Add finalizer to reap clusters when Python exits (#487)

* Release 2022.5.0

* Add finalizer to shutdown experimental KubeCluster

* Add finalizer to reap clusters when Python exits

* Handle async clusters

Author: jacobtomlinson

dask_kubernetes/experimental/kubecluster.py

@@ -1,11 +1,19 @@
+from __future__ import annotations
+
 import asyncio
+import atexit
+from contextlib import suppress
 from enum import Enum
+import time
+from typing import ClassVar
+import weakref
+
 import kubernetes_asyncio as kubernetes
 
-from distributed.core import rpc
+from distributed.core import Status, rpc
 from distributed.deploy import Cluster
 
-from distributed.utils import Log, Logs, LoopRunner
+from distributed.utils import Log, Logs, LoopRunner, TimeoutError
 
 from dask_kubernetes.common.auth import ClusterAuth
 from dask_kubernetes.operator import (
@@ -103,6 +111,8 @@ class KubeCluster(Cluster):
     KubeCluster.from_name
     """
 
+    _instances: ClassVar[weakref.WeakSet[KubeCluster]] = weakref.WeakSet()
+
     def __init__(
         self,
         name,
@@ -133,6 +143,8 @@ def __init__(
         self._loop_runner = LoopRunner(loop=loop, asynchronous=asynchronous)
         self.loop = self._loop_runner.loop
 
+        self._instances.add(self)
+
         super().__init__(asynchronous=asynchronous, **kwargs)
         if not self.asynchronous:
             self._loop_runner.start()
@@ -363,11 +375,11 @@ async def _delete_worker_group(self, name):
                 name=f"{self.name}-cluster-{name}",
             )
 
-    def close(self):
+    def close(self, timeout=3600):
         """Delete the dask cluster"""
-        return self.sync(self._close)
+        return self.sync(self._close, timeout=timeout)
 
-    async def _close(self):
+    async def _close(self, timeout=None):
         await super()._close()
         if self.shutdown_on_close:
             async with kubernetes.client.api_client.ApiClient() as api_client:
@@ -379,7 +391,12 @@ async def _close(self):
                     namespace=self.namespace,
                     name=self.cluster_name,
                 )
+            start = time.time()
             while (await self._get_cluster()) is not None:
+                if time.time() > start + timeout:
+                    raise TimeoutError(
+                        f"Timed out deleting cluster resource {self.cluster_name}"
+                    )
                 await asyncio.sleep(1)
 
     def scale(self, n, worker_group="default"):
@@ -537,3 +554,19 @@ def from_name(cls, name, **kwargs):
         >>> cluster = KubeCluster.from_name(name="simple-cluster")
         """
         return cls(name=name, create_mode=CreateMode.CONNECT_ONLY, **kwargs)
+
+
+@atexit.register
+def reap_clusters():
+    async def _reap_clusters():
+        for cluster in list(KubeCluster._instances):
+            if cluster.shutdown_on_close and cluster.status != Status.closed:
+                await ClusterAuth.load_first(cluster.auth)
+                with suppress(TimeoutError):
+                    if cluster.asynchronous:
+                        await cluster.close(timeout=10)
+                    else:
+                        cluster.close(timeout=10)
+
+    loop = asyncio.get_event_loop()
+    loop.run_until_complete(_reap_clusters())