Configuration

All configuration is environment variables. There is no config file and no runtime configuration API.

Server

Variable	Required	Default	Description
REDIS_URL	yes	—	Redis connection string, e.g. redis://localhost:6379 or rediss://user:pass@host:port. Only pub/sub is used. The process throws on startup if this is missing.
PORT	no	3077	TCP port to listen on. Deno Deploy sets this for you.
APP_FQDN	no	http://localhost:$PORT	Host used to build the URL encoded in the QR code on channel pages. Routing does not use it.

Locally these come from a .env file in the project root, loaded automatically by just:

# .env — gitignored, because REDIS_URL usually carries a password
REDIS_URL=redis://localhost:6379
APP_FQDN=localhost:3077
PORT=3077

In production they are set on the Deno Deploy application, not baked into a deploy:

just env-list    # what production is using
just env-push    # push ./.env into the application

Tests

Variable	Default	Description
REDIS_URL	redis://localhost:6379	Redis the test cluster publishes through.
TEST_BASE_PORT	3100	First port of the test cluster; instances use PORT, PORT+1, PORT+2.
TEST_SERVER_LOGS	unset	Set to 1 to stream the test servers' stdout and stderr, prefixed by instance.

Deployment

The Deno Deploy target lives in the deploy block of deno.json rather than in the dashboard, because that block takes precedence over dashboard settings:

{
  "deploy": {
    "org": "metapage",
    "app": "websocket-router",
    "runtime": {
      "mode": "dynamic",
      "entrypoint": "src/serve.ts"
    }
  }
}

Authentication for deno deploy uses the device login from deno deploy login.

DENO_DEPLOY_TOKEN will break your deploys

Deploy Classic ddp_ tokens are not valid for deno deploy. If one is exported in your shell it overrides the device login and every deploy fails with AUTH_INVALID_TOKEN. Unset it.

Constants

Not configurable, but worth knowing. All live in src/handlerWs.ts.

Constant	Value	Meaning
MINIMUM_CHANNEL_NAME_LENGTH	6	Shorter names are rejected with close code 1008
PING_PREFIX	"ping"	Messages starting with this are keepalives and are not routed
PONG_MESSAGE	"client ping: pong from server"	Reply sent to the pinging client
SERVER_INSTANCE_ID_LENGTH	6	Length of the per-process id prefixed to redis publications