Log Message

2 VersionsUtility

Terminal debug sink that logs every incoming message of any stream t through the component logger, prefixed with a per-process sequence index, so a backend stage's output can be inspected during development. Consumes the stream; nothing flows past it.

How it fits

Typical backends

A live image source is tapped so each received frame's contents are echoed to the log while the backend runs.

A throttled stream is logged to confirm the pacing stage emits at the expected cadence before the rest of the graph is wired up.

Caveats

I/O contractThis is a terminal sink: messages stop here and there is no output, so branch the wire upstream if the same data is also needed elsewhere.
State lifetimeThe printed index is process-local and restarts from zero every time the backend is (re)started.
CompatibilityLines are written through the component logger (ppl::logger, info level); whether they are retained depends on the deployment's log-capture setup.
CostLarge payloads such as images or tensors are serialised inline and produce very long lines, and a high message rate can flood the log, so pace the stream upstream when volume is high.
LimitationBehaviour is fully fixed; there is nothing to configure.

Versions

badb58c9defaultlatest
Log through ppl::logger::log instead of std::cout (rule SOURCE.logging). Dropped unresolvable neighbor hint `any`. No contract or behaviour change.
10/3/2026
b35494d5
live-test prerelease 2026-05-24T21:31:22Z
3/27/2026