fix: include original error message in ImportError for LLM client dependencies

Improved import error handling across autogen-ext to include the original
error message, making it easier for users to diagnose dependency issues.

Previously, import errors would show a generic message like:
  'Dependencies for X not found. Please install ...'

Now they show:
  'Dependencies for X not found. Original error: No module named vertexai
   Please install ...'

This helps users distinguish between missing packages and other issues like
version conflicts or missing transitive dependencies.

Files updated:
- models/llama_cpp/__init__.py
- agents/azure/__init__.py
- agents/magentic_one/__init__.py
- runtimes/grpc/__init__.py and worker runtime files
- memory/chromadb/_chromadb.py
- memory/redis/_redis_memory.py
- tools/azure/_ai_search.py

Closes #4605

Author: karthik-idikuda

python/packages/autogen-ext/src/autogen_ext/agents/azure/__init__.py

@@ -2,7 +2,7 @@
     from ._azure_ai_agent import AzureAIAgent
 except ImportError as e:
     raise ImportError(
-        "Dependencies for AzureAIAgent not found. "
+        f"Dependencies for AzureAIAgent not found. Original error: {e}\n"
         'Please install autogen-ext with the "azure" extra: '
         'pip install "autogen-ext[azure]"'
     ) from e

python/packages/autogen-ext/src/autogen_ext/agents/magentic_one/__init__.py

@@ -2,7 +2,7 @@
     from ._magentic_one_coder_agent import MagenticOneCoderAgent
 except ImportError as e:
     raise ImportError(
-        "Dependencies for MagenticOneCoderAgent not found. "
+        f"Dependencies for MagenticOneCoderAgent not found. Original error: {e}\n"
         'Please install autogen-ext with the "magentic-one" extra: '
         'pip install "autogen-ext[magentic-one]"'
     ) from e

python/packages/autogen-ext/src/autogen_ext/memory/chromadb/_chromadb.py

@@ -28,7 +28,8 @@
     from chromadb.api import ClientAPI
 except ImportError as e:
     raise ImportError(
-        "To use the ChromaDBVectorMemory the chromadb extra must be installed. Run `pip install autogen-ext[chromadb]`"
+        f"To use the ChromaDBVectorMemory the chromadb extra must be installed. Original error: {e}\n"
+        "Run `pip install autogen-ext[chromadb]`"
     ) from e
 
 

python/packages/autogen-ext/src/autogen_ext/memory/redis/_redis_memory.py

@@ -15,7 +15,10 @@
     from redisvl.utils.utils import deserialize, serialize
     from redisvl.utils.vectorize import HFTextVectorizer
 except ImportError as e:
-    raise ImportError("To use Redis Memory RedisVL must be installed. Run `pip install autogen-ext[redisvl]`") from e
+    raise ImportError(
+        f"To use Redis Memory RedisVL must be installed. Original error: {e}\n"
+        "Run `pip install autogen-ext[redisvl]`"
+    ) from e
 
 
 class RedisMemoryConfig(BaseModel):

python/packages/autogen-ext/src/autogen_ext/models/llama_cpp/__init__.py

@@ -2,7 +2,7 @@
     from ._llama_cpp_completion_client import LlamaCppChatCompletionClient
 except ImportError as e:
     raise ImportError(
-        "Dependencies for Llama Cpp not found. "
+        f"Dependencies for Llama Cpp not found. Original error: {e}\n"
         "Please install llama-cpp-python: "
         "pip install autogen-ext[llama-cpp]"
     ) from e

python/packages/autogen-ext/src/autogen_ext/runtimes/grpc/__init__.py

@@ -6,7 +6,8 @@
     import grpc  # type: ignore
 except ImportError as e:
     raise ImportError(
-        "To use the GRPC runtime the grpc extra must be installed. Run `pip install autogen-ext[grpc]`"
+        f"To use the GRPC runtime the grpc extra must be installed. Original error: {e}\n"
+        "Run `pip install autogen-ext[grpc]`"
     ) from e
 
 __all__ = [

python/packages/autogen-ext/src/autogen_ext/runtimes/grpc/_worker_runtime.py

@@ -66,7 +66,7 @@
 try:
     import grpc.aio
 except ImportError as e:
-    raise ImportError(GRPC_IMPORT_ERROR_STR) from e
+    raise ImportError(f"{GRPC_IMPORT_ERROR_STR} Original error: {e}") from e
 
 if TYPE_CHECKING:
     from .protos.agent_worker_pb2_grpc import AgentRpcAsyncStub

python/packages/autogen-ext/src/autogen_ext/runtimes/grpc/_worker_runtime_host.py

@@ -10,7 +10,7 @@
 try:
     import grpc
 except ImportError as e:
-    raise ImportError(GRPC_IMPORT_ERROR_STR) from e
+    raise ImportError(f"{GRPC_IMPORT_ERROR_STR} Original error: {e}") from e
 from .protos import agent_worker_pb2_grpc
 
 logger = logging.getLogger("autogen_core")

python/packages/autogen-ext/src/autogen_ext/runtimes/grpc/_worker_runtime_host_servicer.py

@@ -16,7 +16,7 @@
 try:
     import grpc
 except ImportError as e:
-    raise ImportError(GRPC_IMPORT_ERROR_STR) from e
+    raise ImportError(f"{GRPC_IMPORT_ERROR_STR} Original error: {e}") from e
 
 from .protos import agent_worker_pb2, agent_worker_pb2_grpc, cloudevent_pb2
 

python/packages/autogen-ext/src/autogen_ext/tools/azure/_ai_search.py

@@ -154,11 +154,11 @@ async def _get_embedding(self, query: str) -> List[float]:
                 from openai import AsyncAzureOpenAI
 
                 from azure.identity import DefaultAzureCredential
-            except ImportError:
+            except ImportError as e:
                 raise ImportError(
-                    "Azure OpenAI SDK is required for client-side embedding generation. "
+                    f"Azure OpenAI SDK is required for client-side embedding generation. Original error: {e}\n"
                     "Please install it with: uv add openai azure-identity"
-                ) from None
+                ) from e
 
             api_key = getattr(search_config, "openai_api_key", None)
             api_version = getattr(search_config, "openai_api_version", "2023-11-01")
@@ -193,11 +193,11 @@ def get_token() -> str:
         elif embedding_provider.lower() == "openai":
             try:
                 from openai import AsyncOpenAI
-            except ImportError:
+            except ImportError as e:
                 raise ImportError(
-                    "OpenAI SDK is required for client-side embedding generation. "
+                    f"OpenAI SDK is required for client-side embedding generation. Original error: {e}\n"
                     "Please install it with: uv add openai"
-                ) from None
+                ) from e
 
             api_key = getattr(search_config, "openai_api_key", None)
             openai_client = AsyncOpenAI(api_key=api_key)