3 releases (breaking)
new 0.5.0 | Nov 7, 2024 |
---|---|
0.4.0 | Oct 8, 2024 |
0.3.0 | Sep 17, 2024 |
#760 in Filesystem
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biometrics_prometheus
biometrics_prometheus provides a Prometheus emitter for biometrics. It is a crate that is part of the biometrics project.
The emitter takes a prefix and appends "<epoch_millis>.prom" to the prefix to determine where to write next. For
example, the following will write a path like, tmp.foo.1726547192.prom
:
let mut emitter = Emitter::new(Options {
segment_size: 1024,
flush_interval: Duration::from_secs(1),
prefix: Path::new("tmp.foo."),
});
emitter.emit_counter(&Counter::new("foo"), 42).unwrap();
drop(emitter);
The file is opened using create_new
to guarantee it won't overwrite an existing file. The file is locked before any
data is written. Consequently, a reader that uses flock
after opening the file will be able to read the file only
after all data has been written to the file. The included Reader
does exactly that.
There's a pitfall to using Reader
, however. If the reader is opened before the writer finishes writing, the reader
will block and wait. A naive implementation that collects emitted files might have emitters put them into one
directory, and have a script read each file in that directory. If the script reads the file before the writer finishes,
it will block and wait. A locked process that's not rotating its logs in time would then halt system activity.
To avoid this pitfall, use the included Watcher
. The Watcher will watch a directory for files, locking each one in
turn and reading it. The Watcher will not block on a file that's being written to. The Watcher will also allow files
to be removed once they have been processed in an idiomatic way.
Status
Active development.
Scope
The crate is intended to be used as a Prometheus emitter for biometrics.
Warts
Documentation
The latest documentation is always available at docs.rs.
Updating
Dependencies
~80KB