How can I get a reference to a google cloud storage bucket inside my cloud function?

Question

I am trying to replicate the guide Example: image transformation.

I'm ok until I need to call:

import * as gcs from '@google-cloud/storage';
import * as functions from 'firebase-functions';

export const onFileChange = functions.storage.object().onFinalize(object => {

  // this line throws a TypeScript Error
  const destBucket = gcs.bucket(fileBucket);
  ...
}

Property 'bucket' does not exist on type 'typeof Storage'. Did you mean 'Bucket'?

I also tried:

const destBucket = new gcs.Bucket(new gcs.Storage({}), object.bucket);

this compiles but when executing I get an error:

gcs.Storage is not a constructor

It seems as if the API has changed, but I'm updated to the latest versions:

"@google-cloud/storage": "^1.6.0",
"firebase-functions": "^1.0.2",

How can I get a reference to the Bucket so that I can call?:

destBucket
    .file(filePath)
    .download({ destination: tempFilePath })
    .then(() => { ... })

Answer 1

Have you declared gcs with a config object like:

const config = {
    projectId: '....',
    keyFilename: './.......-adminsdk-0vlsn-34c393497c.json'
};

const storage = require('@google-cloud/storage')(config);

You have to use a service-key.json generated in Firebase, as explained in this Cloud Functions official sample https://github.com/firebase/functions-samples/tree/master/generate-thumbnail

"Go to the Firebase Console, select the gear image > project settings > Service Accounts and click Generate New Private Key to download a Service Account Key JSON document."

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In addition the error message most probably means that you have to create an instance of Storage.