rust_web_server/app/controller/metrics/
mod.rs

1#[cfg(test)]
2mod tests;
3
4use crate::controller::Controller;
5use crate::range::Range;
6use crate::request::{METHOD, Request};
7use crate::response::{Response, STATUS_CODE_REASON_PHRASE};
8use crate::server::ConnectionInfo;
9
10/// Prometheus metrics endpoint: `GET /metrics`.
11///
12/// Returns every metric in the Prometheus text exposition format
13/// (`text/plain; version=0.0.4`), or the protobuf format — the one that
14/// carries native histograms — when the scraper's `Accept` prefers it.
15pub struct MetricsController;
16
17const PROMETHEUS_CONTENT_TYPE: &str = "text/plain; version=0.0.4";
18
19impl Controller for MetricsController {
20    fn is_matching(request: &Request, _connection: &ConnectionInfo) -> bool {
21        request.method == METHOD.get && request.request_uri == "/metrics"
22    }
23
24    fn process(request: &Request, mut response: Response, _connection: &ConnectionInfo) -> Response {
25        MetricsController::fill_response(request, &mut response);
26        response
27    }
28}
29
30impl MetricsController {
31    /// Text format, or protobuf (with native histograms) when `Accept` asks for it.
32    fn fill_response(request: &Request, response: &mut Response) {
33        use crate::metrics::exposition;
34        let (body, content_type) = match request.header("Accept").map(|h| &*h.value) {
35            Some(accept) if exposition::accepts_protobuf(accept) => (exposition::protobuf(), exposition::PROTOBUF_CONTENT_TYPE),
36            _ => (crate::metrics::prometheus_text().into_bytes(), PROMETHEUS_CONTENT_TYPE),
37        };
38        response.status_code = *STATUS_CODE_REASON_PHRASE.n200_ok.status_code;
39        response.reason_phrase = STATUS_CODE_REASON_PHRASE.n200_ok.reason_phrase.to_string();
40        response.content_range_list = vec![
41            Range::get_content_range(body, content_type.to_string())
42        ];
43    }
44
45    pub fn is_matching_request(request: &Request) -> bool {
46        request.method == METHOD.get && request.request_uri == "/metrics"
47    }
48
49    pub fn process_request(request: &Request, mut response: Response) -> Response {
50        MetricsController::fill_response(request, &mut response);
51        response
52    }
53}
rust_web_server/app/controller/metrics/mod.rs

rust_web_server/app/controller/metrics/
mod.rs
