Rind

Signals

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Signals in Rind are typed event definitions emitted into the Flow runtime. A signal does not persist in the State Machine; it is emitted, validated against its payload type, and used to trigger dependent transitions.

Core Definition

The base signal metadata defines identity and payload type.

  • name: The unique signal name.
  • payload: Payload type. Valid values are json, string, bytes, none.
[[signal]]
name = "activate"
payload = "string"
[[signal]]
name = "request_login"
payload = "json"

Dependent Signal Chains

Signals can trigger other signals via after.

  • after: List of FlowItem conditions that must match.
  • Runtime emits dependent signal only when all after conditions are active/matching.
  • This is evaluated in reconcile_signal_transcendence after emit_signal.
[[signal]]
name = "request_logout"
payload = "json"
after = ["sessions@request_login"]

FlowItem Matching (after Details)

after accepts simple or detailed condition entries.

  • Simple: "name"
  • Detailed:
  • { state = "..." } or { signal = "..." }
  • Optional target / branch operations:
  • String equality, or
  • option object: { binary = true }, { contains = "..." }, { as = { ... } }
[[signal]]
name = "notify-admin"
payload = "json"
after = [
  { state = "backup-result", target = { as = { status = "failed" } } }
]

Transport Subscribers

Signals can publish set/remove events to configured Transport subscribers.

  • subscribers: Defined on signal metadata and parsed from TOML.
  • Current flow runtime does not publish signal events through this field.
  • Signal transport publication currently occurs through event/transport runtime paths, not Signal.subscribers.

Permission Gates

Signal emission through incoming transport can be permission-gated.

  • permissions: List of permission IDs (either u16 or full name to Permissions).
  • Checked in transport incoming handling before flow.emit_signal dispatch.
[[signal]]
name = "deactivate"
payload = "string"
permissions = [2001, "myperm"]

Broadcast

  • broadcast: Defined on the model and accepted in TOML.
  • Current flow runtime path does not consume this field yet.

Service Integration

Services emit signals through lifecycle hooks, and flow consumes them immediately.

[[service]]
name = "backup-job"
run.exec = "/usr/bin/backup"
on-stop = [{ signal = "backup@complete", payload = { status = "success" } }]

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