Google Cloud Functions ACP local testing WON'T WORK!

[finnDiesel234xX]

I have a NextJS / Typescript webapp. The backend of the webapp is supposed to call my Google Cloud Function, called "python-http-function" under project name "python-serverless-test-1". This is not a public function. I am testing my webapp locally, meaning with "npm run dev" and testing out calling my cloud function.

I am using ADC (Application Default Credentials), which finds the credentials in whatever current environment is being run. For local/development in this case, I provided user credentials to ADC by running the "gcloud auth application-default login" command, which created a file in $HOME/.config/gcloud/application_default_credentials.json. This file exists, I verified.

When I actually execute the call to python-http-function with the following code, however, it errors:

// source for this code: https://cloud.google.com/functions/docs/securing/authenticating#generating_tokens_programmatically
  
const targetAudience = 'https://us-west1-python-serverless-test-1.cloudfunctions.net/python-http-function'
  const url = targetAudience;
  const auth = new GoogleAuth();
  const client = await auth.getIdTokenClient(targetAudience);

  // Create a FormData object to hold the form data.
  const formData = new FormData();

  // Add the form data to the FormData object.
  formData.append('pdf', 'data');

  // Make the request to the Cloud function.

  const res = await client.request({
    url: url,
    method: 'POST',
    body: formData,
  });

Error:
error Error: Cannot fetch ID token in this environment, use GCE or set the GOOGLE_APPLICATION_CREDENTIALS environment variable to a service account credentials JSON file.

 I verified that gcloud can find the JSON credentials file by running gcloud auth application-default print-access-token and seeing it print it out. What is going on here? What am I missing? 

Thanks!

[christianpaula]

Hi @finnDiesel234xX,

Welcome to Google Cloud Community!

You may try this to resolve the issue of calling a Google Cloud Function from your local Next.js/TypeScript web app with Application Default Credentials (ADC):

1. Set the GOOGLE_APPLICATION_CREDENTIALS environment variable to the path of your service account credentials JSON file.
2. Ensure you have the required dependencies installed, such as google-auth-library.
3. You can explicitly specify the credentials when creating a new instance of GoogleAuth by providing the keyFilename option with the path to your credentials JSON file.
4. Make sure your service account associated with the credentials JSON file has the necessary permissions to invoke the Google Cloud Function.
5. Update your Google Cloud SDK to the latest version using gcloud components update.
6. Test your application locally using the same environment where you set the GOOGLE_APPLICATION_CREDENTIALS environment variable.

Hope this helps!

[finnDiesel234xX]

Thank you for your response! To be clear, I have already created a service account, given it "editor" permission and attached it to my gen2 cloud function. Additionally, I have already fully set up ADC for local development following this. 

However, even after setting 

GOOGLE_APPLICATION_CREDENTIALS = "/Users/me/.config/gcloud/application_default_credentials.json"

inside of .env.development.local file and verifying via console.log() that process.env.GOOGLE_APPLICATION_CREDENTIALS indeed holds this path, I STILL get this error: 

- error Error: Cannot fetch ID token in this environment, use GCE or set the GOOGLE_APPLICATION_CREDENTIALS environment variable to a service account credentials JSON file.

Again, my code is as follows:

  const targetAudience = 'https://us-west1-python-serverless-test-1.cloudfunctions.net/python-http-function'
  const url = targetAudience;

  const auth = new GoogleAuth();
  const client = await auth.getIdTokenClient(targetAudience);
  const formData = new FormData();
  formData.append('pdf', 'data');
  const res = await client.request({
    url: url,
    method: 'POST',
    body: formData,
  });

I am following this to a tee. 

I also ran gcloud components update for good measure. Please let me know what other information I can provide. 

I am completely lost on what is wrong here.