[App] Fix env variable login

src/lightning_app/CHANGELOG.md

@@ -34,6 +34,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 - Fixed not being able to run multiple lightning apps locally due to port collision ([#15819](https://github.com/Lightning-AI/lightning/pull/15819))
 
+- Fixed a bug where `lightning login` with env variables would not correctly save the credentials ([#16339](https://github.com/Lightning-AI/lightning/pull/16339))
+
 
 ## [1.8.6] - 2022-12-21
 

src/lightning_app/utilities/login.py

@@ -40,20 +40,6 @@ class Auth:
 
     secrets_file = pathlib.Path(LIGHTNING_CREDENTIAL_PATH)
 
-    def __post_init__(self):
-        for key in Keys:
-            setattr(self, key.suffix, os.environ.get(key.value, None))
-
-        self._with_env_var = bool(self.user_id and self.api_key)  # used by authenticate method
-        if self._with_env_var:
-            self.save("", self.user_id, self.api_key, self.user_id)
-            logger.info("Credentials loaded from environment variables")
-        elif self.api_key or self.user_id:
-            raise ValueError(
-                "To use env vars for authentication both "
-                f"{Keys.USER_ID.value} and {Keys.API_KEY.value} should be set."
-            )
-
     def load(self) -> bool:
         """Load credentials from disk and update properties with credentials.
 
@@ -88,13 +74,12 @@ def save(self, token: str = "", user_id: str = "", api_key: str = "", username:
         self.api_key = api_key
         logger.debug("credentials saved successfully")
 
-    @classmethod
-    def clear(cls) -> None:
-        """remove credentials from disk and env variables."""
-        if cls.secrets_file.exists():
-            cls.secrets_file.unlink()
+    def clear(self) -> None:
+        """Remove credentials from disk."""
+        if self.secrets_file.exists():
+            self.secrets_file.unlink()
         for key in Keys:
-            os.environ.pop(key.value, None)
+            setattr(self, key.suffix, None)
         logger.debug("credentials removed successfully")
 
     @property
@@ -119,11 +104,21 @@ def authenticate(self) -> Optional[str]:
         ----------
         authorization header to use when authentication completes.
         """
-        if self._with_env_var:
-            logger.debug("successfully loaded credentials from env")
-            return self.auth_header
-
         if not self.load():
+            # First try to authenticate from env
+            for key in Keys:
+                setattr(self, key.suffix, os.environ.get(key.value, None))
+
+            if self.user_id and self.api_key:
+                self.save("", self.user_id, self.api_key, self.user_id)
+                logger.info("Credentials loaded from environment variables")
+                return self.auth_header
+            elif self.api_key or self.user_id:
+                raise ValueError(
+                    "To use env vars for authentication both "
+                    f"{Keys.USER_ID.value} and {Keys.API_KEY.value} should be set."
+                )
+
             logger.debug("failed to load credentials, opening browser to get new.")
             self._run_server()
             return self.auth_header

tests/tests_app/utilities/test_login.py

@@ -11,7 +11,9 @@
 
 @pytest.fixture(autouse=True)
 def before_each():
-    login.Auth.clear()
+    for key in login.Keys:
+        os.environ.pop(key.value, None)
+    login.Auth().clear()
 
 
 class TestAuthentication:
@@ -25,7 +27,6 @@ def test_can_store_credentials(self):
 
     def test_e2e(self):
         auth = login.Auth()
-        assert auth._with_env_var is False
         auth.save(username="superman", user_id="kr-1234")
         assert auth.secrets_file.exists()
 
@@ -46,6 +47,9 @@ def test_auth_header(self):
         os.environ.setdefault("LIGHTNING_USER_ID", "7c8455e3-7c5f-4697-8a6d-105971d6b9bd")
         os.environ.setdefault("LIGHTNING_API_KEY", "e63fae57-2b50-498b-bc46-d6204cbf330e")
         auth = login.Auth()
+        auth.clear()
+        auth.authenticate()
+
         assert "Basic" in auth.auth_header
         assert (
             auth.auth_header
@@ -57,7 +61,9 @@ def test_authentication_with_invalid_environment_vars():
     # if api key is passed without user id
     os.environ.setdefault("LIGHTNING_API_KEY", "123")
     with pytest.raises(ValueError):
-        login.Auth()
+        auth = login.Auth()
+        auth.clear()
+        auth.authenticate()
 
 
 @mock.patch("lightning_app.utilities.login.AuthServer.login_with_browser")
@@ -66,13 +72,19 @@ def test_authentication_with_environment_vars(browser_login: mock.MagicMock):
     os.environ.setdefault("LIGHTNING_API_KEY", "abc")
 
     auth = login.Auth()
+    auth.clear()
+    auth.authenticate()
+
     assert auth.user_id == "abc"
     assert auth.auth_header == "Basic YWJjOmFiYw=="
-    assert auth._with_env_var is True
     assert auth.authenticate() == auth.auth_header
     # should not run login flow when env vars are passed
     browser_login.assert_not_called()
 
+    # Check credentials file
+    assert auth.secrets_file.exists()
+    assert auth.load() is True
+
 
 def test_get_auth_url():
     auth_url = login.AuthServer().get_auth_url(1234)
@@ -103,13 +115,16 @@ def test_login_with_browser(
 def test_authenticate(click_launch: mock.MagicMock, head: mock.MagicMock, run: mock.MagicMock, port: mock.MagicMock):
     port.return_value = 1234
     auth = login.Auth()
-    auth.user_id = "user_id"
-    auth.api_key = "api_key"
+    auth.clear()
+
+    click_launch.side_effect = lambda _: auth.save("", "user_id", "api_key", "user_id")
+
     auth.authenticate()
     url = f"{LIGHTNING_CLOUD_URL}/sign-in?redirectTo=http%3A%2F%2Flocalhost%3A1234%2Flogin-complete"  # E501
     head.assert_called_with(url)
     click_launch.assert_called_with(url)
     run.assert_called()
+
     assert auth.auth_header == "Basic dXNlcl9pZDphcGlfa2V5"
 
     auth.authenticate()