Functions

Trust boundary

Function code is admin-trusted — equivalent to deploying code to the server. It runs in the same Node.js process with full grpcSdk privileges. The VM layer applies a per-invocation timeout and limits require to lodash and axios only. These are guardrails against accidents, not a security boundary for malicious code. Do not use this module for tenant-submitted scripts.

For user-facing filtered queries, use database custom endpoints at /database/function/{name} on the Client API instead.

Handler shape

Stored functionCode is the body of:

function (grpcSdk, req, res) {
  // your code
}

Parameter	Meaning
grpcSdk	Conduit gRPC SDK — database, auth, storage, chat, communications, …
req	Parsed request: HTTP params/body/query for routes; event payload for bus/cron
res	Callback (data) => void — return value mapped through returns schema

console.log output is captured in execution logs.

Function types

functionType	Trigger	Client API surface
request	HTTP route	/{name} (+ optional /:urlParams)
webhook	HTTP route (no auth middleware by default)	/hook/{name}
middleware	Global middleware	Registered as named middleware on /
socket	Socket.io event	Namespace path /{name}, event from inputs.event
event	Redis bus subscription	inputs.event = bus channel name
cron	BullMQ repeatable job	inputs.event = cron expression

The module waits for router to be serving before registering routes (watch: router rising).

HTTP methods and PUT mapping

inputs.method accepts GET, POST, PUT, PATCH, or DELETE. PUT maps to ConduitRouteActions.UPDATE — the same route action Hermes uses for update verbs (not GET). This matters when declaring returns and when matching routes in middleware patches.

Optional inputs.auth: true on request functions adds authMiddleware.

Declare inputs.bodyParams, inputs.queryParams, and inputs.urlParams to validate incoming data; urlParams append /:key segments to the route path.

VM sandbox

Each invocation runs inside node:vm:

• Timeout — per-function timeout in milliseconds (default 180000 / 3 minutes)
• require allowlist — only lodash (lodash-es) and axios; anything else throws at runtime
• Single run — compile + invoke share one timeout budget

Syntax is validated on upload (POST /functions/upload) and update (PATCH /functions/:id).

Event functions

functionType: event subscribes to grpcSdk.bus on channel inputs.event. Payloads are passed as req (JSON-parsed when the bus message is a JSON string). Handler errors are logged; they do not block the publisher.

Cron functions (BullMQ)

functionType: cron stores a cron expression in inputs.event (for example 0 */6 * * *). The functions module registers a BullMQ repeatable job on Redis — the same job-queue infrastructure used by database and communications modules. On each tick the handler runs with an empty or minimal req payload.

Cron requires the platform Redis connection used by other BullMQ workers (grpcSdk.redisManager) — there is no separate FUNCTIONS_REDIS_* configuration. Execution history is recorded like other function types.

Returns mapping

If returns is omitted, the handler result is wrapped as { result: data }. When returns is a schema object, only declared keys are forwarded from the res(...) payload. Set returns: "String" for a plain string result.

When to use Functions vs alternatives

Need	Use
Filtered Client API query	Database custom endpoint
Long-running domain service	Custom ManagedModule
Webhook, cron, bus automation	Functions
System chat message from backend	grpcSdk.chat from Function or custom module