tideway 0.7.17

A batteries-included Rust web framework built on Axum for building SaaS applications quickly
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172

use super::collector::MetricsCollector;
use axum::body::Body;
use axum::{
    extract::{MatchedPath, Request},
    response::Response,
};
use futures::future::BoxFuture;
use std::sync::Arc;
use std::time::Instant;
use tower::Service;

const UNMATCHED_ROUTE_LABEL: &str = "<unmatched>";

/// Build a Tower layer for metrics collection
pub fn build_metrics_layer(collector: Arc<MetricsCollector>) -> MetricsLayer {
    MetricsLayer { collector }
}

/// Tower layer for metrics collection
#[derive(Clone)]
pub struct MetricsLayer {
    collector: Arc<MetricsCollector>,
}

impl<S> tower::Layer<S> for MetricsLayer {
    type Service = MetricsService<S>;

    fn layer(&self, inner: S) -> Self::Service {
        MetricsService {
            inner,
            collector: self.collector.clone(),
        }
    }
}

/// Tower service for metrics collection
#[derive(Clone)]
pub struct MetricsService<S> {
    inner: S,
    collector: Arc<MetricsCollector>,
}

impl<S> Service<Request> for MetricsService<S>
where
    S: Service<Request, Response = Response<Body>>,
    S::Future: Send + 'static,
{
    type Response = Response<Body>;
    type Error = S::Error;
    type Future = BoxFuture<'static, Result<Self::Response, Self::Error>>;

    fn poll_ready(
        &mut self,
        cx: &mut std::task::Context<'_>,
    ) -> std::task::Poll<Result<(), Self::Error>> {
        self.inner.poll_ready(cx)
    }

    fn call(&mut self, req: Request) -> Self::Future {
        let collector = self.collector.clone();
        let start = Instant::now();
        let method = req.method().to_string();
        let path = req
            .extensions()
            .get::<MatchedPath>()
            .map(|p| p.as_str().to_string())
            .unwrap_or_else(|| UNMATCHED_ROUTE_LABEL.to_string());

        // Increment in-flight requests
        collector.increment_in_flight();

        let fut = self.inner.call(req);

        Box::pin(async move {
            let result = fut.await;
            let duration = start.elapsed();

            match result {
                Ok(response) => {
                    let status = response.status().as_u16();
                    collector.record_request(&method, &path, status, duration);
                    collector.decrement_in_flight();
                    Ok(response)
                }
                Err(error) => {
                    collector.decrement_in_flight();
                    Err(error)
                }
            }
        })
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use axum::Router;
    use axum::body::Body;
    use axum::http::Request;
    use axum::routing::get;
    use prometheus::proto::MetricFamily;
    use tower::ServiceExt;

    #[test]
    fn test_metrics_layer_creation() {
        let collector = Arc::new(MetricsCollector::new().unwrap());
        let _layer = build_metrics_layer(collector);
    }

    #[tokio::test]
    async fn test_metrics_use_matched_path() {
        let collector = Arc::new(MetricsCollector::new().unwrap());
        let app = Router::new()
            .route("/users/{id}", get(|| async { "ok" }))
            .layer(build_metrics_layer(collector.clone()));

        let req = Request::builder()
            .method("GET")
            .uri("/users/123")
            .body(Body::empty())
            .unwrap();
        let _ = app.oneshot(req).await.unwrap();

        let metrics = collector.registry().gather();
        let family = find_metric_family(&metrics, "tideway_http_requests_total")
            .expect("metrics family not found");
        let metric = family.get_metric().first().expect("metric not recorded");
        let path = find_label_value(metric, "path").expect("path label missing");
        assert_eq!(path, "/users/{id}");
    }

    #[tokio::test]
    async fn test_metrics_unmatched_path_uses_constant_label() {
        let collector = Arc::new(MetricsCollector::new().unwrap());
        let app = Router::new()
            .route("/users/{id}", get(|| async { "ok" }))
            .layer(build_metrics_layer(collector.clone()));

        let req = Request::builder()
            .method("GET")
            .uri("/totally-random-path-123")
            .body(Body::empty())
            .unwrap();
        let _ = app.oneshot(req).await.unwrap();

        let metrics = collector.registry().gather();
        let family = find_metric_family(&metrics, "tideway_http_requests_total")
            .expect("metrics family not found");
        let metric = family
            .get_metric()
            .iter()
            .find(|m| find_label_value(m, "status").as_deref() == Some("404"))
            .expect("404 metric not recorded");
        let path = find_label_value(metric, "path").expect("path label missing");
        assert_eq!(path, UNMATCHED_ROUTE_LABEL);
    }

    fn find_metric_family<'a>(
        families: &'a [MetricFamily],
        name: &str,
    ) -> Option<&'a MetricFamily> {
        families.iter().find(|family| family.get_name() == name)
    }

    fn find_label_value(metric: &prometheus::proto::Metric, name: &str) -> Option<String> {
        metric
            .get_label()
            .iter()
            .find(|label| label.get_name() == name)
            .map(|label| label.get_value().to_string())
    }
}