Lambda nodeJS 4.3 not finishing/executing success callback - firebase

Question

Despite running the log statement immediately above it, my call to callback(null) isn't working. Even tried wrapping it in a try catch block but got nothing.
For reference, here's the full function:
var Firebase = require('firebase');
var request = require('request');
//noinspection AnonymousFunctionJS
/**
*
* #param event - from Lambda
* #param context - from Lambda
* #param callback - from Lambda
*/
exports.handler = function (event, context, callback) {
var AUTOPILOT_API_KEY = getKey(event.stage, 'AUTOPILOT_API_KEY');
var AUTOPILOT_JOURNEY_ID = getKey(event.stage, 'AUTOPILOT_JOURNEY_ID');
activate();
function activate () {
console.log('event:', event);
if (validPayload(event, context)) {
addDefaultPresets(event.uid);
addToAutopilot(event.user, event.uid);
}
}
/**
* checks that the necessary payload has been received
* if YES: returns true and allows process to continue
* if NO: throws context.fail with useful error message(s)
* operating under custom error code naming convention of
* http code + 3 digit ULM error code
* #param event - from Lambda
* #param context - from Lambda
* #returns {boolean} - whether the payload contains the required data
*/
function validPayload (event, context) {
return true; // REDACTED FOR BREVITY
}
/**
* Adds the user to Autopilot as a contact and adds them
* to the journey with trigger id 0001
* #param {Object} user
* #param {string} uid generate by Firebase as unique identifier of registered user
*/
function addToAutopilot (user, uid) {
// REDACTED FOR BREVITY
request({
method: 'POST',
url: 'https://api2.autopilothq.com/v1/trigger/' + AUTOPILOT_JOURNEY_ID + '/contact',
headers: {
'autopilotapikey': AUTOPILOT_API_KEY,
'Content-Type': 'application/json'
},
body: JSON.stringify(payload)
}, function (error, response, body) {
//noinspection MagicNumberJS
if (response.statusCode !== 200) {
errorResponse.status = response.statusCode;
errorResponse.error = {
errorMessage: error,
user: event.user,
response: response,
body: body
};
console.log('should throw ERROR callback');
context.fail(JSON.stringify(errorResponse));
} else {
console.log('should throw SUCCESS callback');
console.log(JSON.stringify({
status: response.statusCode,
message: "User successfully added to Autopilot account & journey"
}));
callback(null);
}
console.log('Finished addToAutopilot()');
});
}
/**
* Adds a collection of presets the the account of the new user
* #param uid {String} - Firebase UID
*/
function addDefaultPresets (uid) {
// REDACTED FOR BREVITY
var presets = ref.child('users').child(uid).child('presets');
console.log('Starting addDefaultPresets()');
activate();
function activate () {
console.info('activating...');
// for each field
fields.forEach(function (field) {
// iterate over each preset
presetData[field].forEach(function (label) {
// and add to firebase db via addDefaultPreset() if unique
presetIsUnique(field, label);
})
});
console.log('Finished addDefaultPresets()');
}
function presetIsUnique (field, label) {
presets.child(field).orderByChild('label')
.equalTo(label)
.once('value', function (snapshot) {
var val = snapshot.val();
if (!val) {
addDefaultPreset(field, label);
} else {
console.error('already exists', field, label);
}
});
}
function addDefaultPreset (field, label) {
//noinspection MagicNumberJS
presets.child(field).push().set({
creator: 'default',
dateAdded: Math.floor(Date.now() / 1000),
label: label
}, setCallback);
}
function setCallback (err) {
if (err) {
console.error(err);
} else {
console.info('added preset');
}
}
}
function getKey (stage, keyId) {
var keys = {
AUTOPILOT_API_KEY: {
staging: 'dev123',
prod: 'prod123'
},
AUTOPILOT_JOURNEY_ID: {
staging: 'XXX',
product: 'XXXX'
},
FIREBASE_URL: {
staging: 'https://staging.firebaseio.com/',
prod: 'https://prod.firebaseio.com/'
}
};
if (stage === 'prod') {
return keys[keyId][stage];
} else {
return keys[keyId]['staging'];
}
}
};

Answer 1

It seems like firebase is keeping something in the event loop. By default, lambda waits until the event loop is empty before terminating. You can set context.callbackWaitsForEmptyEventLoop = false to tell lambda to terminate the function soon after the callback is called, even if there is still items in the event loop.

Answer 2

After hours and hours of debugging here is something that worked for me:
var firebase = require('firebase');
var app = firebase.initializeApp(config);
...
...
...
app.delete().then(function(){
var response = {
statusCode: 200,
body: JSON.stringify({
message: 'Success'
}),
};
callback(null, response);
});
You can read more about delete in the official documentation:
Make the given App unusable and free the resources of all associated
services.
Hope this is helpful!