Logs

Stewart writes its log to standard output: make logs follows it, and make run shows it in the foreground. A line looks like this:

2026-10-21 14:03:12.345+02:00 INFO [porch-light] Turning on {"entity":"light.porch","worker":0}

Part	What it says
2026-10-21 14:03:12.345+02:00	When, with the offset of Stewart’s time zone
INFO	The level: DEBUG, INFO, NOTICE, WARNING, ERROR or worse
[porch-light]	What the line is about (see below)
Turning on	The message
{…}	The details; worker is the worker the app runs on

The tag in brackets is one of:

Tag	Lines
An app ID, such as [porch-light]	What the app logs through its LoggerInterface, and what Stewart logs about it, such as App failed or App paused
[@shared]	Stewart’s own code inside a worker, outside any app
[broker]	The daemon itself: the connection to Home Assistant, workers, reloads
[worker 0]	Text a worker printed outside the logger, such as a PHP fatal error or a var_dump()

So make logs | grep '\[porch-light\]' shows everything about one app.

JSON

For a log collector such as Loki or Elasticsearch, log_format: json (or STEWART_LOG_FORMAT=json, or stewart run --json-logs) writes one JSON object per line. extra.source holds the tag, and context.app and context.worker name the app and its worker:

{"message":"Turning on","context":{"entity":"light.porch","app":"porch-light","worker":0},"level":200,"level_name":"INFO","channel":"stewart","datetime":"2026-10-21T14:03:12.345678+02:00","extra":{"source":"porch-light"}}

One app’s log level

log_level sets how much Stewart says: debug, info (the default), notice, warning or error. One app can say more or less than that:

log_level: info
apps:
  porch-light:
    log_level: debug     # its debug lines too
  energy-report:
    log_level: warning   # only its warnings and errors

From the environment, that is STEWART_APPS__PORCH_LIGHT__LOG_LEVEL=debug.

An app’s level covers what the app logs and what Stewart logs about it; [broker] and [@shared] lines keep the global log_level. A reload (make reload) applies a changed app level. The global log_level, like --log-level, takes effect at the next restart.

Tracing an app

When an app does not react, or reacts when it should not, trace it. A traced app logs what reaches it and what it does with it, labelled TRACE, whatever log_level says:

make run TRACE=porch-light     # also make watch and make debug; TRACE="porch-light hall" for two

stewart run --trace=porch-light does the same; repeat it for more apps. To keep an app traced, set it in stewart.yaml, and a reload applies it:

apps:
  porch-light:
    trace: true

A trace reads like this:

… TRACE [porch-light] Event received {"subscription":"state_change exact:binary_sensor.porch_motion","id":"w0:3","change":"on → off"}
… TRACE [porch-light] Event received {"subscription":"state_change exact:binary_sensor.porch_motion","id":"w0:3","change":"off → on"}
… TRACE [porch-light] Handler called {"subscription":"state_change exact:binary_sensor.porch_motion","id":"w0:3"}
… TRACE [porch-light] Action call sent {"action":"light.turn_on","target":{"entity_id":["light.porch"]}}
… TRACE [porch-light] Action call answered {"action":"light.turn_on","outcome":"succeeded","took":"42ms"}

Line	Means
Event received	A state change, event, topic, MQTT message or trigger reached one of the app’s subscriptions, before its operators
Handler called	The event got through the operators (filter(), whenChangedTo(), debounce(), …) and the app’s handler ran
Event skipped while paused	The app is paused, so the event went nowhere
Schedule ran, Schedule run skipped while paused	A schedule or a timer came due
Action call sent, Action call answered	A call to Home Assistant, how it went and how long it took

An Event received with no Handler called after it means an operator stopped the event: a filter() said no, or whenChangedTo('on') saw a change from unavailable. A debounce() or whenStableFor() calls the handler later, so its Handler called comes on its own. No Event received at all means nothing matched: check the entity ID, and that the app runs (make status). id tells two subscriptions to the same entity apart.

In JSON, a trace record keeps the debug level (100) and has level_name TRACE. Trace one app rather than setting log_level: debug: debug adds Stewart’s own lines for every app.