ready-callback

Launch server after all async task ready

Install

$ npm install ready-callback

Usage

Note: ready-callback is using class, so you should use node>=2

var koa = require('koa');
var ready = require('ready-callback')();
var app = koa();
ready.mixin(app);

// register a service
var done = app.readyCallback('service');
serviceLaunch(done);

// callback will be fired after all service launched
app.ready(function() {
  app.listen();
});

Error Handle

If task is called with error, error event will be emit, ready will never be called.

// register a service that will emit error
var done = app.readyCallback('service');
serviceLaunch(function(err) {
  done(err);
});

// listen error event
app.on('error', function(err) {
  // catch error
});

Weak Dependency

If you set a task weak dependency, task will be done without emit error.

var done = app.readyCallback('service', {isWeakDep: true});
serviceLaunch(function(err) {
  done(err);
});

// will be ready
app.ready(function() {
  app.listen();
});

app.on('error', function(err) {
  // never be called
});

You can also set for all ready-callback

var ready = require('ready-callback')({isWeakDep: true});

Ready Status

You can get status every callback end.

app.on('ready_stat', function(data) {
  console.log(data.id); // id of the ended task
  console.log(data.remain); // tasks waiting to be ended
});

Timeout

You can set timeout when a task run a long time.

var ready = require('ready-callback')({timeout: 1000});
ready.mixin(app);
app.on('ready_timeout', function(id) {
  // this will be called after 1s that `service` task don't complete
});

var done = app.readyCallback('service');
serviceLaunch(function() {
  // run a long time
  done();
});

You can also set timeout for every task

ready.mixin(app);
app.on('ready_timeout', function(id) {
  // this will be called after 1s that `service` task don't complete
});

var done = app.readyCallback('service1', {timeout: 1000});
serviceLaunch(done);

lazyStart

You can set a ready-callback object to lazyStart. It will not check ready status immediately, and should start manualy to check ready status.

var ready = require('ready-callback')({ lazyStart: true });
yield sleep(1);
// ready obj is not ready
ready.start();
yield sleep(1);
// ready obj is ready now