bragg-timeout

Timeout middleware for bragg framework

When AWS Lambda times out, a simple Task timed out after x seconds is logged. This is often overlooked when setting CloudWatch alarms or when investigating issues. This middleware tries to resolve this problem by allowing the consumer of the middleware to perform an action at some point in time before the lambda reached the time out.

Install

$ npm install bragg-timeout

Usage

const braggTimeout = require('bragg-timeout');
const app = require('bragg');

const app = bragg();

const timerMiddleware = timeout({
	threshold: 1000,
	cb: () => console.error('error - timeout')
});

app.use(ctx => timerMiddleware(ctx).setTimer()) // Set the timer

export const handler = app.listen();

API

braggTimeout(input) => output

input

Type: object

Time out configuration options

input.threshold

Type: number

Time in milliseconds that is used a a threshold before the time out to execute the callback function.

Example:

threshold: 1000 (1 second)

Lambda time out: 10000 (10 seconds)

With the above configuration, the middleware will trigger the callback function at +- 9000 ms (9 seconds) run time.

Since the lambda time out is calculated using the getRemainingTimeInMillis(), this is not 100% accurate and might be a few milliseconds off the exact time out. It also depends on when the middleware is used

input.cb

Type: function

Callback function that is executed at the threshold time.

output

Type: function

A function using the context of the request to set and clear a timer

const timerMiddleware = timeout({
	threshold: 1000,
	cb: () => console.error('error - timeout')
});


app.use(ctx => {
	const timer = timerMiddleware(ctx)

	timer.setTimer() // Set the timer
	timer.removeTimer() // Remove the timer
})