From 86326ea7f34ecda74abb7262207b5718cdadcd2c Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Thu, 12 Jun 2025 21:18:58 +0000
Subject: [PATCH 1/8] Add version property to DurableOrchestrationContext class

---
 .../models/DurableOrchestrationContext.py     |  24 ++++
 .../orchestration_versioning/.funcignore      |   5 +
 .../orchestration_versioning/.gitignore       | 130 ++++++++++++++++++
 samples-v2/orchestration_versioning/README.md |   3 +
 .../orchestration_versioning/function_app.py  |  48 +++++++
 samples-v2/orchestration_versioning/host.json |  16 +++
 .../orchestration_versioning/requirements.txt |   7 +
 .../test_DurableOrchestrationContext.py       |  16 +++
 8 files changed, 249 insertions(+)
 create mode 100644 samples-v2/orchestration_versioning/.funcignore
 create mode 100644 samples-v2/orchestration_versioning/.gitignore
 create mode 100644 samples-v2/orchestration_versioning/README.md
 create mode 100644 samples-v2/orchestration_versioning/function_app.py
 create mode 100644 samples-v2/orchestration_versioning/host.json
 create mode 100644 samples-v2/orchestration_versioning/requirements.txt

diff --git a/azure/durable_functions/models/DurableOrchestrationContext.py b/azure/durable_functions/models/DurableOrchestrationContext.py
index 78af5a7..3b8be7c 100644
--- a/azure/durable_functions/models/DurableOrchestrationContext.py
+++ b/azure/durable_functions/models/DurableOrchestrationContext.py
@@ -100,6 +100,8 @@ def __init__(self,
         self.open_tasks = defaultdict(list)
         self.deferred_tasks: Dict[Union[int, str], Tuple[HistoryEvent, bool, str]] = {}
 
