From 755fe64a13860bac2f094596f0f5928c225a20e3 Mon Sep 17 00:00:00 2001
From: GSmithApps <grant.smith@temporal.io>
Date: Mon, 14 Apr 2025 10:24:07 -0500
Subject: [PATCH 1/8] added custom metric sample

---
 .gitignore                       |  2 +
 README.md                        |  1 +
 custom_metric/README.md          | 33 +++++++++++++++
 custom_metric/activity_worker.py | 71 ++++++++++++++++++++++++++++++++
 custom_metric/client.py          | 23 +++++++++++
 custom_metric/workflow_worker.py | 39 ++++++++++++++++++
 6 files changed, 169 insertions(+)
 create mode 100644 custom_metric/README.md
 create mode 100644 custom_metric/activity_worker.py
 create mode 100644 custom_metric/client.py
 create mode 100644 custom_metric/workflow_worker.py

diff --git a/.gitignore b/.gitignore
index 5c5ffffd..41afe5f8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
 .venv
 .idea
 __pycache__
+.vscode
+.DS_Store
diff --git a/README.md b/README.md
index 832e0d1f..5c1941d1 100644
--- a/README.md
+++ b/README.md
@@ -61,6 +61,7 @@ Some examples require extra dependencies. See each sample's directory for specif
 * [context_propagation](context_propagation) - Context propagation through workflows/activities via interceptor.
 * [custom_converter](custom_converter) - Use a custom payload converter to handle custom types.
 * [custom_decorator](custom_decorator) - Custom decorator to auto-heartbeat a long-running activity.
+* [custom_metric](custom_metric) - Custom metric to record the workflow type in the activity schedule to start latency.
 * [dsl](dsl) - DSL workflow that executes steps defined in a YAML file.
 * [encryption](encryption) - Apply end-to-end encryption for all input/output.
 * [gevent_async](gevent_async) - Combine gevent and Temporal.
diff --git a/custom_metric/README.md b/custom_metric/README.md
new file mode 100644
index 00000000..2af67477
--- /dev/null
+++ b/custom_metric/README.md
@@ -0,0 +1,33 @@
+# Custom Metric
+
+1. Run the server with `temporal server start-dev`
+2. Run the client with `uv run custom_metric/client.py`
+3. Run the workflow worker with `uv run custom_metric/workflow_worker.py`
+4. Run the activity worker with `uv run custom_metric/activity_worker.py`
+5. Go to `http://127.0.0.1:9090/metrics` in your browser
+
+You'll get something like the following:
+
+```txt
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="100"} 0
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="500"} 0
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="1000"} 0
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="5000"} 0
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="10000"} 1
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="100000"} 1
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="1000000"} 1
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="+Inf"} 1
+custom_activity_schedule_to_start_latency_sum{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow"} 6336
+custom_activity_schedule_to_start_latency_count{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow"} 1
+...
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="100"} 0
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="500"} 0
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="1000"} 0
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="5000"} 0
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="10000"} 1
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="100000"} 1
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="1000000"} 1
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="+Inf"} 1
+temporal_activity_schedule_to_start_latency_sum{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue"} 6336
+temporal_activity_schedule_to_start_latency_count{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue"} 1
+```
diff --git a/custom_metric/activity_worker.py b/custom_metric/activity_worker.py
new file mode 100644
index 00000000..2d1ffab0
--- /dev/null
+++ b/custom_metric/activity_worker.py
@@ -0,0 +1,71 @@
+import asyncio
+from concurrent.futures import ThreadPoolExecutor
+
+from temporalio import activity
+from temporalio.client import Client
