trivial-statsd-client

A Rust statsd client for fast-and-loose metrics.

Alternatives:

• https://github.com/tshlabs/cadence
• https://github.com/markstory/rust-statsd
• https://github.com/erik/rust-statsd

Why this one?

• supports subsampling (rate)
• avoids floats wherever possible

Testing it

Use cargo test, duh.

For manual integrated testing with a real local statsd server:

• Clone https://github.com/etsy/statsd
• Copy exmapleConfig.js to config.js and add the dumpMessages: true, directive
• Start the server node stats.js config.js
• Run the cargo tests
• See raw stats appear on statsd stdout

To improve:

• Send multiple metrics per packet, either in explicit transaction or time+volume managed
• Make sampling apply to group of operations (channel open / commit)
• Reuse packet-assembling string buffers OR
• Use iovec crate + friend for scatter/ gather instead of copying to an intermediary strbuf
• For lower sampling rates (< 1/256?), use predictive subsampling: only call rng after every accepted sample to approximate next sample distance, then just inc a counter until we get there, sample, repeat rng would fuzz around target rate according to some factor
  e.g. if rate is 1/2000, next sample would be between 1000 and 3000 points away counter needs to be per metric or per channel to make sure samples are evenly distributed across metrics
• Write more tests