Logging

Miravo uses consola with tagged loggers for each subsystem.

Log Levels

Level	Flag	Description
debug	--verbose	Generator evaluations, tick details, adapter internals
info	Default	Startup, shutdown, periodic summaries, state transitions
warn	—	Overrun warnings, adapter saturation, deprecation notices
error	—	Tick failures, adapter errors, command failures

Set the level:

miravo start --log-level debug
miravo start --verbose          # Same as --log-level debug
miravo start -q                 # Quiet: suppress non-error output

Priority: -q/--quiet > --log-level > --verbose.

Output Formats

Pretty (default)

Human-readable colored output with tagged prefixes:

[engine] Simulation "smart-factory" started (7 instances, 1 template)
[mqtt]   Embedded broker listening on 127.0.0.1:1883
[engine] Tick 30 | 7 instances · 168 values | MQTT: 168 pub · 0 err

JSON

Structured JSON, one object per line. Ideal for log aggregation (ELK, Datadog, Loki):

miravo start --log-format json

{"ts":"2026-03-18T10:00:00.000Z","level":"info","tag":"engine","simulationName":"smart-factory","runId":"abc123","message":"Simulation started"}

JSON fields: ts, level, tag, simulationName, runId, message.

Plain

No colors or formatting. Useful for CI/CD or piping:

miravo start --plain

Or via environment variable:

NO_COLOR=1 miravo start

Logger Tags

Each subsystem has a tagged logger:

Tag	Subsystem
engine	Core engine, scheduler, lifecycle
mqtt	MQTT adapter, broker, control transport
opcua	OPC UA adapter, server, address space
admin	Admin HTTP server
cli	CLI command processing

Periodic Summary

Every 30 seconds (configurable with --summary-interval), Miravo logs a summary line:

Tick 1800 | 7 instances · 168 values | MQTT: 302,400 pub · 0 err | OPC UA: disabled

This includes tick count, instance count, member value count, and per-adapter statistics.

Streaming Events

Use miravo logs to stream domain events from a running background simulation:

Stream all events:

miravo logs my-sim

Last 50 events, then stream:

miravo logs my-sim --tail 50

Filter by channel:

miravo logs my-sim --channels faults,lifecycle

Available channels: tick, faults, lifecycle, instances, engine, adapters.