Simplify example-gauth with our recommendations

[ejona86]

Instead of GoogleCredentials.fromStream(), use GoogleCredentials.getApplicationDefault(). We can comment where to put the JSON file and what environment variable to set if they want it somewhere else. We then would note that the JSON file is unnecessary on Google platforms.

Remove refreshAccessToken() and its comment. This will be done automatically when necessary.

GOOGLE_AUTH_EXAMPLE.md would require being updated to match.

[ejona86]

See also: https://grpc.io/docs/guides/auth/

[dapengzhang0]

We can comment where to put the JSON file and what environment variable to set if they want it somewhere else.

What about android client? https://stackoverflow.com/questions/55843782/grpc-error-sample-c-code-not-working-cpp-docs-samples

[ejona86]

@dapengzhang0, the C++ Android client? That's completely separate and uses different APIs. I think it uses the same environment variables and the APIs look similar, though. I'd have to look at https://grpc.io/docs/guides/auth/ to see what APIs to use in C++.

[dapengzhang0]

Regardless of Java or C++, setting environment variables on Android device (not emulator) seems difficult. For java, there is no System.setenv() for Android, but only getenv.

[dapengzhang0]

People have to put the JSON file and set the environment variable if the client calling GoogleCredentials.getApplicationDefault() in not running in GCE.

[sanjaypujare]

@dapengzhang0 but that's no worse than the current example, is it not? I think @ejona86 's point is that within GCP you don't need to do anything (like installing the JSON file) and that might be useful for some people who will use the example as their starting point to develop GCP client apps.

[ejona86]

Oh, I see what you are saying. In general Android is completely different since it doesn't use service accounts. The APIs we document here are for service accounts.

[vinodhabib]

Looking into this ticket and Analysis in progress

[vinodhabib]

Changes are done and PR raised for Review