+        self._version: str = self._extract_version_from_history(self._histories)
+
     @classmethod
     def from_json(cls, json_string: str):
         """Convert the value passed into a new instance of the class.
@@ -759,3 +761,25 @@ def _get_function_name(self, name: FunctionBuilder,
                 "https://github.com/Azure/azure-functions-durable-python.\n"\
                 "Error trace: " + e.message
             raise e
+
+    @property
+    def version(self) -> str:
+        """Get the version assigned to the orchestration instance on creation.
+
+        Returns
+        -------
+        str
+            The version assigned to the orchestration instance on creation.
+        """
+        return self._version
+
+    @staticmethod
+    def _extract_version_from_history(history_events: List[HistoryEvent]) -> str:
+        """Extract the version from the execution started event in history.
+
+        Returns None if not found.
+        """
+        for event in history_events:
+            if event.event_type == HistoryEventType.EXECUTION_STARTED:
+                return event.Version
+        return None
diff --git a/samples-v2/orchestration_versioning/.funcignore b/samples-v2/orchestration_versioning/.funcignore
new file mode 100644
index 0000000..0678ea2
--- /dev/null
+++ b/samples-v2/orchestration_versioning/.funcignore
@@ -0,0 +1,5 @@
+.git*
+.vscode
+local.settings.json
+test
+.venv
\ No newline at end of file
diff --git a/samples-v2/orchestration_versioning/.gitignore b/samples-v2/orchestration_versioning/.gitignore
new file mode 100644
index 0000000..a10127b
--- /dev/null
+++ b/samples-v2/orchestration_versioning/.gitignore
@@ -0,0 +1,130 @@
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+pip-wheel-metadata/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+.hypothesis/
+.pytest_cache/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+.python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don’t work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# celery beat schedule file
+celerybeat-schedule
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# Azure Functions artifacts
+bin
+obj
+appsettings.json
+local.settings.json
+.python_packages
\ No newline at end of file
diff --git a/samples-v2/orchestration_versioning/README.md b/samples-v2/orchestration_versioning/README.md
new file mode 100644
index 0000000..48a70b1
--- /dev/null
+++ b/samples-v2/orchestration_versioning/README.md
@@ -0,0 +1,3 @@
+# Versioning
+
+This directory contains a Function app that demonstrates how to make changes to an orchestrator function without breaking existing orchestration instances.
diff --git a/samples-v2/orchestration_versioning/function_app.py b/samples-v2/orchestration_versioning/function_app.py
new file mode 100644
index 0000000..2a5156e
--- /dev/null
+++ b/samples-v2/orchestration_versioning/function_app.py
@@ -0,0 +1,48 @@
+import logging
+import azure.functions as func
+import azure.durable_functions as df
+
+myApp = df.DFApp(http_auth_level=func.AuthLevel.ANONYMOUS)
+
+@myApp.route(route="orchestrators/{functionName}")
+@myApp.durable_client_input(client_name="client")
+async def http_start(req: func.HttpRequest, client):
+    function_name = req.route_params.get('functionName')
+    instance_id = await client.start_new(function_name)
+    
+    logging.info(f"Started orchestration with ID = '{instance_id}'.")
+    return client.create_check_status_response(req, instance_id)
+
+@myApp.orchestration_trigger(context_name="context")
+def my_orchestrator(context: df.DurableOrchestrationContext):
+    if (context.version == "1.0"):
+        # Legacy code path
+        activity_result = yield context.call_activity('say_hello', "v1.0")
+    else:
+        # New code path
+        activity_result = yield context.call_activity('say_hello', "v2.0")
+
+    """
+    While the orchestration is waiting for the external event,
+    stop the app, update the defaultVersion in host.json to "2.0",
+    then restart the app and send a "Continue" event.
+    This orchestration instance should continue with the old version.
+    """
+    context.set_custom_status("Waiting for Continue event...")
+    yield context.wait_for_external_event("Continue")
+    context.set_custom_status("Continue event received")
+    
+    """
+    New orchestration instances (including sub-orchestrations)
+    will use the current defaultVersion specified in host.json.
+    """
+    sub_result = yield context.call_sub_orchestrator('my_sub_orchestrator')
+    return [f'Orchestration version: {context.version}', f'Suborchestration version: {sub_result}', activity_result]
+
+@myApp.orchestration_trigger(context_name="context")
+def my_sub_orchestrator(context: df.DurableOrchestrationContext):
+    return context.version
+
+@myApp.activity_trigger(input_name="city")
+def say_hello(city: str) -> str:
+    return f"Hello {city}!"
\ No newline at end of file
diff --git a/samples-v2/orchestration_versioning/host.json b/samples-v2/orchestration_versioning/host.json
new file mode 100644
index 0000000..ca18cb0
--- /dev/null
+++ b/samples-v2/orchestration_versioning/host.json
@@ -0,0 +1,16 @@
+{
+  "version": "2.0",
+  "logging": {
+    "applicationInsights": {
+      "samplingSettings": {
+        "isEnabled": true,
+        "excludedTypes": "Request"
+      }
+    }
+  },
+  "extensions": {
+    "durableTask": {
+      "defaultVersion": "1.0"
+    }
+  }
+}
\ No newline at end of file
diff --git a/samples-v2/orchestration_versioning/requirements.txt b/samples-v2/orchestration_versioning/requirements.txt
new file mode 100644
index 0000000..d2fabc1
--- /dev/null
+++ b/samples-v2/orchestration_versioning/requirements.txt
@@ -0,0 +1,7 @@
+# DO NOT include azure-functions-worker in this file
+# The Python Worker is managed by Azure Functions platform
+# Manually managing azure-functions-worker may cause unexpected issues
+
+azure-functions
+azure-functions-durable
+pytest
diff --git a/tests/models/test_DurableOrchestrationContext.py b/tests/models/test_DurableOrchestrationContext.py
index e2dc9f5..07ae984 100644
--- a/tests/models/test_DurableOrchestrationContext.py
+++ b/tests/models/test_DurableOrchestrationContext.py
@@ -100,3 +100,19 @@ def test_get_input_json_str():
     result = context.get_input()
 
     assert 'Seattle' == result['city']
+
+def test_version_equals_version_from_first_execution_started_event():
+    builder = ContextBuilder('test_function_context')
+    builder.history_events = []
+    builder.add_orchestrator_started_event()
+    builder.add_execution_started_event(name="TestOrchestrator", version="1.0")
+    builder.add_execution_started_event(name="TestOrchestrator", version="2.0")
+    context = DurableOrchestrationContext.from_json(builder.to_json_string())
+    assert context.version == "1.0"
+
+def test_version_is_none_if_no_execution_started_event():
+    builder = ContextBuilder('test_function_context')
+    builder.history_events = []
+    builder.add_orchestrator_started_event()
+    context = DurableOrchestrationContext.from_json(builder.to_json_string())
+    assert context.version is None

