Deployment error Can't determine Firebase Database URL.

Version info

"firebase-admin": "~6.0.0",
"firebase-functions": "^2.0.5",

> firebase --version                    
4.2.0

Steps to reproduce

in my package.json

{
  "name": "functions",
  "description": "Cloud Functions for Firebase",
  "scripts": {
    "lint": "./node_modules/.bin/eslint .",
    "serve": "firebase serve --only functions",
    "shell": "firebase experimental:functions:shell",
    "start": "npm run shell",
    "deploy": "firebase deploy --only functions",
    "logs": "firebase functions:log"
  },
  "dependencies": {
    "@google-cloud/storage": "^1.7.0",
    "@google-cloud/vision": "^0.5.0",
    "child-process-promise": "^2.2.0",
    "firebase-admin": "~6.0.0",
    "firebase-functions": "^2.0.5",
    "mkdirp": "^0.5.1",
    "mkdirp-promise": "^5.0.1"
  },
  "devDependencies": {
    "eslint": "^5.4.0",
    "eslint-plugin-promise": "^4.0.0"
  },
  "engines": {
    "node": "8"
  },
  "private": true,
  "main": "src/index.js"
}

in my index.js

'use strict';
const admin = require('firebase-admin');
admin.initializeApp();

/**
 * Storage triggers
 */
const storageTriggers = require('./storageTriggers');
exports.blurOffensiveImages = storageTriggers.blurOffensiveImages;

/**
 * Database triggers
 */
const databaseTriggers = require('./databaseTriggers');
exports.sendPhotoCommentNotification = databaseTriggers.sendPhotoCommentNotification;

in my databaseTriggers.js

'use strict';

const functions = require('firebase-functions');
const admin = require('firebase-admin');
const db = admin.database();
...

in my storageTriggers.js which is basically https://github.com/firebase/functions-samples/tree/Node-8/moderate-images

'use strict';

const admin = require('firebase-admin');
const functions = require('firebase-functions');
const mkdirp = require('mkdirp-promise');
const vision = require('@google-cloud/vision')();
const spawn = require('child-process-promise').spawn;
const path = require('path');
const os = require('os');
const fs = require('fs');
...

Were you able to successfully deploy your functions?

Previously yes, but not sure what changed from the previous deploy.

Actual behavior

firebase deploy --only functions

=== Deploying to 'vape-tool'...

i  deploying functions
i  functions: ensuring necessary APIs are enabled...
✔  functions: all necessary APIs are enabled
i  functions: preparing functions directory for uploading...
i  functions: packaged functions (74.13 KB) for uploading
✔  functions: functions folder uploaded successfully
i  functions: updating Node.js 8 function blurOffensiveImages(us-central1)...
i  functions: updating Node.js 8 function sendPhotoCommentNotification(us-central1)...
⚠  functions[blurOffensiveImages(us-central1)]: Deployment error.
Function load error: Code in file src/index.js can't be loaded.
Is there a syntax error in your code?
Detailed stack trace: Error: Can't determine Firebase Database URL.
    at FirebaseDatabaseError.FirebaseError [as constructor] (/srv/node_modules/firebase-admin/lib/utils/error.js:39:28)
    at new FirebaseDatabaseError (/srv/node_modules/firebase-admin/lib/utils/error.js:190:23)
    at DatabaseService.ensureUrl (/srv/node_modules/firebase-admin/lib/database/database.js:75:15)
    at DatabaseService.getDatabase (/srv/node_modules/firebase-admin/lib/database/database.js:52:26)
    at FirebaseApp.database (/srv/node_modules/firebase-admin/lib/firebase-app.js:231:24)
    at FirebaseNamespace.fn (/srv/node_modules/firebase-admin/lib/firebase-namespace.js:280:45)
    at Object.<anonymous> (/srv/src/databaseTriggers.js:20:18)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)
⚠  functions[sendPhotoCommentNotification(us-central1)]: Deployment error.
Function load error: Code in file src/index.js can't be loaded.
Is there a syntax error in your code?
Detailed stack trace: Error: Can't determine Firebase Database URL.
    at FirebaseDatabaseError.FirebaseError [as constructor] (/srv/node_modules/firebase-admin/lib/utils/error.js:39:28)
    at new FirebaseDatabaseError (/srv/node_modules/firebase-admin/lib/utils/error.js:190:23)
    at DatabaseService.ensureUrl (/srv/node_modules/firebase-admin/lib/database/database.js:75:15)
    at DatabaseService.getDatabase (/srv/node_modules/firebase-admin/lib/database/database.js:52:26)
    at FirebaseApp.database (/srv/node_modules/firebase-admin/lib/firebase-app.js:231:24)
    at FirebaseNamespace.fn (/srv/node_modules/firebase-admin/lib/firebase-namespace.js:280:45)
    at Object.<anonymous> (/srv/src/databaseTriggers.js:20:18)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)


Functions deploy had errors. To continue deploying other features (such as database), run:
    firebase deploy --except functions

Error: Functions did not deploy properly.

[hiranya911]

I can confirm that simply requiring firebase-functions before initializeApp() fixes the issue.

LOADING TIME: {"projectId":"******","databaseURL":"https://******.firebaseio.com","storageBucket":"******.appspot.com","cloudResourceLocation":"us-central"}
DEFAULT APP OPTIONS: { projectId: '******',
  databaseURL: 'https://******.firebaseio.com',
  storageBucket: '******.appspot.com',
  cloudResourceLocation: 'us-central',
  credential: 
   ApplicationDefaultCredential {
     credential_: MetadataServiceCredential { httpClient: HttpClient {} } } }

Looks like in the prod environment it is the firebase-functions package that sets the environment variable. So if you initialize Admin SDK before requiring that, your code is going to break.

[stanbar]

@kevinajian Yes, it fixed the problem.