From 9f6e8ac503dbb270dc4ee3da2180fe3a8259408e Mon Sep 17 00:00:00 2001
From: Dan Davison <dan.davison@temporal.io>
Date: Fri, 12 Jul 2024 08:19:14 -0400
Subject: [PATCH] reordering commands

---
 dan/reordering-commands.py | 152 +++++++++++++++++++++++++++++++++++++
 1 file changed, 152 insertions(+)
 create mode 100644 dan/reordering-commands.py

diff --git a/dan/reordering-commands.py b/dan/reordering-commands.py
new file mode 100644
index 00000000..c0d67f6b
--- /dev/null
+++ b/dan/reordering-commands.py
@@ -0,0 +1,152 @@
+import asyncio
+
+from temporalio import common, workflow
+from temporalio.client import Client, WorkflowUpdateStage
+from temporalio.exceptions import ApplicationError
+from temporalio.worker import Worker
+
+wid = __file__
+tq = "tq"
+
+
+@workflow.defn
+class MainCoroutineExitShouldHavePriorityOverHandlerWorkflow:
+    def __init__(self) -> None:
+        self.seen_first_signal = False
+        self.seen_second_signal = False
+        self.should_can = True  # a signal could toggle this
+
+    @workflow.run
+    async def run(self):
+        await workflow.wait_condition(
+            lambda: self.seen_first_signal and self.seen_second_signal
+        )
+
+    @workflow.signal
+    async def this_signal_always_executes_first(self):
+        self.seen_first_signal = True
+        if self.should_can:
+            workflow.continue_as_new()
+
+    @workflow.signal
+    async def this_signal_always_executes_second(self):
+        await workflow.wait_condition(lambda: self.seen_first_signal)
+        self.seen_second_signal = True
+        raise ApplicationError("I don't expect this to be raised if signal 1 did CAN")
+
+
+@workflow.defn
+class SecretDetectorWorkflow:
+    def __init__(self) -> None:
+        self.data: list[str] = []
+
+    @workflow.run
+    async def run(self) -> None:
+        await workflow.wait_condition(lambda: False)
+
+    @workflow.signal
+    def send_data(self, data: str):
+        self.data.append(data)
+        self.check_data()
+
+    def check_data(self):
+        for d in self.data:
+            if d.startswith("<SECRET>"):
+                raise ApplicationError("secret detected, shutting down immediately")
+
+    @workflow.update
+    async def read_data(self) -> list[str]:
+        await workflow.wait_condition(lambda: len(self.data) > 0)
+        return self.data
+
+
+@workflow.defn
+class ShutdownImmediatelyWorkflow:
+    def __init__(self) -> None:
+        self.data: list[str] = []
+
+    @workflow.run
+    async def run(self) -> None:
+        await workflow.wait_condition(lambda: False)
+
+    @workflow.signal
+    async def shutdown_immediately(self):
+        self.data.append("immediate shutdown requested")
+        raise ApplicationError("immediate shutdown requested")
+
+    @workflow.update
+    async def read_data(self) -> list[str]:
+        await workflow.wait_condition(lambda: len(self.data) > 0)
+        return self.data
+
+
+async def run_main_coroutine_exit_should_have_priority_over_handler():
+    client = await Client.connect("localhost:7233")
+    async with Worker(
+        client,
+        task_queue=tq,
+        workflows=[MainCoroutineExitShouldHavePriorityOverHandlerWorkflow],
+    ):
+        wf_handle = await client.start_workflow(
+            MainCoroutineExitShouldHavePriorityOverHandlerWorkflow.run,
+            id=wid,
+            task_queue=tq,
+            id_reuse_policy=common.WorkflowIDReusePolicy.TERMINATE_IF_RUNNING,
+        )
+        await wf_handle.signal(
+            MainCoroutineExitShouldHavePriorityOverHandlerWorkflow.this_signal_always_executes_second
+        )
+        await wf_handle.signal(
+            MainCoroutineExitShouldHavePriorityOverHandlerWorkflow.this_signal_always_executes_first
+        )
+
+
+async def run_secret_detector():
+    client = await Client.connect("localhost:7233")
+    async with Worker(
+        client,
+        task_queue=tq,
+        workflows=[SecretDetectorWorkflow],
+    ):
+        wf_handle = await client.start_workflow(
+            SecretDetectorWorkflow.run,
+            id=wid,
+            task_queue=tq,
+            id_reuse_policy=common.WorkflowIDReusePolicy.TERMINATE_IF_RUNNING,
+        )
+
+        upd_handle = await wf_handle.start_update(
+            SecretDetectorWorkflow.read_data,
+            wait_for_stage=WorkflowUpdateStage.ACCEPTED,
+        )
+        await wf_handle.signal(
+            SecretDetectorWorkflow.send_data,
+            "<SECRET> Updates must not return this! </SECRET>",
+        )
+        print(await upd_handle.result())
+
+
+async def run_shutdown_immediately():
+    client = await Client.connect("localhost:7233")
+    async with Worker(
+        client,
+        task_queue=tq,
+        workflows=[ShutdownImmediatelyWorkflow],
+    ):
+        wf_handle = await client.start_workflow(
+            ShutdownImmediatelyWorkflow.run,
+            id=wid,
+            task_queue=tq,
+            id_reuse_policy=common.WorkflowIDReusePolicy.TERMINATE_IF_RUNNING,
+        )
+
+        upd_handle = await wf_handle.start_update(
+            ShutdownImmediatelyWorkflow.read_data,
+            wait_for_stage=WorkflowUpdateStage.ACCEPTED,
+        )
+        await wf_handle.signal(ShutdownImmediatelyWorkflow.shutdown_immediately)
+        print(await upd_handle.result())
+
+
+if __name__ == "__main__":
+    asyncio.run(run_secret_detector())