axum-otel-metrics

axum OpenTelemetry metrics middleware with prometheus exporter

follow Semantic Conventions for HTTP Metrics

axum is an ergonomic and modular web framework built with Tokio, Tower, and Hyper

be default, the metrics will be exported at /metrics endpoint. and below metrics will be exported:

requests_total counter

requests_total

http_server_active_requests gauge

The number of active HTTP requests

http_server_request_duration_seconds histogram http_server_request_duration_seconds_bucket http_server_request_duration_seconds_sum http_server_request_duration_seconds_count

http_server_request_size_bytes histogram http_server_request_size_bytes_bucket http_server_request_size_bytes_sum http_server_request_size_bytes_count

http_server_response_size_bytes_ histogram http_server_response_size_bytes__bucket http_server_response_size_bytes__sum http_server_response_size_bytes__count

labels for requests_total, http_server_request_duration_seconds, http_server_request_size_bytes, http_server_response_size_bytes :

http_request_method http_route http_response_status_code server_address

labels for http_server_active_requests :

http_request_method url_scheme

Usage

```rust use axumotelmetrics::HttpMetricsLayerBuilder;

let metrics = HttpMetricsLayerBuilder::new() .build();

let app = Router::new() // export metrics at /metrics endpoint .merge(metrics.routes()) .route("/", get(handler)) .route("/hello", get(handler)) .route("/world", get(handler)) // add the metrics middleware .layer(metrics); ```

Usage with State

```rust use axumotelmetrics::HttpMetricsLayerBuilder;

[derive(Clone)]

pub struct SharedState { }

let state = SharedState { };

let metrics = HttpMetricsLayerBuilder::new() .build();

let app = Router::new() // export metrics at /metrics endpoint .merge(metrics.routes::()) .route("/", get(handler)) .route("/hello", get(handler)) .route("/world", get(handler)) // add the metrics middleware .layer(metrics) .with_state(state.clone()); ```

OpenTelemetry Rust Instrumentation Status and Releases

https://opentelemetry.io/docs/instrumentation/rust/#status-and-releases

| Traces | Metrics | Logs | |--------------------------------------------------------------------------------------------------|---------|---------------------| | Stable | Alpha | Not yet implemented |

OpenTelemetry Metrics Exporter

Push Metric Exporter https://opentelemetry.io/docs/reference/specification/metrics/sdk/#push-metric-exporter

Pull Metric Exporter https://opentelemetry.io/docs/reference/specification/metrics/sdk/#pull-metric-exporter

exporters

https://opentelemetry.io/docs/reference/specification/metrics/sdk_exporters/

In-memory https://opentelemetry.io/docs/reference/specification/metrics/sdk_exporters/in-memory/

Prometheus https://opentelemetry.io/docs/reference/specification/metrics/sdk_exporters/prometheus/

OTLP https://opentelemetry.io/docs/reference/specification/metrics/sdk_exporters/otlp/

Standard output https://opentelemetry.io/docs/reference/specification/metrics/sdk_exporters/stdout/

Metrics Data Model

https://opentelemetry.io/docs/reference/specification/metrics/data-model/