Use workflow.init, refactor

Author: dandavison

message_passing/safe_message_handlers/workflow.py

@@ -65,8 +65,17 @@ class ClusterManagerAssignNodesToJobResult:
 # These updates must run atomically.
 @workflow.defn
 class ClusterManagerWorkflow:
-    def __init__(self) -> None:
-        self.state = ClusterManagerState()
+    @workflow.init
+    def __init__(self, input: ClusterManagerInput) -> None:
+        if input.state:
+            self.state = input.state
+        else:
+            self.state = ClusterManagerState()
+
+        if input.test_continue_as_new:
+            self.max_history_length = 120
+            self.sleep_interval_seconds = 1
+
         # Protects workflow state from interleaved access
         self.nodes_lock = asyncio.Lock()
         self.max_history_length: Optional[int] = None
@@ -202,29 +211,8 @@ async def perform_health_checks(self) -> None:
                     f"Health check failed with error {type(e).__name__}:{e}"
                 )
 
-    # The cluster manager is a long-running "entity" workflow so we need to periodically checkpoint its state and
-    # continue-as-new.
-    def init(self, input: ClusterManagerInput) -> None:
-        if input.state:
-            self.state = input.state
-        if input.test_continue_as_new:
-            self.max_history_length = 120
-            self.sleep_interval_seconds = 1
-
-    def should_continue_as_new(self) -> bool:
-        if workflow.info().is_continue_as_new_suggested():
-            return True
-        # This is just for ease-of-testing.  In production, we trust temporal to tell us when to continue as new.
-        if (
-            self.max_history_length
-            and workflow.info().get_current_history_length() > self.max_history_length
-        ):
-            return True
-        return False
-
     @workflow.run
     async def run(self, input: ClusterManagerInput) -> ClusterManagerResult:
-        self.init(input)
         await workflow.wait_condition(lambda: self.state.cluster_started)
         # Perform health checks at intervals.
         while True:
@@ -239,6 +227,8 @@ async def run(self, input: ClusterManagerInput) -> ClusterManagerResult:
                 pass
             if self.state.cluster_shutdown:
                 break
+            # The cluster manager is a long-running "entity" workflow so we need to periodically checkpoint its state and
+            # continue-as-new.
             if self.should_continue_as_new():
                 # We don't want to leave any job assignment or deletion handlers half-finished when we continue as new.
                 await workflow.wait_condition(lambda: workflow.all_handlers_finished())
@@ -255,3 +245,14 @@ async def run(self, input: ClusterManagerInput) -> ClusterManagerResult:
             len(self.get_assigned_nodes()),
             len(self.get_bad_nodes()),
         )
+
+    def should_continue_as_new(self) -> bool:
+        if workflow.info().is_continue_as_new_suggested():
+            return True
+        # This is just for ease-of-testing.  In production, we trust temporal to tell us when to continue as new.
+        if (
+            self.max_history_length
+            and workflow.info().get_current_history_length() > self.max_history_length
+        ):
+            return True
+        return False