Make metrics exporter OpenMetrics-compatible

sorz · Dec 7, 2021 · 7730e07 · 7730e07
1 parent f1cbdd9
commit 7730e07
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Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/README.md b/README.md
@@ -16,7 +16,7 @@ Features:
    first response)
  * Optional status web page (latency, traffic, etc. w/ curl-friendly output)
  * Optional [Graphite](https://graphite.readthedocs.io/) and
-   [Prometheus](https://prometheus.io/) support
+   OpenMetrics ([Prometheus](https://prometheus.io/)) support
    (to build fancy dashboard with [Grafana](https://grafana.com/) for example)
  * Customizable proxy selection algorithm with Lua script (see
    [conf/simple_scroe.lua](conf/simple_score.lua)).
@@ -125,7 +125,7 @@ given IP address and port number. It returns a HTML page for web browser,
 or a ASCII table for `curl`.
 
 The stats page only provides current metrics and a few aggregations. Graphite
-(via `--graphite`) or Prometheus (via `--stats-bind` then `\metrics`) should
+(via `--graphite`) or OpenMetrics (via `--stats-bind` then `\metrics`) should
 be used if you want a full history.
 
 Some examples of Prometheus query (Grafana variant):

diff --git a/src/web/open_metrics.rs b/src/web/open_metrics.rs
@@ -7,6 +7,8 @@ use std::{
 use super::{ServerStatus, Status};
 use crate::{monitor::Monitor, proxy::Delay};
 
+const CONTENT_TYPE: &str = "application/openmetrics-text; version=1.0.0; charset=utf-8";
+
 fn new_metric(buf: &mut String, name: &str, metric_type: &str, help: &str) {
     writeln!(buf, "# HELP moproxy_{} {}", name, help).unwrap();
     writeln!(buf, "# TYPE moproxy_{} {}", name, metric_type).unwrap();
@@ -37,7 +39,6 @@ pub fn exporter(start_time: &Instant, monitor: &Monitor) -> Response<Body> {
         ($name:expr, $help:expr, $func:expr) => {
             new_metric(&mut buf, $name, "gauge", $help);
             each_server(&mut buf, $name, &status.servers, $func);
-            writeln!(&mut buf).unwrap();
         };
     }
 
@@ -80,8 +81,9 @@ pub fn exporter(start_time: &Instant, monitor: &Monitor) -> Response<Body> {
         |s| s.server.status_snapshot().score
     );
 
+    writeln!(buf, "# EOF").unwrap();
     Response::builder()
-        .header("Content-Type", "text/plain; charset=utf-8")
+        .header("Content-Type", CONTENT_TYPE)
         .body(buf.into())
         .unwrap()
 }