Struct JanusSupervisor 

pub struct JanusSupervisor { /* private fields */ }

The central supervisor for the Janus system.

Manages the lifecycle of all JanusService implementations using TaskTracker for structured concurrency and CancellationToken for graceful shutdown propagation.

Memory Safety

Unlike JoinSet, TaskTracker does not accumulate task return values. Completed task memory is reclaimed immediately, making this safe for long-running processes that may restart services hundreds of times over weeks of operation.

Implementations

impl JanusSupervisor

pub fn new(config: SupervisorConfig) -> Self

Create a new supervisor with the given configuration.

pub fn with_defaults() -> Self

Create a new supervisor with default configuration.

pub fn cancel_token(&self) -> &CancellationToken

Get a reference to the supervisor’s cancellation token.

Useful for external code that needs to observe or trigger shutdown.

pub fn metrics(&self) -> &Arc<SupervisorMetrics>

Get a reference to the supervisor’s metrics.

pub async fn lifecycle_snapshots(&self) -> Vec<ServiceLifecycleSnapshot>

Get a snapshot of all service lifecycles.

pub async fn service_lifecycle( &self, name: &str, ) -> Option<ServiceLifecycleSnapshot>

Get the lifecycle snapshot for a specific service by name.

pub async fn service_count(&self) -> usize

Number of services currently tracked (alive + terminated).

pub fn trigger_shutdown(&self)

Trigger a graceful shutdown of all managed services.

This cancels the root cancellation token, which propagates to all child tokens held by running services. The supervisor’s run_until_shutdown (or wait_for_drain) will then wait for tasks to complete up to the configured timeout.

pub fn is_shutting_down(&self) -> bool

Returns true if the supervisor’s shutdown has been triggered.

pub fn spawn_service(&self, service: Box<dyn JanusService>)

Spawn a service into the supervisor with default options.

The service will be wrapped in a restart loop governed by its RestartPolicy and the supervisor’s default BackoffConfig.

pub fn spawn_service_with_options( &self, service: Box<dyn JanusService>, options: SpawnOptions, )

Spawn a service with custom per-service options.

pub async fn wait_for_drain(&self)

Close the tracker and wait for all tasks to complete, with timeout.

Call this after triggering shutdown (or after run_until_shutdown returns) to ensure all tasks have drained.

pub async fn run_until_shutdown(&self) -> Result<()>

Run the supervisor until a shutdown signal is received.

If install_signal_handler is true in the config (the default), this will listen for Ctrl+C / SIGTERM and trigger shutdown.

Returns after all services have drained (or the shutdown timeout has elapsed).