+from temporalio.runtime import PrometheusConfig, Runtime, TelemetryConfig
+from temporalio.worker import (
+    ActivityInboundInterceptor,
+    ExecuteActivityInput,
+    Interceptor,
+    Worker,
+)
+
+
+class SimpleWorkerInterceptor(Interceptor):
+
+    def intercept_activity(
+        self, next: ActivityInboundInterceptor
+    ) -> ActivityInboundInterceptor:
+        return CustomScheduleToStartInterceptor(next)
+
+
+class CustomScheduleToStartInterceptor(ActivityInboundInterceptor):
+
+    async def execute_activity(self, input: ExecuteActivityInput):
+
+        schedule_to_start = (
+            activity.info().started_time
+            - activity.info().current_attempt_scheduled_time
+        )
+        # Could do the original schedule time instead of current attempt
+        # schedule_to_start_second_option = activity.info().started_time - activity.info().scheduled_time
+
+        meter = activity.metric_meter()
+        histogram = meter.create_histogram_timedelta(
+            "custom_activity_schedule_to_start_latency",
+            description="Time between activity scheduling and start",
+            unit="duration",
+        )
+        histogram.record(
+            schedule_to_start, {"workflow_type": activity.info().workflow_type}
+        )
+        return await self.next.execute_activity(input)
+
+
+@activity.defn
+def print_message():
+    print("in the activity")
+
+
+async def main():
+    runtime = Runtime(
+        telemetry=TelemetryConfig(metrics=PrometheusConfig(bind_address="0.0.0.0:9090"))
+    )
+    client = await Client.connect(
+        "localhost:7233",
+        runtime=runtime,
+    )
+    worker = Worker(
+        client,
+        task_queue="custom-metric-task-queue",
+        activities=[print_message],
+        activity_executor=ThreadPoolExecutor(5),
+        interceptors=[SimpleWorkerInterceptor()],
+    )
+
+    await worker.run()
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
diff --git a/custom_metric/client.py b/custom_metric/client.py
new file mode 100644
index 00000000..8b62d1b9
--- /dev/null
+++ b/custom_metric/client.py
@@ -0,0 +1,23 @@
+import asyncio
+import uuid
+
+from temporalio.client import Client
+
+from custom_metric.workflow_worker import ExecuteActivityWorkflow
+
+
+async def main():
+
+    client = await Client.connect(
+        "localhost:7233",
+    )
+
+    await client.start_workflow(
+        ExecuteActivityWorkflow.run,
+        id="execute-activity-workflow-" + str(uuid.uuid4()),
+        task_queue="custom-metric-task-queue",
+    )
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
diff --git a/custom_metric/workflow_worker.py b/custom_metric/workflow_worker.py
new file mode 100644
index 00000000..5fad0fe9
--- /dev/null
+++ b/custom_metric/workflow_worker.py
@@ -0,0 +1,39 @@
+import asyncio
+from datetime import timedelta
+
+from temporalio import workflow
+from temporalio.client import Client
+from temporalio.worker import Worker
+
+with workflow.unsafe.imports_passed_through():
+    from custom_metric.activity_worker import print_message
+
+
+@workflow.defn
+class ExecuteActivityWorkflow:
+
+    @workflow.run
+    async def run(self):
+        await workflow.execute_activity(
+            print_message,
+            start_to_close_timeout=timedelta(seconds=5),
+        )
+        return None
+
+
+async def main():
+
+    client = await Client.connect(
+        "localhost:7233",
+    )
+    worker = Worker(
+        client,
+        task_queue="custom-metric-task-queue",
+        workflows=[ExecuteActivityWorkflow],
+    )
+
+    await worker.run()
+
+
+if __name__ == "__main__":
+    asyncio.run(main())

From e606ed5b8acf49f435895f53e86cbb39b12888cd Mon Sep 17 00:00:00 2001
From: GSmithApps <grant.smith@temporal.io>
Date: Fri, 18 Apr 2025 13:33:21 -0500
Subject: [PATCH 2/8] Responding to code review

---
 custom_metric/README.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/custom_metric/README.md b/custom_metric/README.md
index 2af67477..6e401bc5 100644
--- a/custom_metric/README.md
+++ b/custom_metric/README.md
@@ -1,5 +1,10 @@
 # Custom Metric
 
