Cloudwatch Error Alarms

Install

npm install @makerx/cloudwatch-error-alarms --save

Usage

In your CDK stack, create the lambda with CloudWatchErrorAlarmLambda and subscribe it to the log group for error level messages.

import { CloudWatchErrorAlarmLambda } from '@makerx/cloudwatch-error-alarms'
import * as destinations from 'aws-cdk-lib/aws-logs-destinations'
import { FilterPattern } from 'aws-cdk-lib/aws-logs'

// My lambda to monitor
const lambda = new lambda.Function(...)

// Set up error lambda to post to Slack
const errorsLambda = new CloudWatchErrorAlarmLambda(this, `${id}-cloud-watch-error-alarms`, {
  erroringFunctionName: lambda.functionName,
  functionName: `${id}-cloud-watch-error-alarms`, // The cloud watch error alarm lambda function name
  slackWebhookUrl: `${slackWebhookUrl}`, // Slack webhook https://slack.com/intl/en-au/help/articles/115005265063-Incoming-webhooks-for-Slack
  errorFilterRegexes: [
    // Regex to ignore error messages
  ],
})

// Allow cloud watch to trigger the alarm lambda on error
lambda.logGroup.addSubscriptionFilter(`${id}-cloud-watch-error-alarms-subscription`, {
  destination: new destinations.LambdaDestination(errorsLambda),
  filterPattern: FilterPattern.stringValue('$.level', '=', 'error'),
})

For developers

Structure

index.ts
is the entry point of the packaage

infrastructure.ts
contains AWS CDK to configure the error alarm lambda

lambda folder
Standalone package that has everything needed for the AWS lambda:

• it's own package.json
• build script to produce a package that can be deploy to AWS lambda and run

How the build works

At the root level, npm run build does:

• Run build for the lambda then copy the output to ./build
• Run tsc for index.ts and infrastructure.ts into ./build The build folder in the content of the NPM package.