PubsubGrpc.Auth (PubsubGrpc v0.4.2)

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Authentication module for Google Cloud Pub/Sub.

Handles token retrieval with ETS-based caching using multiple methods:

  1. Goth library (if available and configured)
  2. gcloud CLI fallback
  3. Returns structured error if no auth available

Configuration

To use Goth for authentication, add it to your supervision tree:

children = [
  {Goth, name: MyApp.Goth, source: {:service_account, credentials}},
  # ... other children
]

Then configure PubsubGrpc to use your Goth instance:

config :pubsub_grpc, :goth, MyApp.Goth

Summary

Functions

clear_cache()

Clears the cached authentication token.

get_token()

Gets an authentication token for Google Cloud API calls.

request_opts()

Gets request options including authentication metadata.

Functions

clear_cache()

@spec clear_cache() :: :ok

Clears the cached authentication token.

Useful when you need to force a token refresh, for example after rotating credentials.

get_token()

@spec get_token() :: {:ok, String.t()} | {:error, PubsubGrpc.Error.t()}

Gets an authentication token for Google Cloud API calls.

Returns a token string in the format "Bearer <token>". Tokens are cached in ETS and refreshed automatically when expired.

Returns

  • {:ok, "Bearer <token>"} - Token retrieved successfully
  • {:error, %PubsubGrpc.Error{}} - Unable to get token

request_opts()

@spec request_opts() :: {:ok, keyword()} | {:error, PubsubGrpc.Error.t()}

Gets request options including authentication metadata.

In emulator mode, returns {:ok, []} (no auth needed). In production, returns {:ok, [metadata: %{"authorization" => token}]}.

Returns

  • {:ok, keyword()} - Options to pass to gRPC stub functions
  • {:error, %PubsubGrpc.Error{}} - Authentication failed