+This sample deminstrates two things: how to make a custom metric, and how to use an interceptor.
+The custom metric in this sample shows how to make an activity schedule-to-start-latency with a workflow type tag.
+
+Please see the top-level README for prerequisites such as Python, uv, starting the local temporal development server, etc.
+
 1. Run the server with `temporal server start-dev`
 2. Run the client with `uv run custom_metric/client.py`
 3. Run the workflow worker with `uv run custom_metric/workflow_worker.py`

From 70c1c73a8d89a12742a1debba103a04d99182724 Mon Sep 17 00:00:00 2001
From: GSmithApps <grant.smith@temporal.io>
Date: Fri, 18 Apr 2025 14:03:28 -0500
Subject: [PATCH 3/8] responding to code review

---
 custom_metric/README.md                       | 52 +++++++++----------
 custom_metric/client.py                       | 23 --------
 .../{activity_worker.py => worker.py}         | 42 ++++++++++++---
 custom_metric/workflow_worker.py              | 39 --------------
 4 files changed, 59 insertions(+), 97 deletions(-)
 delete mode 100644 custom_metric/client.py
 rename custom_metric/{activity_worker.py => worker.py} (66%)
 delete mode 100644 custom_metric/workflow_worker.py

diff --git a/custom_metric/README.md b/custom_metric/README.md
index 6e401bc5..cc63c743 100644
--- a/custom_metric/README.md
+++ b/custom_metric/README.md
@@ -1,38 +1,36 @@
 # Custom Metric
 
-This sample deminstrates two things: how to make a custom metric, and how to use an interceptor.
-The custom metric in this sample shows how to make an activity schedule-to-start-latency with a workflow type tag.
+This sample deminstrates two things: (1) how to make a custom metric, and (2) how to use an interceptor.
+The custom metric in this sample is an activity schedule-to-start-latency with a workflow type tag.
 
 Please see the top-level README for prerequisites such as Python, uv, starting the local temporal development server, etc.
 
-1. Run the server with `temporal server start-dev`
-2. Run the client with `uv run custom_metric/client.py`
-3. Run the workflow worker with `uv run custom_metric/workflow_worker.py`
-4. Run the activity worker with `uv run custom_metric/activity_worker.py`
-5. Go to `http://127.0.0.1:9090/metrics` in your browser
+1. Run the worker with `uv run custom_metric/worker.py`
+2. Request execution of the workflow with `temporal workflow start --type ExecuteActivityWorkflow --task-queue custom-metric-task-queue`
+3. Go to `http://127.0.0.1:9090/metrics` in your browser
 
 You'll get something like the following:
 
 ```txt
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="100"} 0
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="500"} 0
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="1000"} 0
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="5000"} 0
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="10000"} 1
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="100000"} 1
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="1000000"} 1
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="+Inf"} 1
-custom_activity_schedule_to_start_latency_sum{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow"} 6336
-custom_activity_schedule_to_start_latency_count{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow"} 1
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="100"} 1
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="500"} 1
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="1000"} 1
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="5000"} 2
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="10000"} 2
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="100000"} 2
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="1000000"} 2
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="+Inf"} 2
+custom_activity_schedule_to_start_latency_sum{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow"} 1010
+custom_activity_schedule_to_start_latency_count{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow"} 2
 ...
-temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="100"} 0
-temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="500"} 0
-temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="1000"} 0
-temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="5000"} 0
-temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="10000"} 1
-temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="100000"} 1
-temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="1000000"} 1
-temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="+Inf"} 1
-temporal_activity_schedule_to_start_latency_sum{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue"} 6336
-temporal_activity_schedule_to_start_latency_count{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue"} 1
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="100"} 1
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="500"} 1
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="1000"} 1
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="5000"} 2
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="10000"} 2
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="100000"} 2
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="1000000"} 2
+temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="+Inf"} 2
+temporal_activity_schedule_to_start_latency_sum{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue"} 1010
+temporal_activity_schedule_to_start_latency_count{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue"} 2
 ```
diff --git a/custom_metric/client.py b/custom_metric/client.py
deleted file mode 100644
index 8b62d1b9..00000000
--- a/custom_metric/client.py
+++ /dev/null
@@ -1,23 +0,0 @@
-import asyncio
-import uuid
-
-from temporalio.client import Client
-
-from custom_metric.workflow_worker import ExecuteActivityWorkflow
-
-
-async def main():
-
-    client = await Client.connect(
-        "localhost:7233",
-    )
-
-    await client.start_workflow(
-        ExecuteActivityWorkflow.run,
-        id="execute-activity-workflow-" + str(uuid.uuid4()),
-        task_queue="custom-metric-task-queue",
-    )
-
-
-if __name__ == "__main__":
-    asyncio.run(main())
diff --git a/custom_metric/activity_worker.py b/custom_metric/worker.py
similarity index 66%
rename from custom_metric/activity_worker.py
rename to custom_metric/worker.py
index 2d1ffab0..a51ad487 100644
--- a/custom_metric/activity_worker.py
+++ b/custom_metric/worker.py
@@ -1,7 +1,9 @@
 import asyncio
+import time
 from concurrent.futures import ThreadPoolExecutor
+from datetime import timedelta
 
