aws-lambda-mutex

This assures an idempotent execution of lambda functions which have side-effects and are sensitive to being invokes multiple times (which happens and cannot be avoided, see 1 and 2)

dynamodb table

the cloudformation resource for the backing dynamodb table:

    MutexLockTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: DYNAMODB_LOCK_TABLE
        AttributeDefinitions:
          - AttributeName: id
            AttributeType: S
        KeySchema:
          - AttributeName: id
            KeyType: HASH
        BillingMode: PAY_PER_REQUEST
        TimeToLiveSpecification:
          AttributeName: ttl
          Enabled: true

the attributeNames used here (id and ttl) have to match the settings in the config of MutexLockClient make sure the tableNames match as well.

example usage

const { MutexLockClient } = require('@cargonexx/aws-lambda-mutex');

const lockClient = new MutexLockClient({
  dynamodbRegion: "eu-west-1",
  dynamodbTable: process.env.DYNAMODB_LOCK_TABLE,
  dynamodbPartitionKey: "id",
  dynamodbTtlKey: "ttl",
  cleanupAfterSeconds: 60,
  silent: false
});


module.exports.myHandler = lockClient.wrapHandler(async (event, context) => {
  console.log(JSON.stringify(context, null, 2));
  return 'implement me';
});