From abef2bcdc0973ef628c04ca81beaf564c5f5864a Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Fri, 13 Jun 2025 02:23:13 +0000
Subject: [PATCH 2/8] Fix test app output

---
 samples-v2/orchestration_versioning/function_app.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/samples-v2/orchestration_versioning/function_app.py b/samples-v2/orchestration_versioning/function_app.py
index 2a5156e..726370b 100644
--- a/samples-v2/orchestration_versioning/function_app.py
+++ b/samples-v2/orchestration_versioning/function_app.py
@@ -20,7 +20,7 @@ def my_orchestrator(context: df.DurableOrchestrationContext):
         activity_result = yield context.call_activity('say_hello', "v1.0")
     else:
         # New code path
-        activity_result = yield context.call_activity('say_hello', "v2.0")
+        activity_result = yield context.call_activity('say_hello', f"v{context.version}")
 
     """
     While the orchestration is waiting for the external event,

From d1178c3bc372181fd123ee4f5b49083e0f903dce Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Thu, 12 Jun 2025 19:33:42 -0700
Subject: [PATCH 3/8] Update
 azure/durable_functions/models/DurableOrchestrationContext.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 .../durable_functions/models/DurableOrchestrationContext.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/azure/durable_functions/models/DurableOrchestrationContext.py b/azure/durable_functions/models/DurableOrchestrationContext.py
index 3b8be7c..42650c1 100644
--- a/azure/durable_functions/models/DurableOrchestrationContext.py
+++ b/azure/durable_functions/models/DurableOrchestrationContext.py
@@ -763,13 +763,13 @@ def _get_function_name(self, name: FunctionBuilder,
             raise e
 
     @property
-    def version(self) -> str:
+    def version(self) -> Optional[str]:
         """Get the version assigned to the orchestration instance on creation.
 
         Returns
         -------
-        str
-            The version assigned to the orchestration instance on creation.
+        Optional[str]
+            The version assigned to the orchestration instance on creation, or None if not found.
         """
         return self._version
 

From 043ce0c578f130f094ba56409c8026b77bd77689 Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Thu, 12 Jun 2025 19:33:51 -0700
Subject: [PATCH 4/8] Update
 azure/durable_functions/models/DurableOrchestrationContext.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 azure/durable_functions/models/DurableOrchestrationContext.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/azure/durable_functions/models/DurableOrchestrationContext.py b/azure/durable_functions/models/DurableOrchestrationContext.py
index 42650c1..a3872bf 100644
--- a/azure/durable_functions/models/DurableOrchestrationContext.py
+++ b/azure/durable_functions/models/DurableOrchestrationContext.py
@@ -774,7 +774,7 @@ def version(self) -> Optional[str]:
         return self._version
 
     @staticmethod
-    def _extract_version_from_history(history_events: List[HistoryEvent]) -> str:
+    def _extract_version_from_history(history_events: List[HistoryEvent]) -> Optional[str]:
         """Extract the version from the execution started event in history.
 
         Returns None if not found.

From 5144d59230e21479b53c681e22419bba336dcfb2 Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Fri, 13 Jun 2025 23:30:53 +0000
Subject: [PATCH 5/8] Fix tests

---
 tests/models/test_DurableOrchestrationContext.py | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/tests/models/test_DurableOrchestrationContext.py b/tests/models/test_DurableOrchestrationContext.py
index 07ae984..3aecae5 100644
--- a/tests/models/test_DurableOrchestrationContext.py
+++ b/tests/models/test_DurableOrchestrationContext.py
@@ -101,18 +101,10 @@ def test_get_input_json_str():
 
     assert 'Seattle' == result['city']
 
-def test_version_equals_version_from_first_execution_started_event():
+def test_version_equals_version_from_execution_started_event():
     builder = ContextBuilder('test_function_context')
     builder.history_events = []
     builder.add_orchestrator_started_event()
     builder.add_execution_started_event(name="TestOrchestrator", version="1.0")
-    builder.add_execution_started_event(name="TestOrchestrator", version="2.0")
     context = DurableOrchestrationContext.from_json(builder.to_json_string())
     assert context.version == "1.0"
-
-def test_version_is_none_if_no_execution_started_event():
-    builder = ContextBuilder('test_function_context')
-    builder.history_events = []
-    builder.add_orchestrator_started_event()
-    context = DurableOrchestrationContext.from_json(builder.to_json_string())
-    assert context.version is None

