Deployment error: Failed to configure GCS trigger Bucket: undefined

I am an iOS developer and I started developing my apps with Firebase. Firebase recently got a new feature, cloud features.

I want to create my first cloud function that generates a thumbnail from an uploaded photo as a souvenir. I copied the sample code from here .

So mine index.js

looks like this:

const functions = require('firebase-functions');
const mkdirp = require('mkdirp-promise');
const admin = require('firebase-admin');
const gcs = require('@google-cloud/storage')();
const spawn = require('child-process-promise').spawn;
const _ = require('lodash');
const LOCAL_TMP_FOLDER = '/tmp/';

// Max height and width of the thumbnail in pixels.
const THUMB_MAX_HEIGHT = 200;
const THUMB_MAX_WIDTH = 200;
// Thumbnail prefix added to file names.
const THUMB_PREFIX = 'thumb_';

admin.initializeApp(functions.config().firebase);

exports.generateThumbnail = functions.storage.object().onChange(event => {
  const filePath = event.data.name;
  const filePathSplit = filePath.split('/');
  const fileName = filePathSplit.pop();
  const fileDir = filePathSplit.join('/') + (filePathSplit.length > 0 ? '/' : '');
  const thumbFilePath = `${fileDir}${THUMB_PREFIX}${fileName}`;
  const tempLocalDir = `${LOCAL_TMP_FOLDER}${fileDir}`;
  const tempLocalFile = `${tempLocalDir}${fileName}`;
  const tempLocalThumbFile = `${LOCAL_TMP_FOLDER}${thumbFilePath}`;

    // Exit if this is triggered on a file that is not an image.
  if (!event.data.contentType.startsWith('image/')) {
    console.log('This is not an image.');
    return;
  }

    // Exit if the image is already a thumbnail.
  if (fileName.startsWith(THUMB_PREFIX)) {
    console.log('Already a Thumbnail.');
    return;
  }

    // Create the temp directory where the storage file will be downloaded.
  return mkdirp(tempLocalDir).then(() => {
    // Download file from bucket.
    const bucket = gcs.bucket(event.data.bucket);
    return bucket.file(filePath).download({
      destination: tempLocalFile
    }).then(() => {
      console.log('The file has been downloaded to', tempLocalFile);
      // Generate a thumbnail using ImageMagick.
      return spawn('convert', [tempLocalFile, '-thumbnail', `${THUMB_MAX_WIDTH}x${THUMB_MAX_HEIGHT}>`, tempLocalThumbFile]).then(() => {
        console.log('Thumbnail created at', tempLocalThumbFile);
        // Uploading the Thumbnail.
        return bucket.upload(tempLocalThumbFile, {
          destination: thumbFilePath
        }).then(() => {
          console.log('Thumbnail uploaded to Storage at', thumbFilePath);
        });
      });
    });
  });
});

      

        
        
        
      

    

My package.json

:

{
  "name": "functions",
  "description": "Cloud Functions for Firebase",
  "dependencies": {
    "@google-cloud/storage": "^0.8.0",
    "child-process-promise": "^2.2.0",
    "firebase-admin": "^4.1.2",
    "firebase-functions": "^0.5.1",
    "lodash": "^4.17.4",
    "mkdirp": "^0.5.1",
    "mkdirp-promise": "^4.0.0"
  },
  "private": true
}

      

        
        
        
      

    

And after firebase deploy --only functions

I got the following:

i  deploying functions
i  functions: ensuring necessary APIs are enabled...
i  runtimeconfig: ensuring necessary APIs are enabled...
✔  functions: all necessary APIs are enabled
✔  runtimeconfig: all necessary APIs are enabled
i  functions: preparing functions directory for uploading...
i  functions: packaged functions (2.64 KB) for uploading
✔  functions: functions folder uploaded successfully
i  starting release process (may take several minutes)...
⚠  functions[generateThumbnail]: Deploy Error: Failed to configure trigger GCS           Bucket: undefined

      

        
        
        
      

    

What am I doing wrong?

PS. Im JS newbie. Perhaps this problem is trivial .: