metrics_cloudwatch_embedded

The interface is not stable

This is a Minimum Viable Product for feedback, experimentation and iteration

Purpose

Provide a backend for the metrics facade crate, to emit metrics in CloudWatch Embedded Metrics Format

Intended for use with the lambda_runtime, however Collector::flush_to(...) could be used for anything that writes logs that end up in CloudWatch.

How to use

let metrics = metrics_cloudwatch_embedded::Builder::new()
    .cloudwatch_namespace("MyApplication")
    .init()
    .unwrap();

metrics::increment_counter!("requests", "Method" => "Default");

metrics
    .set_property("RequestId", "ABC123")
    .flush();

Limitations

• Histograms retain up to 100 values (the maximum for a single metric document) between calls to Collector::flush(), overflow is silently dropped
• Dimensions set at initialization via Builder::with_dimension(...) may not overlap with metric labels
• Only the subset of metric units in metrics::Unit are supported [https://docs.aws.amazon.com/AmazonCloudWatch/latest/APIReference/API_MetricDatum.html]
• Registering different metric types with the same metrics::Key will silently fail

Thanks

• Simon Andersson (ramn) and contributors - For the metrics_cloudwatch crate I used as a reference
• Toby Lawrence (tobz) - For answering my metrics crate questions before I even had something working