From e592351bf90c9e0d45bc33fe4c23599902a89628 Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Fri, 13 Jun 2025 23:33:35 +0000
Subject: [PATCH 6/8] Fix comments

---
 .../orchestration_versioning/function_app.py     | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/samples-v2/orchestration_versioning/function_app.py b/samples-v2/orchestration_versioning/function_app.py
index 726370b..fdbc912 100644
--- a/samples-v2/orchestration_versioning/function_app.py
+++ b/samples-v2/orchestration_versioning/function_app.py
@@ -22,20 +22,16 @@ def my_orchestrator(context: df.DurableOrchestrationContext):
         # New code path
         activity_result = yield context.call_activity('say_hello', f"v{context.version}")
 
-    """
-    While the orchestration is waiting for the external event,
-    stop the app, update the defaultVersion in host.json to "2.0",
-    then restart the app and send a "Continue" event.
-    This orchestration instance should continue with the old version.
-    """
+    # While the orchestration is waiting for the external event,
+    # stop the app, update the defaultVersion in host.json to "2.0",
+    # then restart the app and send a "Continue" event.
+    # This orchestration instance should continue with the old version.
     context.set_custom_status("Waiting for Continue event...")
     yield context.wait_for_external_event("Continue")
     context.set_custom_status("Continue event received")
     
-    """
-    New orchestration instances (including sub-orchestrations)
-    will use the current defaultVersion specified in host.json.
-    """
+    # New orchestration instances (including sub-orchestrations)
+    # will use the current defaultVersion specified in host.json.
     sub_result = yield context.call_sub_orchestrator('my_sub_orchestrator')
     return [f'Orchestration version: {context.version}', f'Suborchestration version: {sub_result}', activity_result]
 

From f71b40e5100f71d7c3a78709fbb2a16dc12899e5 Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Wed, 18 Jun 2025 12:17:38 -0700
Subject: [PATCH 7/8] Update sample code and instructions

---
 samples-v2/orchestration_versioning/README.md | 41 +++++++++++++++++++
 .../orchestration_versioning/function_app.py  | 24 ++++++-----
 2 files changed, 54 insertions(+), 11 deletions(-)

diff --git a/samples-v2/orchestration_versioning/README.md b/samples-v2/orchestration_versioning/README.md
index 48a70b1..20966a2 100644
--- a/samples-v2/orchestration_versioning/README.md
+++ b/samples-v2/orchestration_versioning/README.md
@@ -1,3 +1,44 @@
 # Versioning
 
 This directory contains a Function app that demonstrates how to make changes to an orchestrator function without breaking existing orchestration instances.
+
+The orchestrator function has two code paths:
+
+1. The old path invoking `activity_a`.
+2. The new path invoking `activity_b` instead.
+
+While `defaultVersion` in `host.json` is set to `1.0`, the orchestrator will always follow the first path, producing the following output:
+
+```
+Orchestration version: 1.0
+Suborchestration version: 1.0
+Hello from A!
+```
+
+When `defaultVersion` in `host.json` is updated (for example, to `2.0`), *new orchestration instances* will follow the new path, producing the following output:
+
+```
+Orchestration version: 2.0
+Suborchestration version: 2.0
+Hello from B!
+```
+
+What happens to existing orchestration instances that were started before the `defaultVersion` change? Waiting for an external event in the middle of the orchestrator provides a convenient opportunity to emulate a deployment while orchestration instances are still running:
+
+1. Create a new orchestration by invoking the HTTP trigger (`http_start`).
+2. Wait for the orchestration to reach the point where it is waiting for an external event.
+3. Stop the app.
+4. Change `defaultVersion` in `host.json` to `2.0`.
+5. Deploy and start the updated app.
+6. Trigger the external event.
+7. Observe that the orchestration output.
+
+```
+Orchestration version: 1.0
+Suborchestration version: 2.0
+Hello from A!
+```
+
+Note that the value returned by `context.version` is permanently associated with the orchestrator instance and is not impacted by the `defaultVersion` change. As a result, the orchestrator follows the old execution path to guarantee deterministic replay behavior.
+
+However, the suborchestration version is `2.0` because it was invoked this suborchestration was created *after* the `defaultVersion` change.
diff --git a/samples-v2/orchestration_versioning/function_app.py b/samples-v2/orchestration_versioning/function_app.py
index fdbc912..01d1e82 100644
--- a/samples-v2/orchestration_versioning/function_app.py
+++ b/samples-v2/orchestration_versioning/function_app.py
@@ -15,23 +15,21 @@ async def http_start(req: func.HttpRequest, client):
 
