feat: avoid authentication with storage emulator (#679)

* feat: avoid authentication with storage emulator

* add unit tests

* add more unit tests

* add support for corner case project set in envvar

* add _helpers unit test

* allow flexibility for locational endpoints

google/cloud/storage/_helpers.py

@@ -23,6 +23,7 @@
 from urllib.parse import urlsplit
 
 from google import resumable_media
+from google.auth import environment_vars
 from google.cloud.storage.constants import _DEFAULT_TIMEOUT
 from google.cloud.storage.retry import DEFAULT_RETRY
 from google.cloud.storage.retry import DEFAULT_RETRY_IF_METAGENERATION_SPECIFIED
@@ -62,6 +63,12 @@ def _get_storage_host():
     return os.environ.get(STORAGE_EMULATOR_ENV_VAR, _DEFAULT_STORAGE_HOST)
 
 
+def _get_environ_project():
+    return os.getenv(
+        environment_vars.PROJECT, os.getenv(environment_vars.LEGACY_PROJECT),
+    )
+
+
 def _validate_name(name):
     """Pre-flight ``Bucket`` name validation.
 

google/cloud/storage/client.py

@@ -31,6 +31,7 @@
 from google.cloud._helpers import _LocalStack, _NOW
 from google.cloud.client import ClientWithProject
 from google.cloud.exceptions import NotFound
+from google.cloud.storage._helpers import _get_environ_project
 from google.cloud.storage._helpers import _get_storage_host
 from google.cloud.storage._helpers import _DEFAULT_STORAGE_HOST
 from google.cloud.storage._helpers import _bucket_bound_hostname_url
@@ -121,13 +122,6 @@ def __init__(
         if project is _marker:
             project = None
 
-        super(Client, self).__init__(
-            project=project,
-            credentials=credentials,
-            client_options=client_options,
-            _http=_http,
-        )
-
         kw_args = {"client_info": client_info}
 
         # `api_endpoint` should be only set by the user via `client_options`,
@@ -148,6 +142,27 @@ def __init__(
                 api_endpoint = client_options.api_endpoint
                 kw_args["api_endpoint"] = api_endpoint
 
+        # Use anonymous credentials and no project when
+        # STORAGE_EMULATOR_HOST or a non-default api_endpoint is set.
+        if (
+            kw_args["api_endpoint"] is not None
+            and kw_args["api_endpoint"].find("storage.googleapis.com") < 0
+        ):
+            if credentials is None:
+                credentials = AnonymousCredentials()
+            if project is None:
+                project = _get_environ_project()
+            if project is None:
+                no_project = True
+                project = "<none>"
+
+        super(Client, self).__init__(
+            project=project,
+            credentials=credentials,
+            client_options=client_options,
+            _http=_http,
+        )
+
         if no_project:
             self.project = None
 

tests/unit/test__helpers.py

@@ -46,6 +46,34 @@ def test_w_env_var(self):
         self.assertEqual(host, HOST)
 
 
+class Test__get_environ_project(unittest.TestCase):
+    @staticmethod
+    def _call_fut():
+        from google.cloud.storage._helpers import _get_environ_project
+
+        return _get_environ_project()
+
+    def test_wo_env_var(self):
+        with mock.patch("os.environ", {}):
+            project = self._call_fut()
+
+        self.assertEqual(project, None)
+
+    def test_w_env_var(self):
+        from google.auth import environment_vars
+
+        PROJECT = "environ-project"
+
+        with mock.patch("os.environ", {environment_vars.PROJECT: PROJECT}):
+            project = self._call_fut()
+        self.assertEqual(project, PROJECT)
+
+        with mock.patch("os.environ", {environment_vars.LEGACY_PROJECT: PROJECT}):
+            project = self._call_fut()
+
+        self.assertEqual(project, PROJECT)
+
+
 class Test_PropertyMixin(unittest.TestCase):
     @staticmethod
     def _get_default_timeout():

tests/unit/test_client.py

@@ -236,6 +236,65 @@ def test_ctor_mtls(self):
         self.assertEqual(client._connection.ALLOW_AUTO_SWITCH_TO_MTLS_URL, False)
         self.assertEqual(client._connection.API_BASE_URL, "http://foo")
 
+    def test_ctor_w_emulator_wo_project(self):
+        from google.auth.credentials import AnonymousCredentials
+        from google.cloud.storage._helpers import STORAGE_EMULATOR_ENV_VAR
+
+        # avoids authentication if STORAGE_EMULATOR_ENV_VAR is set
+        host = "http://localhost:8080"
+        environ = {STORAGE_EMULATOR_ENV_VAR: host}
+        with mock.patch("os.environ", environ):
+            client = self._make_one()
+
+        self.assertIsNone(client.project)
+        self.assertEqual(client._connection.API_BASE_URL, host)
+        self.assertIsInstance(client._connection.credentials, AnonymousCredentials)
+
+        # avoids authentication if storage emulator is set through api_endpoint
+        client = self._make_one(
+            client_options={"api_endpoint": "http://localhost:8080"}
+        )
+        self.assertIsNone(client.project)
+        self.assertEqual(client._connection.API_BASE_URL, host)
+        self.assertIsInstance(client._connection.credentials, AnonymousCredentials)
+
+    def test_ctor_w_emulator_w_environ_project(self):
+        from google.auth.credentials import AnonymousCredentials
+        from google.cloud.storage._helpers import STORAGE_EMULATOR_ENV_VAR
+
+        # avoids authentication and infers the project from the environment
+        host = "http://localhost:8080"
+        environ_project = "environ-project"
+        environ = {
+            STORAGE_EMULATOR_ENV_VAR: host,
+            "GOOGLE_CLOUD_PROJECT": environ_project,
+        }
+        with mock.patch("os.environ", environ):
+            client = self._make_one()
+
+        self.assertEqual(client.project, environ_project)
+        self.assertEqual(client._connection.API_BASE_URL, host)
+        self.assertIsInstance(client._connection.credentials, AnonymousCredentials)
+
+    def test_ctor_w_emulator_w_project_arg(self):
+        from google.auth.credentials import AnonymousCredentials
+        from google.cloud.storage._helpers import STORAGE_EMULATOR_ENV_VAR
+
+        # project argument overrides project set in the enviroment
+        host = "http://localhost:8080"
+        environ_project = "environ-project"
+        project = "my-test-project"
+        environ = {
+            STORAGE_EMULATOR_ENV_VAR: host,
+            "GOOGLE_CLOUD_PROJECT": environ_project,
+        }
+        with mock.patch("os.environ", environ):
+            client = self._make_one(project=project)
+
+        self.assertEqual(client.project, project)
+        self.assertEqual(client._connection.API_BASE_URL, host)
+        self.assertIsInstance(client._connection.credentials, AnonymousCredentials)
+
     def test_create_anonymous_client(self):
         from google.auth.credentials import AnonymousCredentials
         from google.cloud.storage._http import Connection