https://github.com/ttys3/axum-otel-metrics
axum OpenTelemetry Metrics middleware with prometheus exporter
https://github.com/ttys3/axum-otel-metrics
axum axum-middleware metric metrics middleware opentelemetry prometheus
Last synced: 8 days ago
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axum OpenTelemetry Metrics middleware with prometheus exporter
- Host: GitHub
- URL: https://github.com/ttys3/axum-otel-metrics
- Owner: ttys3
- Created: 2022-10-12T20:26:40.000Z (about 3 years ago)
- Default Branch: main
- Last Pushed: 2025-09-29T16:01:26.000Z (20 days ago)
- Last Synced: 2025-10-10T08:51:12.416Z (10 days ago)
- Topics: axum, axum-middleware, metric, metrics, middleware, opentelemetry, prometheus
- Language: Rust
- Homepage:
- Size: 355 KB
- Stars: 34
- Watchers: 1
- Forks: 9
- Open Issues: 13
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
Awesome Lists containing this project
README
# axum-otel-metrics
[](https://github.com/ttys3/axum-otel-metrics/actions/workflows/rust.yml)
[](https://crates.io/crates/axum-otel-metrics)
[](https://docs.rs/axum-otel-metrics)
axum OpenTelemetry metrics middleware with OTLP exporter
follows [Semantic Conventions for HTTP Metrics](https://github.com/open-telemetry/semantic-conventions/blob/main/docs/http/http-metrics.md)
[axum](https://github.com/tokio-rs/axum) is an ergonomic and modular web framework built with Tokio, Tower, and Hyper
## Note: Prometheus exporter is removed now
> Development of the Prometheus exporter has been discontinued. See the related
> [issue](https://github.com/open-telemetry/opentelemetry-rust/issues/2451). This
> crate depends on the unmaintained `protobuf` crate and has unresolved security
> vulnerabilities. Version 0.29 will be the final release.
>
> For Prometheus integration, we strongly recommend using the [OTLP] exporter
> instead. Prometheus [natively supports
> OTLP](https://prometheus.io/docs/guides/opentelemetry/#enable-the-otlp-receiver),
> providing a more stable and actively maintained solution.
> for more details please check https://github.com/open-telemetry/opentelemetry-rust/blob/opentelemetry-0.30.0/opentelemetry-prometheus/README.md
> and https://github.com/ttys3/axum-otel-metrics/issues/176
## Usage
Uses the [OTLP Exporter](https://opentelemetry.io/docs/specs/otel/metrics/sdk_exporters/otlp/) to send metrics to OpenTelemetry collector.
You can configure it via environment variables:
- `OTEL_EXPORTER_OTLP_ENDPOINT` or `OTEL_EXPORTER_OTLP_METRICS_ENDPOINT`
`OTEL_EXPORTER_OTLP_ENDPOINT` default value:
- gRPC: `http://localhost:4317`
- HTTP: `http://localhost:4318`
`OTEL_EXPORTER_OTLP_METRICS_ENDPOINT` default value:
- gRPC: `http://localhost:4317`
- HTTP: `http://localhost:4318/v1/metrics`
> For more details, see https://opentelemetry.io/docs/languages/sdk-configuration/otlp-exporter/#endpoint-configuration
```rust
use axum_otel_metrics::HttpMetricsLayerBuilder;
use axum::{response::Html, routing::get, Router};
use opentelemetry_sdk::metrics::{PeriodicReader, SdkMeterProvider, Temporality};
use opentelemetry::global;
let exporter = opentelemetry_otlp::MetricExporter::builder()
.with_http()
.with_temporality(Temporality::default())
.build()
.unwrap();
let reader = PeriodicReader::builder(exporter)
.with_interval(std::time::Duration::from_secs(30))
.build();
let provider = SdkMeterProvider::builder()
.with_reader(reader)
.build();
// TODO: ensure defer run `provider.shutdown()?;`
global::set_meter_provider(provider.clone());
let metrics = HttpMetricsLayerBuilder::new()
.build();
let app = Router::new()
.route("/", get(handler))
.route("/hello", get(handler))
.route("/world", get(handler))
// add the metrics middleware
.layer(metrics);
async fn handler() -> Html<&'static str> {
Html("
Hello, World!
")
}
```
## Exported Metrics
The following metrics are exported following OpenTelemetry semantic conventions:
**http.server.active_requests** (UpDownCounter)
- The number of active HTTP requests
- Labels: `http.request.method`, `url.scheme`
**http.server.request.duration** (Histogram)
- The HTTP request latencies in seconds
- Labels: `http.request.method`, `http.route`, `http.response.status_code`, `server.address`
**http.server.request.body.size** (Histogram)
- The HTTP request sizes in bytes
- Labels: `http.request.method`, `http.route`, `http.response.status_code`, `server.address`
**http.server.response.body.size** (Histogram)
- The HTTP response sizes in bytes
- Labels: `http.request.method`, `http.route`, `http.response.status_code`, `server.address`
## OpenTelemetry Rust Instrumentation Status and Releases
https://opentelemetry.io/docs/instrumentation/rust/#status-and-releases
| Traces | Metrics | Logs |
|--------|---------|------|
| [Beta](https://github.com/open-telemetry/oteps/blob/main/text/0232-maturity-of-otel.md#beta) | Beta | Beta |
## 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/
- OTLP https://opentelemetry.io/docs/reference/specification/metrics/sdk_exporters/otlp/
- Standard output https://opentelemetry.io/docs/reference/specification/metrics/sdk_exporters/stdout/
where is prometheus exporter?
## Metrics Data Model
https://opentelemetry.io/docs/reference/specification/metrics/data-model/
## Related Projects
- https://github.com/nlopes/actix-web-prom - Actix-web middleware to expose Prometheus metrics
- https://github.com/sd2k/rocket_prometheus - Prometheus fairing and handler for Rocket
- https://github.com/Ptrskay3/axum-prometheus - axum-prometheus relies on metrics.rs and its ecosystem to collect and export metrics