Fix purge requests without a creation start time

CHANGELOG.md

@@ -11,6 +11,10 @@ All notable changes to this project will be documented in this file.
 - Type-hint-driven validation via `df_loads(s, expected_type=...)`: when the V2 programming model provides a return-type annotation for an activity or sub-orchestrator, the annotation is threaded through call sites so the SDK's `df_loads` can validate the deserialized payload against that type (when available). On older `azure-functions` releases the argument is accepted but ignored.
 - Return-type discovery for V2 decorated activities/sub-orchestrators (`azure.durable_functions.models.utils.type_discovery`): resolves the concrete return annotation from the user's registered function, used to supply `expected_type` to `df_loads`.
 
+### Fixed
+
+- `purge_instance_history_by` now supplies the earliest supported creation time when `created_time_from` is omitted, avoiding HTTP 400 responses from the Durable extension.
+
 ## 1.0.0b6
 
 - [Create timer](https://github.com/Azure/azure-functions-durable-python/issues/35) functionality available

azure/durable_functions/models/DurableOrchestrationClient.py

@@ -419,7 +419,8 @@ async def purge_instance_history_by(
         Parameters
         ----------
         created_time_from : Optional[datetime]
-            Delete orchestration history which were created after this Date.
+            Delete orchestration history which were created after this Date. Defaults to the
+            earliest datetime supported by Python.
         created_time_to: Optional[datetime]
             Delete orchestration history which were created before this Date.
         runtime_status: Optional[List[OrchestrationRuntimeStatus]]
@@ -431,6 +432,9 @@ async def purge_instance_history_by(
         PurgeHistoryResult
             The results of the request to purge history
         """
+        if created_time_from is None:
+            created_time_from = datetime.min
+
         options = RpcManagementOptions(created_time_from=created_time_from,
                                        created_time_to=created_time_to,
                                        runtime_status=runtime_status)

azure/durable_functions/models/RpcManagementOptions.py

@@ -37,7 +37,8 @@ def _add_arg(query: List[str], name: str, value: Any):
     @staticmethod
     def _add_date_arg(query: List[str], name: str, value: Optional[datetime]):
         if value:
-            date_as_string = value.strftime(DATETIME_STRING_FORMAT)
+            date_format = DATETIME_STRING_FORMAT.replace("%Y", f"{value.year:04d}", 1)
+            date_as_string = value.strftime(date_format)
             RpcManagementOptions._add_arg(query, name, date_as_string)
 
     def to_url(self, base_url: Optional[str]) -> str:

tests/models/test_DurableOrchestrationClient.py

@@ -351,8 +351,11 @@ async def test_delete_500_purge_instance_history(binding_string):
 
 @pytest.mark.asyncio
 async def test_delete_200_purge_instance_history_by(binding_string):
-    mock_request = MockRequest(expected_url=f"{RPC_BASE_URL}instances/?runtimeStatus=Running",
-                               response=[200, dict(instancesDeleted=1)])
+    mock_request = MockRequest(
+        expected_url=f"{RPC_BASE_URL}instances/"
+                     "?createdTimeFrom=0001-01-01T00:00:00.000000Z"
+                     "&runtimeStatus=Running",
+        response=[200, dict(instancesDeleted=1)])
     client = DurableOrchestrationClient(binding_string)
     client._delete_async_request = mock_request.delete
 
@@ -364,8 +367,11 @@ async def test_delete_200_purge_instance_history_by(binding_string):
 
 @pytest.mark.asyncio
 async def test_delete_404_purge_instance_history_by(binding_string):
-    mock_request = MockRequest(expected_url=f"{RPC_BASE_URL}instances/?runtimeStatus=Running",
-                               response=[404, MESSAGE_404])
+    mock_request = MockRequest(
+        expected_url=f"{RPC_BASE_URL}instances/"
+                     "?createdTimeFrom=0001-01-01T00:00:00.000000Z"
+                     "&runtimeStatus=Running",
+        response=[404, MESSAGE_404])
     client = DurableOrchestrationClient(binding_string)
     client._delete_async_request = mock_request.delete
 
@@ -377,8 +383,11 @@ async def test_delete_404_purge_instance_history_by(binding_string):
 
 @pytest.mark.asyncio
 async def test_delete_500_purge_instance_history_by(binding_string):
-    mock_request = MockRequest(expected_url=f"{RPC_BASE_URL}instances/?runtimeStatus=Running",
-                               response=[500, MESSAGE_500])
+    mock_request = MockRequest(
+        expected_url=f"{RPC_BASE_URL}instances/"
+                     "?createdTimeFrom=0001-01-01T00:00:00.000000Z"
+                     "&runtimeStatus=Running",
+        response=[500, MESSAGE_500])
     client = DurableOrchestrationClient(binding_string)
     client._delete_async_request = mock_request.delete
 

tests/models/test_RpcManagementOptions.py

@@ -77,3 +77,13 @@ def test_datetime_status():
                f"&createdTimeTo={to_as_string}"
 
     assert_urls_match(expected=expected, result=result)
+
+
+def test_min_datetime_status_uses_four_digit_year():
+    options = RpcManagementOptions(created_time_from=datetime.min)
+
+    result = options.to_url(RPC_BASE_URL)
+
+    expected = f"{RPC_BASE_URL}instances/" \
+               "?createdTimeFrom=0001-01-01T00:00:00.000000Z"
+    assert_urls_match(expected=expected, result=result)