-from temporalio import activity
+from temporalio import activity, workflow
 from temporalio.client import Client
 from temporalio.runtime import PrometheusConfig, Runtime, TelemetryConfig
 from temporalio.worker import (
@@ -12,6 +14,31 @@
 )
 
 
+@activity.defn
+def print_message():
+    print("In the activity.")
+    time.sleep(1)
+
+
+@workflow.defn
+class ExecuteActivityWorkflow:
+
+    @workflow.run
+    async def run(self):
+        # Request two concurrent activities with only one task slot so
+        # we can see nontrivial schedule to start times.
+        activity1 = workflow.execute_activity(
+            print_message,
+            start_to_close_timeout=timedelta(seconds=5),
+        )
+        activity2 = workflow.execute_activity(
+            print_message,
+            start_to_close_timeout=timedelta(seconds=5),
+        )
+        await asyncio.gather(activity1, activity2)
+        return None
+
+
 class SimpleWorkerInterceptor(Interceptor):
 
     def intercept_activity(
@@ -43,11 +70,6 @@ async def execute_activity(self, input: ExecuteActivityInput):
         return await self.next.execute_activity(input)
 
 
-@activity.defn
-def print_message():
-    print("in the activity")
-
-
 async def main():
     runtime = Runtime(
         telemetry=TelemetryConfig(metrics=PrometheusConfig(bind_address="0.0.0.0:9090"))
@@ -59,9 +81,13 @@ async def main():
     worker = Worker(
         client,
         task_queue="custom-metric-task-queue",
-        activities=[print_message],
-        activity_executor=ThreadPoolExecutor(5),
         interceptors=[SimpleWorkerInterceptor()],
+        workflows=[ExecuteActivityWorkflow],
+        activities=[print_message],
+        # only one activity executor with two concurrently scheduled activities
+        # to force a nontrivial schedule to start times
+        activity_executor=ThreadPoolExecutor(1),
+        max_concurrent_activities=1,
     )
 
     await worker.run()
diff --git a/custom_metric/workflow_worker.py b/custom_metric/workflow_worker.py
deleted file mode 100644
index 5fad0fe9..00000000
--- a/custom_metric/workflow_worker.py
+++ /dev/null
@@ -1,39 +0,0 @@
-import asyncio
-from datetime import timedelta
-
-from temporalio import workflow
-from temporalio.client import Client
-from temporalio.worker import Worker
-
-with workflow.unsafe.imports_passed_through():
-    from custom_metric.activity_worker import print_message
-
-
-@workflow.defn
-class ExecuteActivityWorkflow:
-
-    @workflow.run
-    async def run(self):
-        await workflow.execute_activity(
-            print_message,
-            start_to_close_timeout=timedelta(seconds=5),
-        )
-        return None
-
-
-async def main():
-
-    client = await Client.connect(
-        "localhost:7233",
-    )
-    worker = Worker(
-        client,
-        task_queue="custom-metric-task-queue",
-        workflows=[ExecuteActivityWorkflow],
-    )
-
-    await worker.run()
-
-
-if __name__ == "__main__":
-    asyncio.run(main())

