g-rath / repo-event-notifier-lambda

repo-event-notifier-lambda

An AWS lambda that monitors repos & talks to you in Slack

This project is written in TypeScript, and is expected to be deployed on an AWS Lambda.

Setup

Run npm install.

• Setup necessary environment variables from functions.env directly in AWS Lambda
• Add AWS environment variables for deployment, see node-lambda package for further configuration options:
  • AWS_ACCESS_KEY_ID
  • AWS_SECRET_ACCESS_KEY
  • AWS_REGION (e.g. ap-southeast-2)
  • AWS_DEFAULT_REGION (e.g. ap-southeast-2)
  • AWS_FUNCTION_NAME (use function name only, not the ARN)
  • AWS_ROLE_ARN
  • AWS_RUNTIME (most likely nodejs10.x)
  • EXCLUDE_GLOBS recommended value: {.*,*,}.{env*,eslint*,json,ts,js.*,md,iml} .idea scripts coverage test
  • PACKAGE_DIRECTORY recommended value: build

Testing

This project uses jest to test itself, with specification files living in the test directory. Tests are written in TypeScript, which is run using ts-jest.

Tests can be run using the test script:

npm test

Compiling

Since this project is written in TypeScript, and ts-node can't be used on AWS Lambda, you need to compile the project before deployment.

This can be done using the compile script:

npm run compile

This will call ttsc compile, using the tsconfig.json located in the src folder, and result in every .ts file in the src folder being compiled into Javascript.

The src/tsconfig.json extends from the root tsconfig.json, as so not compile the contents of the test folder, which are not needed for deployment.

Note that this project uses ts transformers, which are applied using ttypescript. This means that you have to use ttsc instead of tsc when compiling the project.

Deploying

Note: Before deployment, make sure you setup the deploy.env file, based off the deploy.env.example file provided.

Deployment is done using node-lambda. Since AWS Lambda doesn't support ts-node, this project must be compiled before being deployed. Refer to the Compiling section of this README for more info.

Deployment is composed of three steps:

1. Compile the project (as detailed in the previous section),
2. Package the project into a .zip file,
3. Deploy the .zip file onto AWS Lambda.

Steps 2 & 3 are handled by node-lambda, and make use of your .env file.

A script exists for each of the above steps, along with another script that executes all three in series:

npm run compile
npm run package
npm run depoly

# all together now:
npm run the-works

Architecture

This lambda is invoked by api-gateway, via webhooks, and uses an ordered series of request handlers to handle incoming requests.

When a request is made, the lambda passes said request to each request handler, until one of them returns a valid response.