CLI & Control Plane

The stem CLI complements the programmatic APIs—use it to inspect state, manage workers, and operate schedules and routing.

Inspect vs control

• Inspect commands read state (stem observe ..., stem worker stats) and are safe to run frequently.
• Control commands mutate worker state (stem worker revoke, stem worker shutdown) and should be restricted to operators.
• Broadcast commands (like stem worker ping) fan out to all workers unless you target a specific worker ID.
• Use --namespace to ensure the CLI targets the same namespace as your workers.

Remote control primer

The worker control commands (ping, stats, inspect, revoke, shutdown, pause, resume) publish control messages into the broker. Each command uses a request id and waits for replies on a per-request reply queue.

Targeting rules:

• Broadcast (default): omit --worker to broadcast to every worker in the namespace.
• Targeted: pass one or more --worker values to address specific worker ids only.

Inspect vs control semantics:

• Inspect (ping, stats, inspect) returns snapshots and does not mutate worker state.
• Control (revoke, shutdown, pause, resume) persists intent and asks workers to change behavior (terminate tasks, shut down, or pause queue consumption).

Payload highlights (as sent by the CLI):

• ping/stats: command type with a targets list (defaults to *).
• inspect: includes includeRevoked and the control namespace.
• revoke: includes revocations plus requester and namespace.
• shutdown: includes mode (warm, soft, hard).

Example usage:

# Broadcast to all workers
stem worker ping

# Target a single worker by id
stem worker stats --worker worker-a

Observe queues

const String observeQueuesCommand = 'stem observe queues';

Observe workers

const String observeWorkersCommand = 'stem observe workers';

Observe DLQ

const String observeDlqCommand = 'stem observe dlq';

Observe schedules

const String observeSchedulesCommand = 'stem observe schedules';

Ping workers

const String workerPingCommand = 'stem worker ping';

Worker stats

const String workerStatsCommand = 'stem worker stats';

Revoke a task

const String workerRevokeCommand = 'stem worker revoke --task <id>';

Shutdown workers

const String workerShutdownCommand = 'stem worker shutdown --mode warm';

Pause queues

const String workerPauseCommand = 'stem worker pause --queue default';

Resume queues

const String workerResumeCommand = 'stem worker resume --queue default';

Apply schedules

const String scheduleApplyCommand =
    'stem schedule apply --file config/schedules.yaml --yes';

List schedules

const String scheduleListCommand = 'stem schedule list';

Dry-run a schedule

const String scheduleDryRunCommand = 'stem schedule dry-run --spec "every:5m"';

Registry resolution

Many CLI commands that reference task names need a registry. The default CLI context does not load one automatically, so wire it via runStemCli with a contextBuilder that sets CliContext.registry. For multi-binary deployments, ensure the CLI and workers share the same registry entrypoint so task names, encoders, and routing rules stay consistent.

If a command needs a registry and none is available, it will exit with an error or fall back to raw task metadata (depending on the subcommand).

List registered tasks

stem tasks ls

Expected output:

NAME            DESCRIPTION        IDEMPOTENT  TAGS
email.send      Sends an email     yes         notifications

Observe queues, workers, and schedules

stem observe queues
stem observe workers
stem observe dlq
stem observe schedules

Expected output:

Queue     | Pending | Inflight
Worker    | Active  | Last Heartbeat
Queue     | Task ID                        | Reason
Summary: due=... overdue=...

Requirements:

• stem observe queues and stem observe dlq need a broker.
• stem observe workers requires a result backend.
• stem observe schedules reads from STEM_SCHEDULE_STORE_URL or a schedule file.

Worker control commands

stem worker ping
stem worker stats
stem worker revoke --task <id>
stem worker shutdown --mode warm
stem worker pause --queue default
stem worker resume --queue default

Expected output:

ping: ok
stats: workers=... queues=...

Combine with programmatic signals for richer telemetry (see Worker Control CLI).

Scheduler

stem schedule apply \
  --file config/schedules.yaml \
  --yes

stem schedule list
stem schedule dry-run --spec "every:5m"

Run Beat from a Dart entrypoint wired to your schedule store:

lib/scheduler.dart

Future<void> startRedisBeat() async {
  final brokerUrl =
      Platform.environment['STEM_BROKER_URL'] ?? 'redis://localhost:6379';
  final store = await RedisScheduleStore.connect('$brokerUrl/2');
  final beat = Beat(
    broker: await RedisStreamsBroker.connect(brokerUrl),
    store: store,
    lockStore: await RedisLockStore.connect('$brokerUrl/3'),
  );

  await applyScheduleFile(store, 'config/schedules.yaml');
  await beat.start();
}

class EmailTask extends TaskHandler<void> {
  @override
  String get name => 'email.send';

  @override
  TaskOptions get options => const TaskOptions(queue: 'default');

  @override
  Future<void> call(TaskContext context, Map<String, Object?> args) async {}
}

Requirements:

• stem schedule apply/list/dry-run use STEM_SCHEDULE_STORE_URL when set, otherwise they operate on local schedule files.
• Beat needs a broker, schedule store, and (for HA) a lock store.

Expected output (schedule list):

ID        | Task           | Queue    | Spec             | Next Run                | Last Run                | Jitter  | Enabled
----------+----------------+----------+------------------+------------------------+------------------------+---------+---------
cleanup   | maintenance... | default  | every:5m         | 2025-01-01T00:05:00Z    | 2025-01-01T00:00:00Z    | 0ms     | yes

Health checks

stem health \
  --broker "$STEM_BROKER_URL" \
  --backend "$STEM_RESULT_BACKEND_URL"

The command exits non-zero when connectivity, TLS, or signing checks fail—ideal for CI/CD gates.

Backend requirements by command

Use this table to sanity-check which connection strings are required:

Command	Broker	Result backend	Schedule store	Revoke store	Registry
stem tasks ls	❌	❌	❌	❌	✅
stem observe queues	✅	❌	❌	❌	❌
stem observe workers	❌	✅	❌	❌	❌
stem observe dlq	✅	❌	❌	❌	❌
stem observe schedules	❌	❌	✅	❌	❌
stem worker ping/stats/inspect	✅	❌	❌	❌	❌
stem worker status	optional (follow)	optional (snapshot)	❌	❌	❌
stem worker revoke	✅	optional	❌	optional	❌
stem worker shutdown	✅	❌	❌	❌	❌
stem worker pause/resume	✅	❌	❌	optional	❌
stem schedule apply/list/dry-run	❌	❌	✅	❌	❌
stem health	✅	optional	❌	❌	❌

Notes:

• The CLI resolves URLs from STEM_BROKER_URL, STEM_RESULT_BACKEND_URL, STEM_SCHEDULE_STORE_URL, and STEM_REVOKE_STORE_URL.
• STEM_REVOKE_STORE_URL supports redis://, postgres://, sqlite:///, file:///, and memory:// targets.
• When a backend is “optional”, the command still runs but will skip that slice of data (for example, worker heartbeats without a result backend).
• Schedule commands fall back to local schedule files when no schedule store is configured.

Keep the CLI handy when iterating on the code examples in the feature guides.