11 releases (7 breaking)
0.8.0 | Sep 21, 2022 |
---|---|
0.7.1 | Aug 5, 2021 |
0.7.0 | Jan 26, 2021 |
0.5.0 | Sep 17, 2020 |
0.2.0 | Sep 9, 2019 |
#683 in Debugging
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Epimetheus
An easy-to-use prometheus-compatible metrics library.
Epimetheus is probably the easiest way to get your Rust application
serving metrics. Just scatter your code with instrumentation and call
spawn_http_server()
in main()
.
Watch your hashmaps grow!
metric!(my_data_len).set(my_data.len());
metric!(my_data_cap).set(my_data.capacity());
Monitor the latency of your functions!
let start = Instant::now();
my_function();
metric!(my_function_duration_sum).add(start.elapsed().as_secs_f64());
metric!(my_function_duration_count).add(1.0);
Track the status codes of your responses!
let resp = compute_response();
metric!(responses{code=resp.status()}).add(1.0);
Ok(resp)
Then connect to port 9898 to see what's happening:
$ curl localhost:9898
my_data_cap 1024
my_data_len 764
my_function_duration_count 6032
my_function_duration_sum 8.32
responses{code="200 OK"} 5443
responses{code="404 Not Found"} 587
responses{code="500 Internal Server Error"} 2
Your program can also call epimetheus::query()
to inspect its own metrics.
If you only plan to access the metrics this way, you can skip the call to
spawn_http_server()
.
Features
- Multi-threaded OK! Everyone shares the same set of metrics.
- The format is prometheus-compatible. Point prometheus' watchful eye at your program and get nice graphs.
- Updating metrics is fast (...mostly. See below.)
- The port number can be customised via the
RUST_METRICS_PORT
environment variable. - The code is very readable - under 200 sloc. Take a look!
- Public domain.
Performance
- Updating an unlabelled metric (like
my_data_len
above) is fast (~500ns uncontended, ~5us contended). - Updating a labelled metric (like
responses
above) is slower (~1us uncontended, ~10us contended). - The HTTP server is extremely dumb and can only handle one client at a time; typically this doesn't matter.
Other stuff
Epimetheus is the brother of Prometheus, hence the crate's name.
Contributing
Please send bug reports to ~asayers/public-inbox@lists.sr.ht.
Please send patches to ~asayers/public-inbox@lists.sr.ht, and include the following text:
I dedicate any and all copyright interest in this software to the public domain. I make this dedication for the benefit of the public at large and to the detriment of my heirs and successors. I intend this dedication to be an overt act of relinquishment in perpetuity of all present and future rights to this software under copyright law.
Dependencies
~1MB
~12K SLoC