Crate openraft_metrics_otel 

OpenTelemetry metrics integration for Openraft.

This crate provides an implementation of the MetricsRecorder trait from openraft, allowing applications to export Raft metrics to any OTEL-compatible backend (Prometheus, Jaeger, OTLP, etc.).

Usage

1. Add this crate to your Cargo.toml:

   [dependencies]
   openraft = "0.10"
   openraft-metrics-otel = "0.1"
   opentelemetry = "0.30"
   opentelemetry_sdk = "0.30"  # For configuring exporters

2. Configure the OpenTelemetry SDK in your application:

   use opentelemetry_sdk::metrics::MeterProvider;
   
   let meter_provider = MeterProvider::builder()
       .with_reader(/* your exporter */)
       .build();
   
   opentelemetry::global::set_meter_provider(meter_provider);

3. Install the recorder in your Raft instance:

   use std::sync::Arc;
   use openraft_metrics_otel::Instruments;
   
   let raft = Raft::new(...).await?;
   raft.set_metrics_recorder(Some(Arc::new(Instruments::new()))).await?;

Metrics

The following metrics are exported:

Histograms

• openraft.log.apply.batch_size - Distribution of log entry counts in Apply commands
• openraft.storage.append.batch_size - Distribution of log entry counts when appending
• openraft.replication.batch_size - Distribution of log entry counts in replication RPCs
• openraft.write.batch_size - Distribution of client write entries merged together

Gauges

• openraft.term.current - Current Raft term
• openraft.log.index.last - Index of last log entry
• openraft.log.index.committed - Index of last committed log entry
• openraft.log.index.applied - Index of last applied log entry
• openraft.snapshot.index - Index of last snapshot
• openraft.log.index.purged - Index of last purged log entry
• openraft.server.state - Server state (0=Learner, 1=Follower, 2=Candidate, 3=Leader)

Counters

• openraft.operation.vote.total - Vote operations
• openraft.operation.heartbeat.total - Heartbeat operations
• openraft.operation.append.total - Append entries operations

Structs

Instruments

OpenTelemetry instruments for recording Raft metrics.