Observability

Every queue event the framework emits targets nest_rs::queue. One target, every worker-side log filterable by RUST_LOG=nest_rs::queue=debug, one span wrapping each job so its events share the same fields. The service-level logs your #[process] method emits keep their own target (e.g. features::audio) — same convention as the rest of the framework.

Targets and levels

Target	What	Level
nest_rs::queue	Boot registration, per-job span + events, skipped/unversioned warnings.	debug on job start, info on success, warn on failure.
nest_rs::transport	Boot: attached module-contributed transport transport=QueueWorker.	info.
features::<feature>	Your service-level logs inside the #[process] method.	Your call.

Hot paths respect RUST_LOG=info: job started sits at debug, so a worker at info logs one job ok line per successful ack and a job failed line per failed attempt — nothing per-poll noise.

The per-job span

The worker opens one span per job attempt, target nest_rs::queue, name process job. The handler runs inside it, so any tracing event your service emits — and the framework’s own start/end events — are tagged with the span’s fields:

Field	Notes
queue	The Redis queue name.
processor	The processor host name, e.g. AudioProcessor::transcode.
job_id	The apalis TaskId for this job.
attempt	The apalis attempt counter (1 on the first try, higher on retries).

attempt distinguishes retries of the same job_id. The OTLP appender from nest-rs-opentelemetry exports these as span attributes.

What a job’s life looks like

On success the worker emits job started at debug and job ok at info (carrying elapsed_ms, the wall time of the handler call):

DEBUG process job{queue=audio processor=AudioProcessor::transcode job_id=01HFEX… attempt=1}: nest_rs::queue: job started
 INFO process job{queue=audio processor=AudioProcessor::transcode job_id=01HFEX… attempt=1}: features::audio: transcoded file=track-1717405126521.mp3
 INFO process job{queue=audio processor=AudioProcessor::transcode job_id=01HFEX… attempt=1}: nest_rs::queue: job ok elapsed_ms=342

A failed attempt emits job failed at warn, carrying elapsed_ms and the error:

DEBUG process job{queue=audio processor=AudioProcessor::transcode job_id=01HFFA… attempt=1}: nest_rs::queue: job started
 WARN process job{queue=audio processor=AudioProcessor::transcode job_id=01HFFA… attempt=1}: nest_rs::queue: job failed elapsed_ms=12 error=connection refused

The attempt field on the span is how you correlate a retry: apalis re-runs the same job_id with attempt=2, opening a fresh process job span. There is no separate terminal line — the retry budget lives in the apalis RetryLayer; see Retries and failure for the policy behind attempt.

What boot looks like

Each active processor logs one attached line (from the transport) and one registered queue processor line carrying its concurrency and retries budget. A #[process] method that compiled in but whose provider isn’t reachable from this app’s module tree is skipped with a warn:

 INFO nest_rs::transport: attached module-contributed transport transport=QueueWorker
 INFO nest_rs::queue: registered queue processor processor=AudioProcessor::transcode queue=audio concurrency=5 retries=3
 WARN nest_rs::queue: skipped #[process] method: provider unreachable from app's module tree processor=ReportJobs::weekly queue=reports

The skip line is warn — a linked-but-unimported handler is usually a wiring mistake worth surfacing, and it confirms a shared features crate isn’t accidentally activating handlers this binary doesn’t want. See Wiring the worker for the module-gating rule.

Caution

A legacy payload with no wire envelope logs processed an unversioned job payload at warn (fields queue, hint) before it runs. It still executes; drain the queue to clear pre-envelope jobs. A payload tagged with an unsupported version fails the job instead of warning.

Filtering recipes

RUST_LOG=info,nest_rs::queue=debug nestrs run dev worker

info everywhere, debug on the queue path: adds the job started line per poll on top of the job ok / job failed outcomes.

RUST_LOG=nest_rs::queue=warn nestrs run dev worker

Strictly failures, skips, and unversioned warnings — useful for tailing a healthy worker where the only thing you care about is “did anything go wrong.”

Going further

• OpenTelemetry — installing the OTLP appender so these spans and structured logs reach a backend.
• OpenTelemetry / traces — how nest_rs::queue spans appear in a trace UI, attribute conventions.
• OpenTelemetry / logs — structured-log export, severity mapping.
• Retries and failure — the policy behind the attempt field and the failed outcome.