From 95c09a6edb451031bd952bc5e0b4b5da4c4801ae Mon Sep 17 00:00:00 2001
From: GSmithApps <grant.smith@temporal.io>
Date: Fri, 18 Apr 2025 14:27:31 -0500
Subject: [PATCH 4/8] added tests

---
 tests/custom_metric/__init__.py      |  0
 tests/custom_metric/workflow_test.py | 35 ++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 tests/custom_metric/__init__.py
 create mode 100644 tests/custom_metric/workflow_test.py

diff --git a/tests/custom_metric/__init__.py b/tests/custom_metric/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/custom_metric/workflow_test.py b/tests/custom_metric/workflow_test.py
new file mode 100644
index 00000000..39e6322e
--- /dev/null
+++ b/tests/custom_metric/workflow_test.py
@@ -0,0 +1,35 @@
+import uuid
+
+from temporalio import activity
+from temporalio.testing import WorkflowEnvironment
+from temporalio.worker import Worker
+
+from custom_metric.worker import ExecuteActivityWorkflow
+
+_TASK_QUEUE = "custom-metric-task-queue"
+
+activity_counter = 0
+
+
+async def test_sleep_for_days_workflow():
+
+    @activity.defn(name="print_message")
+    async def print_message_mock():
+        global activity_counter
+        activity_counter += 1
+
+    async with await WorkflowEnvironment.start_time_skipping() as env:
+
+        async with Worker(
+            env.client,
+            task_queue=_TASK_QUEUE,
+            workflows=[ExecuteActivityWorkflow],
+            activities=[print_message_mock],
+        ):
+            result = await env.client.execute_workflow(
+                ExecuteActivityWorkflow.run,
+                id=str(uuid.uuid4()),
+                task_queue=_TASK_QUEUE,
+            )
+            assert result is None
+            assert activity_counter == 2

From 16218552c4f9828c174ce3218236d0a74ec837b5 Mon Sep 17 00:00:00 2001
From: GSmithApps <grant.smith@temporal.io>
Date: Mon, 21 Apr 2025 08:32:25 -0500
Subject: [PATCH 5/8] responding to code review

---
 custom_metric/README.md              | 24 ++++++++++----------
 custom_metric/activity.py            |  9 ++++++++
 custom_metric/starter.py             | 23 +++++++++++++++++++
 custom_metric/worker.py              | 34 ++++------------------------
 custom_metric/workflow.py            | 26 +++++++++++++++++++++
 tests/custom_metric/workflow_test.py | 16 ++++++-------
 6 files changed, 82 insertions(+), 50 deletions(-)
 create mode 100644 custom_metric/activity.py
 create mode 100644 custom_metric/starter.py
 create mode 100644 custom_metric/workflow.py

diff --git a/custom_metric/README.md b/custom_metric/README.md
index cc63c743..de1d51d5 100644
--- a/custom_metric/README.md
+++ b/custom_metric/README.md
@@ -3,25 +3,25 @@
 This sample deminstrates two things: (1) how to make a custom metric, and (2) how to use an interceptor.
 The custom metric in this sample is an activity schedule-to-start-latency with a workflow type tag.
 
-Please see the top-level README for prerequisites such as Python, uv, starting the local temporal development server, etc.
+Please see the top-level [README](../README.md) for prerequisites such as Python, uv, starting the local temporal development server, etc. 
 
