@middy/cloudwatch-metrics/index.js

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)=>{
        try {
            await cloudwatchMetricsAfter(request);
        } catch (e) {}
    };
    return {
        before: cloudwatchMetricsBefore,
        after: cloudwatchMetricsAfter,
        onError: cloudwatchMetricsOnError
    };
};
export default cloudwatchMetricsMiddleware;