gracedown

Collection of consolidated graceful/forceful shutdown procedures for common Node.js libraries.

Currently supports:

• http server / express
• knex
• send PR for more!

Install

npm install --save gracedown

Usage

gracedown(handlers, [, opts])

Returns a function which can be called to gracefully shutdown your application.

The returned function doesn't call process.exit or output any text by default, unless opts.shutdown is set to true.

• handlers: array of shutdown handlers
• opts.shutdown: if true, changes default option values (defaults to false)
• opts.timeout: timeout in ms before forceful shutdown (defaults to 10000)
• opts.log: logging function
• opts.logError: logging function for errors
• opts.exit: exit function
• opts.exitError: exit function on error

Default values if shutdown is false:

// where noop = () => {}
{
  timeout: 10000,
  log: noop,
  logError: noop,
  exit: noop,
  exitError: noop,
}

Default values if shutdown is true:

{
  timeout: 10000,
  log: console.log.bind(console),
  logError: console.error.bind(console),
  exit: () => process.exit(),
  exitError: () => process.exit(1),
}

Shutdown Handlers

shutdownHandler(opts)

Handlers are Promise-returning functions which accept the following options object:

• opts.log and opts.logError: same as above
• opts.forceful: true if we want to shutdown as quick as possible (defaults to false). For example, the http server handle doesn't wait for connections to close if this is true.

The following functions return shutdown handlers for common Node.js libraries/modules.

stopHttpServer(httpServer)

• httpServer: Node.js http server instance

stopKnex(knex)

• knex: Knex.js object

Example

import gracedown, { stopHttpServer } from 'gracedown'
import http from 'http'

const httpServer = http.createServer((req, res) => res.end('ok'))
httpServer.listen()

const someTimeout = setTimeout(() => {
  console.log('timeout called')
}, 3000)

const shutdown = gracedown([
  stopHttpServer(httpServer),
  // Custom shutdown procedure
  () => {
    clearTimeout(someTimeout)
  }
], { timeout: 5000, shutdown: true })

process.on('SIGTERM', shutdown)
process.on('SIGINT', shutdown)