feature: Add a demo example for PyCon APAC 2023 talk

aiomonitor/monitor.py

@@ -626,7 +626,8 @@ def start_monitor(
         hook_task_factory=hook_task_factory,
         max_termination_history=(
             max_termination_history
-            or get_default_args(monitor_cls.__init__)["max_termination_history"]
+            if max_termination_history is not None
+            else get_default_args(monitor_cls.__init__)["max_termination_history"]
         ),
         locals=locals,
     )

changes/385.feature.md

@@ -0,0 +1 @@
+Add a new demo example to show various features of aiomonitor, especially using the GUI (also for PyCon APAC 2023 talk)

examples/demo.py

@@ -0,0 +1,138 @@
+# NOTE: This example requires Python 3.11 or higher.
+# Use `requirements-dev.txt` to install dependencies.
+
+from __future__ import annotations
+
+import argparse
+import asyncio
+import contextlib
+import enum
+import logging
+import weakref
+
+import uvloop
+from aiohttp import web
+
+import aiomonitor
+from aiomonitor.task import preserve_termination_log
+
+
+class LoopImpl(enum.StrEnum):
+    ASYNCIO = "asyncio"
+    UVLOOP = "uvloop"
+
+
+async def inner2() -> None:
+    await asyncio.sleep(100)
+
+
+async def inner1(tg: asyncio.TaskGroup) -> None:
+    t = tg.create_task(inner2())
+    await t
+
+
+@preserve_termination_log
+async def timer_loop() -> None:
+    async def interval_work():
+        await asyncio.sleep(3.0)
+
+    scope: weakref.WeakSet[asyncio.Task] = weakref.WeakSet()
+    try:
+        while True:
+            await asyncio.sleep(1.0)
+            if len(scope) < 10:
+                t = asyncio.create_task(interval_work(), name="interval-worker")
+                scope.add(t)
+    except asyncio.CancelledError:
+        for t in {*scope}:
+            with contextlib.suppress(asyncio.CancelledError):
+                t.cancel()
+                await t
+
+
+async def simple(request: web.Request) -> web.Response:
+    log = logging.getLogger("demo.aiohttp_server.simple")
+    log.info("Start sleeping")
+    async with asyncio.TaskGroup() as tg:
+        tg.create_task(inner1(tg))
+    log.info("Finished sleeping")
+    return web.Response(text="Simple answer")
+
+
+async def main(
+    *,
+    history_limit: int,
+    num_timers: int,
+) -> None:
+    loop = asyncio.get_running_loop()
+    log_timer_loop = logging.getLogger("demo.timer_loop")
+    log_aiohttp_server = logging.getLogger("demo.aiohttp_server")
+    with aiomonitor.start_monitor(
+        loop,
+        hook_task_factory=True,
+        max_termination_history=history_limit,
+    ):
+        app = web.Application()
+        app.router.add_get("/", simple)
+        timer_loop_tasks = set()
+        for idx in range(num_timers):
+            timer_loop_tasks.add(
+                asyncio.create_task(timer_loop(), name=f"timer-loop-{idx}")
+            )
+            log_timer_loop.info("started a timer loop (%d)", idx)
+        app["timer_loop_tasks"] = timer_loop_tasks
+
+        async def _shutdown_timer_loop_task(app: web.Application) -> None:
+            for idx, t in enumerate(app["timer_loop_tasks"]):
+                log_timer_loop.info("shutting down a timer loop (%d)", idx)
+                t.cancel()
+                await t
+
+        app.on_cleanup.append(_shutdown_timer_loop_task)
+        log_aiohttp_server.info(
+            "started a sample aiohttp server: http://localhost:8090/"
+        )
+        await web._run_app(app, port=8090, host="localhost")
+
+
+if __name__ == "__main__":
+    logging.basicConfig()
+    logging.getLogger("aiomonitor").setLevel(logging.DEBUG)
+    logging.getLogger("demo").setLevel(logging.DEBUG)
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--loop",
+        type=LoopImpl,
+        choices=list(LoopImpl),
+        default=LoopImpl.ASYNCIO,
+        help="The event loop implementation to use [default: asyncio]",
+    )
+    parser.add_argument(
+        "--history-limit",
+        type=int,
+        metavar="COUNT",
+        default=10,
+        help="Set the maximum number of task termination history [default: 10]",
+    )
+    parser.add_argument(
+        "--num-timers",
+        type=int,
+        metavar="COUNT",
+        default=5,
+        help="Set the number of timer loop tasks to demonstrate persistent termination logs [default: 5]",
+    )
+    args = parser.parse_args()
+    match args.loop:
+        case LoopImpl.UVLOOP:
+            uvloop.install()
+        case _:
+            pass
+    try:
+        asyncio.run(
+            main(
+                history_limit=args.history_limit,
+                num_timers=args.num_timers,
+            )
+        )
+    except KeyboardInterrupt:
+        pass