 1. Run the worker with `uv run custom_metric/worker.py`
-2. Request execution of the workflow with `temporal workflow start --type ExecuteActivityWorkflow --task-queue custom-metric-task-queue`
+2. Request execution of the workflow with `uv run custom_metric/starter.py`
 3. Go to `http://127.0.0.1:9090/metrics` in your browser
 
 You'll get something like the following:
 
 ```txt
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="100"} 1
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="500"} 1
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="1000"} 1
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="5000"} 2
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="10000"} 2
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="100000"} 2
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="1000000"} 2
-custom_activity_schedule_to_start_latency_bucket{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow",le="+Inf"} 2
-custom_activity_schedule_to_start_latency_sum{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow"} 1010
-custom_activity_schedule_to_start_latency_count{activity_type="print_message",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="ExecuteActivityWorkflow"} 2
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_and_sleep",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="StartTwoActivitiesWorkflow",le="100"} 1
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_and_sleep",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="StartTwoActivitiesWorkflow",le="500"} 1
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_and_sleep",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="StartTwoActivitiesWorkflow",le="1000"} 1
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_and_sleep",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="StartTwoActivitiesWorkflow",le="5000"} 2
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_and_sleep",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="StartTwoActivitiesWorkflow",le="10000"} 2
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_and_sleep",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="StartTwoActivitiesWorkflow",le="100000"} 2
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_and_sleep",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="StartTwoActivitiesWorkflow",le="1000000"} 2
+custom_activity_schedule_to_start_latency_bucket{activity_type="print_and_sleep",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="StartTwoActivitiesWorkflow",le="+Inf"} 2
+custom_activity_schedule_to_start_latency_sum{activity_type="print_and_sleep",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="StartTwoActivitiesWorkflow"} 1010
+custom_activity_schedule_to_start_latency_count{activity_type="print_and_sleep",namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",workflow_type="StartTwoActivitiesWorkflow"} 2
 ...
 temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="100"} 1
 temporal_activity_schedule_to_start_latency_bucket{namespace="default",service_name="temporal-core-sdk",task_queue="custom-metric-task-queue",le="500"} 1
diff --git a/custom_metric/activity.py b/custom_metric/activity.py
new file mode 100644
index 00000000..7f2ee116
--- /dev/null
+++ b/custom_metric/activity.py
@@ -0,0 +1,9 @@
+import time
+
+from temporalio import activity
+
+
+@activity.defn
+def print_and_sleep():
+    print("In the activity.")
+    time.sleep(1)
diff --git a/custom_metric/starter.py b/custom_metric/starter.py
new file mode 100644
index 00000000..ded3a626
--- /dev/null
+++ b/custom_metric/starter.py
@@ -0,0 +1,23 @@
+import asyncio
+import uuid
+
+from temporalio.client import Client
+
+from custom_metric.workflow import StartTwoActivitiesWorkflow
+
+
+async def main():
+
+    client = await Client.connect(
+        "localhost:7233",
+    )
+
+    await client.start_workflow(
+        StartTwoActivitiesWorkflow.run,
+        id="execute-activity-workflow-" + str(uuid.uuid4()),
+        task_queue="custom-metric-task-queue",
+    )
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
diff --git a/custom_metric/worker.py b/custom_metric/worker.py
