Lambda Debugging Wrapper

A wrapper around lambda to facilitate a better development experience.

Using this library, you are able to run your lambda function code locally but still trigger it with real events, ie. when a file is uploaded to an S3 bucket. This avoids the need to build, package and deploy your lambda function every time you want to test it.

Package can be found here: https://www.npmjs.com/package/lambda-debug-local

Currently supported triggers:

• S3NewFileTrigger
• SQSReceiveMessageTrigger

Usage

Full example:

import { startPollingS3 } from 'lambda-debug-local';
import { handler } from './example-lambda';

console.log('Debugging example-lambda.ts');

startPollingS3({
    handler,
    bucketName: 'my-first-bucket',
    interval: 5000,
    region: 'eu-central-1',
    endpoint: 'http://localhost:4566',
    forcePathStyle: true,
    maxAge: 1000 * 60 * 5, // 5 minutes
    credentials: {
        accessKeyId: 'fake-access-key-id',
        secretAccessKey: 'fake-secret-access-key'
    }
})

Install using npm:

npm install -s lambda-debug-local

Import the startPollingS3 method

import { startPollingS3 } from 'lambda-debug-local';

Call the startPollingS3 method with the following parameters:

startPollingS3({
    handler,
    bucketName: 'my-first-bucket',
    interval: 5000,
    region: 'eu-central-1',
    endpoint: 'http://localhost:4566',
    forcePathStyle: true,
    credentials: {
        accessKeyId: 'fake-access-key-id',
        secretAccessKey: 'fake-secret-access-key'
    }
})

Recommended tools:

This package works great with localstack. Localstack is a local AWS cloud stack that allows you to develop and test your cloud apps offline. It spins up a number of different services, including S3 and SQS, which can be used to trigger your lambda functions.

• https://www.localstack.cloud/
• https://github.com/localstack/localstack-desktop
• https://docs.localstack.cloud/getting-started/installation/ See Makefile for commands to add queues and messages to localstack. Then you can use localstack desktop to browse the queues and messages.

If you use localstack, then the required config is

{
    handler,
    queueUrl: 'http://localhost:4566/000000000000/my-test-queue',
}

Updates:

• 0.0.5: Adds SQS trigger (startPollingSQS). Config is very similar to S3, but with queueUrl instead of bucketName. There is also no forcePathStyle or maxAge. See example below:

{
    handler,
    queueUrl: 'http://localhost:4566/000000000000/my-test-queue',
    interval: 5000,
    region: 'eu-central-1',
    endpoint: 'http://localhost:4566',
    credentials: {
        accessKeyId: 'fake-access-key-id',
        secretAccessKey: 'fake-secret-access-key'
    }
}

Full example:

import { startPollingSQS } from 'lambda-debug-local';
import { handler } from './example-lambda';

console.log('Debugging example-lambda.ts');

startPollingSQS({
    handler,
    queueUrl: 'http://localhost:4566/000000000000/my-test-queue',
    interval: 5000,
    region: 'eu-central-1',
    endpoint: 'http://localhost:4566',
    credentials: {
        accessKeyId: 'fake-access-key-id',
        secretAccessKey: 'fake-secret-access-key'
    }
})

Development:

Please help me to improve this project by contributing to it. The main thing needed is more available triggers.

Getting started:

Required tools:

• Docker
• Node.js
• npm
• Localstack (brew install localstack/tap/localstack-cli)
• Make

npm install make localstack-setup npm run dev