Invalid Credentials using Google Cloud Platform Buckets - google-cloud-platform

Question

We have a bucket in Google Cloud Platform to manage pictures.
I am trying to upload a picture to it using Curl.
Respective to the official documentation linked here, this is the Curl-command I used:
curl -X POST --data-binary #cat.jpeg \
-H "Authorization: Bearer A_STRING_SUPPOSED_TO_BE_A_KEY" \
-H "Content-Type: image/jpeg" \
"https://storage.googleapis.com/upload/storage/v1/b/upload_zone/o?uploadType=media&name=cat"
This is the answer we get:
{
"error": {
"code": 401,
"message": "Invalid Credentials",
"errors": [
{
"message": "Invalid Credentials",
"domain": "global",
"reason": "authError",
"locationType": "header",
"location": "Authorization"
}
]
}
}
It seems our key is invalid, we are not sure what to use as Authorization key. Where can we find the OAUTH2.0-key required to make use of the Google Cloud Platform Bucket, do we need to generate it somewhere?
Edit:
We have generated a key using the OAuth 2.0-Playground, and it worked! But the key expires every 3000 seconds...

Answer 1

If you are already authenticated to Google using the gcloud sdk, you can get the key like this:
-H "Authorization: Bearer $(gcloud auth print-identity-token)"
So, using your example above, this should work:
curl -X POST --data-binary #cat.jpeg \
-H "Authorization: Bearer $(gcloud auth print-identity-token)" \
-H "Content-Type: image/jpeg" \
"https://storage.googleapis.com/upload/storage/v1/b/upload_zone/o?uploadType=media&name=cat"