index a51ad487..168a21b3 100644
--- a/custom_metric/worker.py
+++ b/custom_metric/worker.py
@@ -1,9 +1,7 @@
 import asyncio
-import time
 from concurrent.futures import ThreadPoolExecutor
-from datetime import timedelta
 
-from temporalio import activity, workflow
+from temporalio import activity
 from temporalio.client import Client
 from temporalio.runtime import PrometheusConfig, Runtime, TelemetryConfig
 from temporalio.worker import (
@@ -13,30 +11,8 @@
     Worker,
 )
 
-
-@activity.defn
-def print_message():
-    print("In the activity.")
-    time.sleep(1)
-
-
-@workflow.defn
-class ExecuteActivityWorkflow:
-
-    @workflow.run
-    async def run(self):
-        # Request two concurrent activities with only one task slot so
-        # we can see nontrivial schedule to start times.
-        activity1 = workflow.execute_activity(
-            print_message,
-            start_to_close_timeout=timedelta(seconds=5),
-        )
-        activity2 = workflow.execute_activity(
-            print_message,
-            start_to_close_timeout=timedelta(seconds=5),
-        )
-        await asyncio.gather(activity1, activity2)
-        return None
+from custom_metric.activity import print_and_sleep
+from custom_metric.workflow import StartTwoActivitiesWorkflow
 
 
 class SimpleWorkerInterceptor(Interceptor):
@@ -82,8 +58,8 @@ async def main():
         client,
         task_queue="custom-metric-task-queue",
         interceptors=[SimpleWorkerInterceptor()],
-        workflows=[ExecuteActivityWorkflow],
-        activities=[print_message],
+        workflows=[StartTwoActivitiesWorkflow],
+        activities=[print_and_sleep],
         # only one activity executor with two concurrently scheduled activities
         # to force a nontrivial schedule to start times
         activity_executor=ThreadPoolExecutor(1),
diff --git a/custom_metric/workflow.py b/custom_metric/workflow.py
new file mode 100644
index 00000000..bb8bfeb7
--- /dev/null
+++ b/custom_metric/workflow.py
@@ -0,0 +1,26 @@
+import asyncio
+from datetime import timedelta
+
+from temporalio import workflow
+
+with workflow.unsafe.imports_passed_through():
+    from custom_metric.activity import print_and_sleep
+
+
+@workflow.defn
+class StartTwoActivitiesWorkflow:
+
+    @workflow.run
+    async def run(self):
+        # Request two concurrent activities with only one task slot so
+        # we can see nontrivial schedule to start times.
+        activity1 = workflow.execute_activity(
+            print_and_sleep,
+            start_to_close_timeout=timedelta(seconds=5),
+        )
+        activity2 = workflow.execute_activity(
+            print_and_sleep,
+            start_to_close_timeout=timedelta(seconds=5),
+        )
+        await asyncio.gather(activity1, activity2)
+        return None
diff --git a/tests/custom_metric/workflow_test.py b/tests/custom_metric/workflow_test.py
index 39e6322e..c223f077 100644
--- a/tests/custom_metric/workflow_test.py
+++ b/tests/custom_metric/workflow_test.py
@@ -1,33 +1,31 @@
 import uuid
 
 from temporalio import activity
-from temporalio.testing import WorkflowEnvironment
+from temporalio.client import Client
 from temporalio.worker import Worker
 
-from custom_metric.worker import ExecuteActivityWorkflow
+from custom_metric.worker import StartTwoActivitiesWorkflow
 
 _TASK_QUEUE = "custom-metric-task-queue"
 
 activity_counter = 0
 
 
-async def test_sleep_for_days_workflow():
+async def test_custom_metric_workflow(client: Client):
 
     @activity.defn(name="print_message")
     async def print_message_mock():
         global activity_counter
         activity_counter += 1
 
-    async with await WorkflowEnvironment.start_time_skipping() as env:
-
         async with Worker(
-            env.client,
+            client,
             task_queue=_TASK_QUEUE,
-            workflows=[ExecuteActivityWorkflow],
+            workflows=[StartTwoActivitiesWorkflow],
             activities=[print_message_mock],
         ):
-            result = await env.client.execute_workflow(
-                ExecuteActivityWorkflow.run,
+            result = await client.execute_workflow(
