feat: proxy worker changes to support the runtime base

workers/proxy_worker/dispatcher.py

@@ -2,6 +2,7 @@
 # Licensed under the MIT License.
 
 import asyncio
+import importlib
 import logging
 import os
 import queue
@@ -11,6 +12,7 @@
 import typing
 from asyncio import AbstractEventLoop
 from dataclasses import dataclass
+from importlib.metadata import entry_points
 from typing import Any, Optional
 
 import grpc
@@ -30,6 +32,7 @@
     check_python_eol
 )
 from proxy_worker.utils.constants import (
+    PYTHON_ENABLE_AGENT_RUNTIME,
     PYTHON_ENABLE_DEBUG_LOGGING,
 )
 from proxy_worker.version import VERSION
@@ -417,7 +420,72 @@ def stop(self) -> None:
 
     @staticmethod
     def reload_library_worker(directory: str):
+        """
+        Load the appropriate runtime using the base package pattern.
+
+        This uses the runtime base package to automatically discover which
+        runtime is loaded.
+
+        If no runtime is registered via the base package, it falls back to
+        the traditional detection method.
+        """
         global _library_worker, _library_worker_has_cv
+
+        if is_envvar_true(PYTHON_ENABLE_AGENT_RUNTIME):
+            # Import base package
+            import azurefunctions.extensions.base as runtime_base
+
+            # Discover all installed runtime packages via entry points
+            available_runtimes = list(entry_points(group='azurefunctions.runtimes'))
+
+            # Only one runtime should be defined
+            if len(available_runtimes) > 1:
+                runtime_names = [ep.name for ep in available_runtimes]
+                raise RuntimeError(
+                    f"Multiple runtimes detected: {runtime_names}. "
+                    f"Only one runtime should be defined."
+                )
+
+            # Load the single runtime entry point if available
+            if available_runtimes:
+                ep = available_runtimes[0]
+                try:
+                    # Load the entry point (triggers import and
+                    # metaclass registration)
+                    ep.load()
+                    logger.debug(f"Loaded runtime entry point: {ep.name}")
+                except Exception as e:
+                    logger.debug(f"Could not load runtime {ep.name}: {e}")
+
+                # Check if a runtime was registered
+                # Check if the runtime base package has the RuntimeFeatureChecker
+                # Check if the runtime is loaded
+                if hasattr(runtime_base, 'RuntimeFeatureChecker') \
+                        and runtime_base.RuntimeFeatureChecker.runtime_loaded():
+                    # Get the registered runtime module
+                    # (e.g., "azure_functions_fastapi.runtime")
+                    runtime_module_name = (
+                        runtime_base.RuntimeTrackerMeta.get_module())
+                    runtime_name = (
+                        runtime_base.RuntimeTrackerMeta.get_runtime_name())
+                    package_name = runtime_base.RuntimeTrackerMeta.get_package_name()
+
+                    logger.debug("Runtime registered: %s (module: %s). "
+                                 "Importing runtime package: %s",
+                                 runtime_name, runtime_module_name, package_name)
+
+                    # Import the top-level runtime package (which exports
+                    # the public API)
+                    runtime_module = importlib.import_module(package_name)
+                    _library_worker = runtime_module
+                    _library_worker_has_cv = _library_worker.invocation_id_cv
+                    # Module has been imported, end check
+                    return
+
+        # No runtime registered via base package
+        # Use traditional detection
+        logger.debug(
+            "No runtime registered via base package, using fallback")
         v2_scriptfile = os.path.join(directory, get_script_file_name())
         if os.path.exists(v2_scriptfile):
             try:

workers/proxy_worker/utils/constants.py

@@ -15,6 +15,8 @@
 PYTHON_SCRIPT_FILE_NAME = "PYTHON_SCRIPT_FILE_NAME"
 PYTHON_SCRIPT_FILE_NAME_DEFAULT = "function_app.py"
 
+PYTHON_ENABLE_AGENT_RUNTIME = "PYTHON_ENABLE_AGENT_RUNTIME"
+
 # EOL Dates
 PYTHON_EOL_DATES = {
     '3.13': '2029-10',