Python: basic python a2a support (#906)

* basic python a2a support

* fixes

* small fixes

---------

Co-authored-by: Eric Zhu <ekzhu@users.noreply.github.com>

python/packages/main/agent_framework/a2a/__init__.py

@@ -0,0 +1,24 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+import importlib
+from typing import Any
+
+PACKAGE_NAME = "agent_framework_a2a"
+PACKAGE_EXTRA = "a2a"
+_IMPORTS = ["__version__", "A2AAgent"]
+
+
+def __getattr__(name: str) -> Any:
+    if name in _IMPORTS:
+        try:
+            return getattr(importlib.import_module(PACKAGE_NAME), name)
+        except ModuleNotFoundError as exc:
+            raise ModuleNotFoundError(
+                f"The '{PACKAGE_EXTRA}' extra is not installed, "
+                f"please do `pip install agent-framework[{PACKAGE_EXTRA}]`"
+            ) from exc
+    raise AttributeError(f"Module {PACKAGE_NAME} has no attribute {name}.")
+
+
+def __dir__() -> list[str]:
+    return _IMPORTS

python/packages/main/agent_framework/a2a/__init__.pyi

@@ -0,0 +1,5 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+from agent_framework_a2a import A2AAgent, __version__
+
+__all__ = ["A2AAgent", "__version__"]

python/packages/main/pyproject.toml

@@ -35,7 +35,7 @@ dependencies = [
     "opentelemetry-exporter-otlp-proto-grpc>=1.36.0",
     "opentelemetry-semantic-conventions-ai>=0.4.13",
     "aiofiles>=24.1.0",
-    "azure-identity>=1,<2"
+    "azure-identity>=1,<2",
 ]
 
 [project.optional-dependencies]
@@ -63,6 +63,9 @@ runtime = [
 mem0 = [
     "agent-framework-mem0"
 ]
+a2a = [
+    "agent-framework-a2a"
+]
 devui = [
     "agent-framework-devui"
 ]
@@ -71,6 +74,7 @@ all = [
     "agent-framework-azure-ai",
     "agent-framework-runtime",
     "agent-framework-mem0",
+    "agent-framework-a2a",
     "agent-framework-redis",
     "agent-framework-devui",
     "graphviz>=0.20.0"
@@ -91,6 +95,7 @@ fallback-version = "0.0.0"
 testpaths = [
     'tests',
     'packages/main/tests',
+    'packages/a2a/tests',
     'packages/azure-ai/tests',
     'packages/copilotstudio/tests',
     'packages/mem0/tests',