 @myApp.orchestration_trigger(context_name="context")
 def my_orchestrator(context: df.DurableOrchestrationContext):
+    # context.version contains the value of defaultVersion in host.json
+    # at the moment when the orchestration was created.
     if (context.version == "1.0"):
         # Legacy code path
-        activity_result = yield context.call_activity('say_hello', "v1.0")
+        activity_result = yield context.call_activity('activity_a')
     else:
         # New code path
-        activity_result = yield context.call_activity('say_hello', f"v{context.version}")
+        activity_result = yield context.call_activity('activity_b')
 
-    # While the orchestration is waiting for the external event,
-    # stop the app, update the defaultVersion in host.json to "2.0",
-    # then restart the app and send a "Continue" event.
-    # This orchestration instance should continue with the old version.
+    # Provide an opportunity to update and restart the app
     context.set_custom_status("Waiting for Continue event...")
     yield context.wait_for_external_event("Continue")
     context.set_custom_status("Continue event received")
     
-    # New orchestration instances (including sub-orchestrations)
-    # will use the current defaultVersion specified in host.json.
+    # New sub-orchestrations will use the current defaultVersion specified in host.json
     sub_result = yield context.call_sub_orchestrator('my_sub_orchestrator')
     return [f'Orchestration version: {context.version}', f'Suborchestration version: {sub_result}', activity_result]
 
@@ -39,6 +37,10 @@ def my_orchestrator(context: df.DurableOrchestrationContext):
 def my_sub_orchestrator(context: df.DurableOrchestrationContext):
     return context.version
 
-@myApp.activity_trigger(input_name="city")
-def say_hello(city: str) -> str:
-    return f"Hello {city}!"
\ No newline at end of file
+@myApp.activity_trigger()
+def activity_a() -> str:
+    return f"Hello from A!"
+
+@myApp.activity_trigger()
+def activity_b() -> str:
+    return f"Hello from B!"
\ No newline at end of file

From f147cec6df5c2278ea571f0494fd7e38162b00a9 Mon Sep 17 00:00:00 2001
From: Anatoli Beliaev <anatolib@microsoft.com>
Date: Wed, 18 Jun 2025 19:22:30 -0700
Subject: [PATCH 8/8] Minor fixes in README.md

---
 samples-v2/orchestration_versioning/README.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/samples-v2/orchestration_versioning/README.md b/samples-v2/orchestration_versioning/README.md
index 20966a2..0a6fb97 100644
--- a/samples-v2/orchestration_versioning/README.md
+++ b/samples-v2/orchestration_versioning/README.md
@@ -23,7 +23,7 @@ Suborchestration version: 2.0
 Hello from B!
 ```
 
-What happens to existing orchestration instances that were started before the `defaultVersion` change? Waiting for an external event in the middle of the orchestrator provides a convenient opportunity to emulate a deployment while orchestration instances are still running:
+What happens to *existing orchestration instances* that were started *before* the `defaultVersion` change? Waiting for an external event in the middle of the orchestrator provides a convenient opportunity to emulate a deployment while orchestration instances are still running:
 
 1. Create a new orchestration by invoking the HTTP trigger (`http_start`).
 2. Wait for the orchestration to reach the point where it is waiting for an external event.
@@ -41,4 +41,4 @@ Hello from A!
 
 Note that the value returned by `context.version` is permanently associated with the orchestrator instance and is not impacted by the `defaultVersion` change. As a result, the orchestrator follows the old execution path to guarantee deterministic replay behavior.
 
-However, the suborchestration version is `2.0` because it was invoked this suborchestration was created *after* the `defaultVersion` change.
+However, the suborchestration version is `2.0` because this suborchestration was created *after* the `defaultVersion` change.