Different Authentication ways for GCP cloud
What to use and when

An developer who wanted to spread the world all the small bit of required information
There are two ways to authenticate the user/service account
How to activate application default credentials:
- Use your user account
gcloud auth application-default login
Use a service account(for any automation script/process)
- set environment variable
GOOGLE_APPLICATION_CREDENTIALS=path/to/your/service_accont_key_file.json
You can also copy the above JSON file - path/to/your/service_accont_key_file.json into ~/.config/gcloud/application_default_credentials.json
On Windows, this might be different, from knowing the path to your config directory.
gcloud info --format="value(config.paths.global_config_dir)"
After all, this following command will give you the access token which can be used for authentication.
gcloud auth application-default print-access-token

