Re-add Orchestrator object/model

Author: andystaples

azure-functions-durable/azure/durable_functions/__init__.py

@@ -7,9 +7,10 @@
 
 from .decorators.durable_app import Blueprint, DFApp
 from .client import DurableFunctionsClient
+from .orchestrator import Orchestrator
 
 # IMPORTANT: DO NOT REMOVE. `azure-functions` relies on the presence and value of this variable
 # for version detection
 version = "2.x"
 
-__all__ = ["Blueprint", "DFApp", "DurableFunctionsClient", "version"]
+__all__ = ["Blueprint", "DFApp", "DurableFunctionsClient", "Orchestrator", "version"]

azure-functions-durable/azure/durable_functions/decorators/durable_app.py

@@ -12,6 +12,7 @@
 from .metadata import OrchestrationTrigger, ActivityTrigger, EntityTrigger, \
     DurableClient
 from ..worker import DurableFunctionsWorker
+from ..orchestrator import Orchestrator
 
 
 class Blueprint(TriggerApi, BindingApi):
@@ -58,10 +59,7 @@ def _configure_orchestrator_callable(self, wrap) -> Callable:
         def decorator(orchestrator_func: task.Orchestrator):
             # Construct an orchestrator based on the end-user code
 
-            def handle(context) -> str:
-                return DurableFunctionsWorker()._execute_orchestrator(orchestrator_func, context)
-
-            handle.orchestrator_function = orchestrator_func  # type: ignore
+            handle = Orchestrator.create(orchestrator_func)
 
             # invoke next decorator, with the Orchestrator as input
             handle.__name__ = orchestrator_func.__name__

azure-functions-durable/azure/durable_functions/orchestrator.py

@@ -0,0 +1,69 @@
+"""Durable Orchestrator.
+
+Responsible for orchestrating the execution of the user defined generator
+function.
+"""
+from typing import Callable, Any, Generator
+
+import azure.functions as func
+
+from durabletask.task import OrchestrationContext
+
+from .worker import DurableFunctionsWorker
+
+class Orchestrator:
+    """Durable Orchestration Class.
+
+    Responsible for orchestrating the execution of the user defined generator
+    function.
+    """
+
+    def __init__(self,
+                 activity_func: Callable[[OrchestrationContext, Any], Generator[Any, Any, Any]]):
+        """Create a new orchestrator for the user defined generator.
+
+        Responsible for orchestrating the execution of the user defined
+        generator function.
+        :param activity_func: Generator function to orchestrate.
+        """
+        self.fn: Callable[[OrchestrationContext, Any], Generator[Any, Any, Any]] = activity_func
+
+    def handle(self, context: OrchestrationContext) -> str:
+        """Handle the orchestration of the user defined generator function.
+
+        Parameters
+        ----------
+        context : DurableOrchestrationContext
+            The DF orchestration context
+
+        Returns
+        -------
+        str
+            The JSON-formatted string representing the user's orchestration
+            state after this invocation
+        """
+        self.durable_context = context
+        return DurableFunctionsWorker()._execute_orchestrator(self.fn, context)
+
+    @classmethod
+    def create(cls, fn: Callable[[OrchestrationContext, Any], Generator[Any, Any, Any]]) \
+            -> Callable[[Any], str]:
+        """Create an instance of the orchestration class.
+
+        Parameters
+        ----------
+        fn: Callable[[DurableOrchestrationContext], Iterator[Any]]
+            Generator function that needs orchestration
+
+        Returns
+        -------
+        Callable[[Any], str]
+            Handle function of the newly created orchestration client
+        """
+
+        def handle(context) -> str:
+            return Orchestrator(fn).handle(context)
+
+        handle.orchestrator_function = fn  # type: ignore
+
+        return handle