examples/: Add actix-web binary (prometheus#76)

Signed-off-by: ackintosh <sora.akatsuki@gmail.com>

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Added a `with_prefix` method to `Registry` to allow initializing a registry with a prefix. See [PR 70].
 - Added `Debug` implementations on most public types that were missing them. See [PR 71].
+- Added example for actix-web framework. See [PR 76].
 
 ### Removed
 - Remove `Add` trait implementation for a private type which lead to compile time conflicts with existing `Add` implementations e.g. on `String`. See [PR 69].
@@ -20,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [PR 69]: https://github.com/prometheus/client_rust/pull/69
 [PR 70]: https://github.com/prometheus/client_rust/pull/70
 [PR 71]: https://github.com/prometheus/client_rust/pull/71
+[PR 76]: https://github.com/prometheus/client_rust/pull/76
 
 ## [0.16.0]
 

Cargo.toml

@@ -34,6 +34,7 @@ pyo3 = "0.16"
 quickcheck = "1"
 rand = "0.8.4"
 tide = "0.16"
+actix-web = "4"
 
 [build-dependencies]
 prost-build = { version = "0.9.0", optional = true }

examples/actix-web.rs

@@ -0,0 +1,74 @@
+use std::sync::Mutex;
+
+use actix_web::{web, App, HttpResponse, HttpServer, Responder, Result};
+use prometheus_client::encoding::text::{encode, Encode};
+use prometheus_client::metrics::counter::Counter;
+use prometheus_client::metrics::family::Family;
+use prometheus_client::registry::Registry;
+
+#[derive(Clone, Hash, PartialEq, Eq, Encode)]
+pub enum Method {
+    Get,
+    Post,
+}
+
+#[derive(Clone, Hash, PartialEq, Eq, Encode)]
+pub struct MethodLabels {
+    pub method: Method,
+}
+
+pub struct Metrics {
+    requests: Family<MethodLabels, Counter>,
+}
+
+impl Metrics {
+    pub fn inc_requests(&self, method: Method) {
+        self.requests.get_or_create(&MethodLabels { method }).inc();
+    }
+}
+
+pub struct AppState {
+    pub registry: Registry,
+}
+
+pub async fn metrics_handler(state: web::Data<Mutex<AppState>>) -> Result<HttpResponse> {
+    let state = state.lock().unwrap();
+    let mut buf = Vec::new();
+    encode(&mut buf, &state.registry)?;
+    let body = std::str::from_utf8(buf.as_slice()).unwrap().to_string();
+    Ok(HttpResponse::Ok()
+        .content_type("application/openmetrics-text; version=1.0.0; charset=utf-8")
+        .body(body))
+}
+
+pub async fn some_handler(metrics: web::Data<Metrics>) -> impl Responder {
+    metrics.inc_requests(Method::Get);
+    "okay".to_string()
+}
+
+#[actix_web::main]
+async fn main() -> std::io::Result<()> {
+    let metrics = web::Data::new(Metrics {
+        requests: Family::default(),
+    });
+    let mut state = AppState {
+        registry: Registry::default(),
+    };
+    state.registry.register(
+        "requests",
+        "Count of requests",
+        Box::new(metrics.requests.clone()),
+    );
+    let state = web::Data::new(Mutex::new(state));
+
+    HttpServer::new(move || {
+        App::new()
+            .app_data(metrics.clone())
+            .app_data(state.clone())
+            .service(web::resource("/metrics").route(web::get().to(metrics_handler)))
+            .service(web::resource("/handler").route(web::get().to(some_handler)))
+    })
+    .bind(("127.0.0.1", 8080))?
+    .run()
+    .await
+}