+                StartTwoActivitiesWorkflow.run,
                 id=str(uuid.uuid4()),
                 task_queue=_TASK_QUEUE,
             )

From 2ab0cf12ec2afbf156aed049e0797fd6ea5fc1bf Mon Sep 17 00:00:00 2001
From: GSmithApps <grant.smith@temporal.io>
Date: Mon, 21 Apr 2025 08:33:38 -0500
Subject: [PATCH 6/8] ran formatter

---
 custom_metric/worker.py              | 2 --
 custom_metric/workflow.py            | 1 -
 tests/custom_metric/workflow_test.py | 1 -
 3 files changed, 4 deletions(-)

diff --git a/custom_metric/worker.py b/custom_metric/worker.py
index 168a21b3..9ffad207 100644
--- a/custom_metric/worker.py
+++ b/custom_metric/worker.py
@@ -16,7 +16,6 @@
 
 
 class SimpleWorkerInterceptor(Interceptor):
-
     def intercept_activity(
         self, next: ActivityInboundInterceptor
     ) -> ActivityInboundInterceptor:
@@ -24,7 +23,6 @@ def intercept_activity(
 
 
 class CustomScheduleToStartInterceptor(ActivityInboundInterceptor):
-
     async def execute_activity(self, input: ExecuteActivityInput):
 
         schedule_to_start = (
diff --git a/custom_metric/workflow.py b/custom_metric/workflow.py
index bb8bfeb7..cf37823b 100644
--- a/custom_metric/workflow.py
+++ b/custom_metric/workflow.py
@@ -9,7 +9,6 @@
 
 @workflow.defn
 class StartTwoActivitiesWorkflow:
-
     @workflow.run
     async def run(self):
         # Request two concurrent activities with only one task slot so
diff --git a/tests/custom_metric/workflow_test.py b/tests/custom_metric/workflow_test.py
index c223f077..e3027a45 100644
--- a/tests/custom_metric/workflow_test.py
+++ b/tests/custom_metric/workflow_test.py
@@ -12,7 +12,6 @@
 
 
 async def test_custom_metric_workflow(client: Client):
-
     @activity.defn(name="print_message")
     async def print_message_mock():
         global activity_counter

From 3379774975b652a36977ddbf9c1a8b14a6d0c54c Mon Sep 17 00:00:00 2001
From: GSmithApps <grant.smith@temporal.io>
Date: Mon, 21 Apr 2025 08:38:14 -0500
Subject: [PATCH 7/8] fixing lints

---
 custom_metric/__init__.py | 0
 pyproject.toml            | 1 +
 2 files changed, 1 insertion(+)
 create mode 100644 custom_metric/__init__.py

diff --git a/custom_metric/__init__.py b/custom_metric/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/pyproject.toml b/pyproject.toml
index 5fd96a81..e44b34b9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -86,6 +86,7 @@ packages = [
     "context_propagation",
     "custom_converter",
     "custom_decorator",
+    "custom_metric",
     "dsl",
     "encryption",
     "gevent_async",

From 84fdfeef7f2960872164714bfcee21dd990fb003 Mon Sep 17 00:00:00 2001
From: GSmithApps <grant.smith@temporal.io>
Date: Mon, 21 Apr 2025 09:52:18 -0500
Subject: [PATCH 8/8] responding to code review

---
 tests/custom_metric/workflow_test.py | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/tests/custom_metric/workflow_test.py b/tests/custom_metric/workflow_test.py
index e3027a45..4e107b79 100644
--- a/tests/custom_metric/workflow_test.py
+++ b/tests/custom_metric/workflow_test.py
@@ -12,21 +12,21 @@
 
 
 async def test_custom_metric_workflow(client: Client):
-    @activity.defn(name="print_message")
+    @activity.defn(name="print_and_sleep")
     async def print_message_mock():
         global activity_counter
         activity_counter += 1
 
-        async with Worker(
-            client,
+    async with Worker(
+        client,
+        task_queue=_TASK_QUEUE,
+        workflows=[StartTwoActivitiesWorkflow],
+        activities=[print_message_mock],
+    ):
+        result = await client.execute_workflow(
+            StartTwoActivitiesWorkflow.run,
+            id=str(uuid.uuid4()),
             task_queue=_TASK_QUEUE,
-            workflows=[StartTwoActivitiesWorkflow],
-            activities=[print_message_mock],
-        ):
-            result = await client.execute_workflow(
-                StartTwoActivitiesWorkflow.run,
-                id=str(uuid.uuid4()),
-                task_queue=_TASK_QUEUE,
-            )
-            assert result is None
-            assert activity_counter == 2
+        )
+        assert result is None
+        assert activity_counter == 2