Module metrics 

Metrics: exporter installation and pre-registered handle structs for every pipeline stage.

etl-rs instruments through the [metrics] facade — pipeline authors register custom metrics with the same macros and they are exported alongside the framework’s. install wires the exporter selected by configuration; the taxonomy contract lives in docs/METRICS.md and its names in names.

One pipeline per process

The exporter installs a process-global recorder (the metrics facade has one global recorder), matching the framework’s one-pipeline-per-process deployment model. install therefore succeeds at most once per process; a second call returns MetricsError::AlreadyInstalled.

Hot-path discipline

All handles are pre-registered at pipeline build time via the structs in this module (SourceMetrics, SinkShardMetrics, …). The record loop only ever touches resolved Counter/Gauge/Histogram handles, and methods take per-batch aggregates.

Modules

names

Metric and label name constants — the single source of truth for the taxonomy documented in docs/METRICS.md.

Structs

BackpressureMetrics

Backpressure handles (etl_backpressure_*).

CheckpointMetrics

Checkpointer handles (etl_checkpoint_* and end-to-end latency).

ComponentLabels

The standard label set attached to every framework metric.

DeserMetrics

Deserializer-stage handles (etl_deser_*).

MetricsHandle

Handle to the installed exporter. Cheap to clone.

MetricsSettings

Exporter settings, mapped from the metrics config section by the pipeline runtime. Defined here (not in config) so this module has no config dependency.

OperatorMetrics

Operator-stage handles (etl_operator_*).

PipelineMetrics

Pipeline-level handles (etl_pipeline_*).

QueueMetrics

Queue-edge handles (etl_queue_*).

SinkShardMetrics

Sink-shard handles (etl_sink_*), one struct per shard worker.

SourceMetrics

Source-stage handles (etl_source_*).

Enums

E2eBasis

Time basis for etl_e2e_latency_seconds.

Exporter

Which exporter to install.

FlushReason

Why a sink batch was sealed and flushed.

MetricsError

Exporter installation failed.

PipelineState

Lifecycle state of the pipeline, exported via etl_pipeline_state.

Constants

BATCH_BYTES_BUCKETS

Buckets for etl_sink_batch_bytes (powers of 4, 4 KiB .. 256 MiB).

BATCH_ROWS_BUCKETS

Buckets for etl_sink_batch_rows (powers of 4, 64 .. 1Mi rows).

DURATION_SECONDS_BUCKETS

Buckets for *_duration_seconds histograms and etl_e2e_latency_seconds (1 ms .. 60 s, roughly exponential).

Functions

install

Install the configured exporter as this process’s global recorder and return the handle the admin server renders from.