@govuk-one-login/cri-metrics

This package exports a number of basic utilities for use when publishing AWS CloudWatch metrics in GOV.UK One Login's credential issuers (CRIs).

Further information and source code can be found in the GitHub repository.

Usage

[!WARNING]

Metrics are not sent to CloudWatch immediately. They are collected in memory and only 'flushed' to CloudWatch as a batch when explicitly instructed to do so.

It is recommended to either use the @metrics.logMetrics() class decorator on your Lambda handler, or to call the metrics.publishStoredMetrics() function at the end of the handler.

It is also necessary to manually request that cold start metrics are recorded - this can be done automatically by passing { captureColdStartMetric: true } to the class decorator.

For more information, see the documentation for the underlying @aws-lambda-powertools/metrics module.

The following functions are exported:

| Utility | Purpose | | ------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | captureMetric() | Captures a metric with a given name, and optional value and unit. NB: Metrics captured this way must be flushed at the end of the Lambda execution. | | captureLatency() | Executes a callback, measures the time taken and publishes a metric with the response time. The latency metric is a singleMetric and is therefore flushed straight away. | | metrics | The underlying Lambda Powertools instance. Use this to configure the underlying Powertools module, most importantly by configuring the flushing of metrics. |

Module syntax

This module is currently built to both CJS and ESM standards, so should work universally. However, we expect be moving to ESM-only in the near future.