fix: add google-cloud-aiplatform as optional dependency with clear error message (#19437)

- Add google-cloud-aiplatform as optional dependency in pyproject.toml
- Add 'google' extra for easy installation: pip install litellm[google]
- Improve error messages when Google SDK is not installed to guide users

Fixes #5483

litellm/llms/vertex_ai/vertex_llm_base.py

@@ -23,6 +23,11 @@ from .common_utils import (
     is_global_only_vertex_model,
 )
 
+GOOGLE_IMPORT_ERROR_MESSAGE = (
+    "Google Cloud SDK not found. Install it with: pip install 'litellm[google]' "
+    "or pip install google-cloud-aiplatform"
+)
+
 if TYPE_CHECKING:
     from google.auth.credentials import Credentials as GoogleCredentialsObject
 else:
@@ -138,7 +143,10 @@ class VertexBase:
 
     # Google Auth Helpers -- extracted for mocking purposes in tests
     def _credentials_from_identity_pool(self, json_obj, scopes):
-        from google.auth import identity_pool
+        try:
+            from google.auth import identity_pool
+        except ImportError:
+            raise ImportError(GOOGLE_IMPORT_ERROR_MESSAGE)
 
         creds = identity_pool.Credentials.from_info(json_obj)
         if scopes and hasattr(creds, "requires_scopes") and creds.requires_scopes:
@@ -146,7 +154,10 @@ class VertexBase:
         return creds
 
     def _credentials_from_identity_pool_with_aws(self, json_obj, scopes):
-        from google.auth import aws
+        try:
+            from google.auth import aws
+        except ImportError:
+            raise ImportError(GOOGLE_IMPORT_ERROR_MESSAGE)
 
         creds = aws.Credentials.from_info(json_obj)
         if scopes and hasattr(creds, "requires_scopes") and creds.requires_scopes:
@@ -154,22 +165,30 @@ class VertexBase:
         return creds
 
     def _credentials_from_authorized_user(self, json_obj, scopes):
-        import google.oauth2.credentials
+        try:
+            import google.oauth2.credentials
+        except ImportError:
+            raise ImportError(GOOGLE_IMPORT_ERROR_MESSAGE)
 
         return google.oauth2.credentials.Credentials.from_authorized_user_info(
             json_obj, scopes=scopes
         )
 
     def _credentials_from_service_account(self, json_obj, scopes):
-        import google.oauth2.service_account
+        try:
+            import google.oauth2.service_account
+        except ImportError:
+            raise ImportError(GOOGLE_IMPORT_ERROR_MESSAGE)
 
         return google.oauth2.service_account.Credentials.from_service_account_info(
             json_obj, scopes=scopes
         )
 
     def _credentials_from_default_auth(self, scopes):
-
-        import google.auth as google_auth
+        try:
+            import google.auth as google_auth
+        except ImportError:
+            raise ImportError(GOOGLE_IMPORT_ERROR_MESSAGE)
 
         return google_auth.default(scopes=scopes)
 
@@ -261,9 +280,12 @@ class VertexBase:
         return api_base
 
     def refresh_auth(self, credentials: Any) -> None:
-        from google.auth.transport.requests import (
-            Request,  # type: ignore[import-untyped]
-        )
+        try:
+            from google.auth.transport.requests import (
+                Request,  # type: ignore[import-untyped]
+            )
+        except ImportError:
+            raise ImportError(GOOGLE_IMPORT_ERROR_MESSAGE)
 
         credentials.refresh(Request())
 

pyproject.toml

@@ -53,6 +53,7 @@ azure-keyvault-secrets = {version = "^4.8.0", optional = true}
 azure-storage-blob = {version="^12.25.1", optional=true}
 google-cloud-kms = {version = "^2.21.3", optional = true}
 google-cloud-iam = {version = "^2.19.1", optional = true}
+google-cloud-aiplatform = {version = ">=1.38.0", optional = true}
 resend = {version = ">=0.8.0", optional = true}
 pynacl = {version = "^1.5.0", optional = true}
 websockets = {version = "^15.0.1", optional = true}
@@ -126,6 +127,7 @@ semantic-router = ["semantic-router"]
 
 mlflow = ["mlflow"]
 
+google = ["google-cloud-aiplatform"]
 
 [tool.isort]
 profile = "black"