README.md

Middy do-not-wait-for-empty-event-loop middleware

"Do not wait for empty event loop" middleware for the middy framework, the stylish Node.js middleware engine for AWS Lambda

This middleware sets context.callbackWaitsForEmptyEventLoop property to false. This will prevent Lambda from timing out because of open database connections, etc.

Install

To install this middleware you can use NPM:

npm install --save @middy/do-not-wait-for-empty-event-loop

Options

By default the middleware sets the callbackWaitsForEmptyEventLoop property to false only in the before phase, meaning you can override it in handler to true if needed. You can set it in all steps with the options:

• runOnBefore (defaults to true) - sets property before running your handler
• runOnAfter (defaults to false)
• runOnError (defaults to false)

Sample usage

const middy = require('@middy/core')
const doNotWaitForEmptyEventLoop = require('@middy/do-not-wait-for-empty-event-loop')

const handler = middy((event, context, cb) => {
  cb(null, {})
})

handler.use(doNotWaitForEmptyEventLoop({runOnError: true}))

// When Lambda runs the handler it gets context with callbackWaitsForEmptyEventLoop property set to false

handler(event, context, (_, response) => {
  expect(context.callbackWaitsForEmptyEventLoop).toEqual(false)
})

Middy documentation and examples

For more documentation and examples, refers to the main Middy monorepo on GitHub or Middy official website.

Contributing

Everyone is very welcome to contribute to this repository. Feel free to raise issues or to submit Pull Requests.

License

Licensed under MIT License. Copyright (c) 2017-2018 Luciano Mammino and the Middy team.