camel-prometheus

Prometheus metrics integration for rust-camel.

Overview

Implements MetricsCollector trait to export rust-camel metrics in Prometheus format.

New in 0.3.0: PrometheusService with Lifecycle trait for automatic server management.

Quick Start

Simple API (Recommended)

use camel_prometheus::PrometheusService;
use camel_core::context::CamelContext;

// Prometheus server starts/stops automatically with context
let ctx = CamelContext::new()
    .with_lifecycle(PrometheusService::new(9090))
    .with_tracing();

ctx.start().await?;
// Server running on http://0.0.0.0:9090/metrics

ctx.stop().await?;
// Server stopped automatically

Manual Setup (Backward Compatible)

use camel_prometheus::{PrometheusMetrics, MetricsServer};
use camel_core::context::CamelContext;
use std::sync::Arc;
use std::net::SocketAddr;

let prometheus = Arc::new(PrometheusMetrics::new());
let ctx = CamelContext::with_metrics(Arc::clone(&prometheus));

// Start server manually
let addr: SocketAddr = "0.0.0.0:9090".parse().unwrap();
tokio::spawn(async move {
    MetricsServer::run(addr, prometheus).await;
});

PrometheusService

PrometheusService implements the Lifecycle trait, which follows Apache Camel's Service pattern:

• Automatically starts HTTP server when CamelContext.start() is called
• Automatically stops when CamelContext.stop() is called
• Auto-registers PrometheusMetrics as MetricsCollector

Metrics Exposed

Endpoint

GET /metrics

Returns Prometheus text format metrics.

Architecture

PrometheusService (Lifecycle trait)
    ↓
    ├── Manages HTTP server lifecycle (start/stop)
    ├── Auto-registers MetricsCollector
    └── MetricsServer (uses tower::Service internally via axum)

Note: Uses Lifecycle trait (not Service) to avoid confusion with tower::Service.

Health Endpoints

The PrometheusService exposes three health endpoints:

Kubernetes Integration

livenessProbe:
  httpGet:
    path: /healthz
    port: 9090
  initialDelaySeconds: 5
  periodSeconds: 10

readinessProbe:
  httpGet:
    path: /readyz
    port: 9090
  initialDelaySeconds: 5
  periodSeconds: 5

Health Report Format

{
  "status": "Healthy",
  "services": [
    {
      "name": "prometheus",
      "status": "Started"
    }
  ]
}