to the bot
  • Log rotation: 10MB × 5 files max

2. Direct node process (dev + local iteration)

cd dect-relay-agent
npm install

ws, axios, and dotenv are the only runtime dependencies. The agent imports the shared integrations/cisco-dect/ modules from the parent repo via relative paths, so the parent workspace must be present on disk.

Configure

cp .env.example .env
$EDITOR .env

Required values:

Var Meaning
DECT_RELAY_BOT_URL Full WSS URL to the bot's DECT relay endpoint (wss://your-bot-host/dect-relay/ws)
DECT_RELAY_AGENT_TOKEN Shared bearer token — MUST match the bot's DECT_RELAY_AGENT_TOKEN exactly
DECT_ADMIN_USER Usually admin
DECT_ADMIN_PASSWORD Fleet-wide serviceability password

Generate a fresh token: openssl rand -hex 32. Rotate on both sides at once — the bot compares tokens with timingSafeEqual and will reject any drift with a 401 on the WSS upgrade.

Run

npm start

You should see:

[startup] dect-relay-agent v0.1.0 — hostname=..., bot=wss://...
[connect] Dialing wss://.../dect-relay/ws
[connect] Connected — sending hello

And on the bot side:

[dect:relay-hub] Agent connected from ...
[dect:relay-hub] Agent hello: version=0.1.0 host=... caps=collect,reboot,...

Wire protocol

All frames are JSON, one per WebSocket message.

Agent → Bot on connect:

{ "type": "hello",
  "agentVersion": "0.1.0",
  "hostname": "dc-dect-relay-01",
  "capabilities": ["collect","reboot","force-reboot","reboot-chain",
                   "force-reboot-chain","factory-reset","reconfigure-tree"] }

Bot → Agent (command):

{ "id": "cmd_<uuid>", "type": "collect", "baseIp": "10.4.11.87" }
{ "id": "cmd_<uuid>", "type": "reboot",  "baseIp": "10.4.11.87" }

Agent → Bot (reply):

{ "id": "cmd_<uuid>", "ok": true, "elapsedMs": 812,
  "result": { "parsed": { ... }, "verdict": { "healthy": true, ... } } }

{ "id": "cmd_<uuid>", "ok": false,
  "error": { "code": "DIGEST_401", "message": "Base rejected credentials" } }

Heartbeat (both directions, every 30s):

{ "type": "ping", "at": 1720000000000 }
{ "type": "pong", "at": 1720000000000 }

The bot terminates the socket if no pong arrives within 90s; the agent auto-reconnects with exponential backoff (1s / 2s / 4s / … capped at 30s + 0-1000ms jitter).

Safety guarantees

  • DECT admin credentials NEVER leave this agent. The bot only knows the WSS bearer token.
  • All mutating actions (reboot, factory-reset, reconfigure-tree) are only executed when the bot explicitly issues the corresponding command frame. The agent has no autonomous logic.
  • The agent enforces no policy — the bot decides who can reboot what. See the bot's audit log for the full record of actions taken (igmp:audit style scopes in daily log files).
  • The agent quarantines mutating actions from probes via the exact same safety model as the CLI tool (integrations/cisco-dect/probes.js — GET-triggered actions are only reachable via explicit trigger* helpers, never via a generic path fetcher).

What's in this folder

File Purpose
index.js Agent entrypoint — WSS client + command dispatcher
package.json Deps: ws, axios, dotenv
.env.example Annotated env template
README.md This file
Dockerfile Multi-stage Alpine build. No apk add, no runtime npm install.
Dockerfile.dockerignore Per-Dockerfile ignore (BuildKit ≥ 23.0). Whitelist-based; keeps build context ~50KB.
docker-compose.yml DC-side runtime shape (read-only rootfs, host net, capability drop, log rotation).
bundle.sh Dev-machine packager: docker builddocker savezip. Runs on your machine.
install.sh DC-host installer: docker load → validate .envdocker compose up -d. Ships inside the bundle.

Important: the Dockerfile is designed to be built from the repo root, not from this folder, because it needs ../integrations/cisco-dect/* and ../utils/httpDigestAuth.js in the build context. bundle.sh does this correctly:

docker build -f dect-relay-agent/Dockerfile -t ... .   # note the trailing `.`

Building with docker build dect-relay-agent/ will fail (missing shared modules) — always use bundle.sh, or invoke docker build from the repo root with -f dect-relay-agent/Dockerfile.

Troubleshooting

WARNING: fetching … TLS: server certificate not trusted during build You're building inside a TLS-intercepting corporate network. Don't — build on your dev machine and ship the tarball via bundle.sh. That's the whole point of this workflow.

docker: permission denied while trying to connect to the Docker daemon socket The user running install.sh needs to be in the docker group. Either sudo usermod -aG docker $USER (log out/in after) or sudo ./install.sh.

Agent connects then immediately disconnects with 401 Bearer token mismatch. DECT_RELAY_AGENT_TOKEN on the bot side must match the agent's .env exactly. Rotate both together.

Agent connects but every collect returns DIGEST_401 DBS-210 admin password is wrong. Verify in Control Hub → Calling → Features → DECT Networks → Manage → Manage DECT serviceability password, update DECT_ADMIN_PASSWORD in .env, then docker compose restart dect-relay-agent.