@middy/cloudwatch-metrics/index.js

Embedded CloudWatch metrics middleware for the middy framework

import awsEmbeddedMetrics from "aws-embedded-metrics";

const defaults = {};

const cloudwatchMetricsMiddleware = (opts = {}) => {
	const { namespace, dimensions } = { ...defaults, ...opts };
	const cloudwatchMetricsBefore = (request) => {
		const metrics = awsEmbeddedMetrics.createMetricsLogger();

		// If not set, defaults to aws-embedded-metrics
		if (namespace) {
			metrics.setNamespace(namespace);
		}

		// If not set, keeps defaults as defined here https://github.com/awslabs/aws-embedded-metrics-node/#configuration
		if (dimensions) {
			metrics.setDimensions(dimensions);
		}
		Object.assign(request.context, { metrics });
	};

	const cloudwatchMetricsAfter = async (request) => {
		await request.context.metrics.flush();
	};
	const cloudwatchMetricsOnError = async (request) => {
		await cloudwatchMetricsAfter(request);
	};

	return {
		before: cloudwatchMetricsBefore,
		after: cloudwatchMetricsAfter,
		onError: cloudwatchMetricsOnError,
	};
};

export default cloudwatchMetricsMiddleware;