Return an emtpy function context instead of raising

Author: andystaples

azure-functions-durable/azure/durable_functions/internal/compat/function_context.py

@@ -0,0 +1,23 @@
+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT License.
+
+from typing import Any
+
+
+class FunctionContext:
+    """Holds additional function-level attributes not used by Durable.
+
+    Backwards-compatible with the v1 ``FunctionContext``, which was populated
+    from any *extra* fields present in the orchestration-trigger JSON payload
+    beyond those the ``DurableOrchestrationContext`` consumed directly.
+
+    In v2 the orchestration request is a protobuf that carries no such arbitrary
+    extra fields, so this is typically empty -- matching the common v1 case,
+    where the base trigger payload (``instanceId``, ``parentInstanceId``,
+    ``isReplaying``, ``input``, ``upperSchemaVersion``, ``history``) is fully
+    consumed and nothing is left over.
+    """
+
+    def __init__(self, **kwargs: Any) -> None:
+        for key, value in kwargs.items():
+            setattr(self, key, value)

azure-functions-durable/azure/durable_functions/internal/compat/orchestration_context.py

@@ -11,6 +11,7 @@
 from durabletask.task import OrchestrationContext, RetryPolicy, Task
 
 from ..serialization import DEFAULT_FUNCTIONS_DATA_CONVERTER
+from .function_context import FunctionContext
 from .token_source import TokenSource
 
 
@@ -34,6 +35,10 @@ def __init__(self,
         self._input_type = input_type
         self._custom_status: Any = None
         self._will_continue_as_new = False
+        # v1 exposed a FunctionContext bag of any extra trigger-payload fields.
+        # The durabletask protobuf request carries no such extras, so this is
+        # an empty bag -- matching the common v1 runtime case.
+        self._function_context = FunctionContext()
 
     # -- input ---------------------------------------------------------------
     def get_input(self, expected_type: Optional[type] = None) -> Any:
@@ -96,14 +101,16 @@ def parent_instance_id(self) -> Optional[str]:
         return self._ctx.parent_instance_id
 
     @property
-    def function_context(self) -> Any:
-        """Get the Azure Functions-level context.
-
-        Not available: durabletask does not provide the v1 ``FunctionContext``
-        binding metadata.
+    def function_context(self) -> FunctionContext:
+        """Get the Azure Functions-level context (extra trigger-payload fields).
+
+        Returned as an (empty) :class:`FunctionContext` for v1 drop-in
+        compatibility. The durabletask orchestration request does not carry the
+        arbitrary extra fields the v1 JSON trigger payload could, so there is
+        nothing to populate -- which matches the common v1 case where the base
+        payload is fully consumed and the bag is empty.
         """
-        raise NotImplementedError(
-            "function_context is not available in this SDK.")
+        return self._function_context
 
     @property
     def histories(self) -> Any:

tests/azure-functions-durable/test_orchestration_context_compat.py

@@ -142,10 +142,13 @@ def test_parent_instance_id_delegates():
     assert adapter.parent_instance_id == "parent-123"
 
 
-def test_function_context_raises_not_implemented():
+def test_function_context_returns_empty_bag():
+    from azure.durable_functions.internal.compat.function_context import FunctionContext
     adapter, _ = _adapter()
-    with pytest.raises(NotImplementedError):
-        _ = adapter.function_context
+    fc = adapter.function_context
+    assert isinstance(fc, FunctionContext)
+    # Empty by default: no extra attributes, matching the common v1 case.
+    assert [a for a in vars(fc)] == []
 
 
 def test_histories_raises_not_implemented():