Prometheus instrumentation for actix-web. This middleware is heavily influenced by the work in sd2k/rocket_prometheus. We track the same default metrics and allow for adding user defined metrics.
By default two metrics are tracked (this assumes the namespace actix_web_prom):
actix_web_prom_http_requests_total (labels: endpoint, method, status): the total number
of HTTP requests handled by the actix HttpServer.
actix_web_prom_http_requests_duration_seconds (labels: endpoint, method, status): the
request duration for all HTTP requests handled by the actix HttpServer.
First add actix-web-prom to your Cargo.toml:
toml
[dependencies]
actix-web-prom = "0.6.0-rc.2"
You then instantiate the prometheus middleware and pass it to .wrap():
```rust use std::collections::HashMap;
use actixweb::{web, App, HttpResponse, HttpServer}; use actixweb_prom::{PrometheusMetrics, PrometheusMetricsBuilder};
async fn health() -> HttpResponse { HttpResponse::Ok().finish() }
async fn main() -> std::io::Result<()> { let mut labels = HashMap::new(); labels.insert("label1".tostring(), "value1".tostring()); let prometheus = PrometheusMetricsBuilder::new("api") .endpoint("/metrics") .const_labels(labels) .build() .unwrap();
HttpServer::new(move || {
App::new()
.wrap(prometheus.clone())
.service(web::resource("/health").to(health))
})
.bind("127.0.0.1:8080")?
.run()
.await?;
Ok(())
} ```
Using the above as an example, a few things are worth mentioning:
- api is the metrics namespace
- /metrics will be auto exposed (GET requests only) with Content-Type header content-type: text/plain; version=0.0.4; charset=utf-8
- Some(labels) is used to add fixed labels to the metrics; None can be passed instead
if no additional labels are necessary.
A call to the /metrics endpoint will expose your metrics:
```shell $ curl http://localhost:8080/metrics
apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="0.005"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="0.01"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="0.025"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="0.05"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="0.1"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="0.25"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="0.5"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="1"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="2.5"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="5"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="10"} 1 apihttprequestsdurationsecondsbucket{endpoint="/metrics",label1="value1",method="GET",status="200",le="+Inf"} 1 apihttprequestsdurationsecondssum{endpoint="/metrics",label1="value1",method="GET",status="200"} 0.00003 apihttprequestsdurationsecondscount{endpoint="/metrics",label1="value1",method="GET",status="200"} 1
apihttprequests_total{endpoint="/metrics",label1="value1",method="GET",status="200"} 1 ```
You instantiate PrometheusMetrics and then use its .registry to register your custom
metric (in this case, we use a IntCounterVec).
Then you can pass this counter through .data() to have it available within the resource
responder.
```rust use actixweb::{web, App, HttpResponse, HttpServer}; use actixweb_prom::{PrometheusMetrics, PrometheusMetricsBuilder}; use prometheus::{opts, IntCounterVec};
async fn health(counter: web::Data
async fn main() -> std::io::Result<()> { let prometheus = PrometheusMetricsBuilder::new("api") .endpoint("/metrics") .build() .unwrap();
let counter_opts = opts!("counter", "some random counter").namespace("api");
let counter = IntCounterVec::new(counter_opts, &["endpoint", "method", "status"]).unwrap();
prometheus
.registry
.register(Box::new(counter.clone()))
.unwrap();
HttpServer::new(move || {
App::new()
.wrap(prometheus.clone())
.data(counter.clone())
.service(web::resource("/health").to(health))
})
.bind("127.0.0.1:8080")?
.run()
.await?;
Ok(())
} ```
RegistrySome apps might have more than one actix_web::HttpServer.
If that's the case, you might want to use your own registry:
```rust use actixweb::{web, App, HttpResponse, HttpServer}; use actixwebprom::{PrometheusMetrics, PrometheusMetricsBuilder}; use actixweb::rt::System; use prometheus::Registry; use std::thread;
async fn public_handler() -> HttpResponse { HttpResponse::Ok().body("Everyone can see it!") }
async fn private_handler() -> HttpResponse { HttpResponse::Ok().body("This can be hidden behind a firewall") }
fn main() -> std::io::Result<()> { let shared_registry = Registry::new();
let private_metrics = PrometheusMetricsBuilder::new("private_api")
.registry(shared_registry.clone())
.endpoint("/metrics")
.build()
// It is safe to unwrap when __no other app has the same namespace__
.unwrap();
let public_metrics = PrometheusMetricsBuilder::new("public_api")
.registry(shared_registry.clone())
// Metrics should not be available from the outside
// so no endpoint is registered
.build()
.unwrap();
let private_thread = thread::spawn(move || {
let mut sys = System::new();
let srv = HttpServer::new(move || {
App::new()
.wrap(private_metrics.clone())
.service(web::resource("/test").to(private_handler))
})
.bind("127.0.0.1:8081")
.unwrap()
.run();
sys.block_on(srv).unwrap();
});
let public_thread = thread::spawn(|| {
let mut sys = System::new();
let srv = HttpServer::new(move || {
App::new()
.wrap(public_metrics.clone())
.service(web::resource("/test").to(public_handler))
})
.bind("127.0.0.1:8082")
.unwrap()
.run();
sys.block_on(srv).unwrap();
});
private_thread.join().unwrap();
public_thread.join().unwrap();
Ok(())
}
```