131 lines
5.3 KiB
Python
Executable File
131 lines
5.3 KiB
Python
Executable File
#!/usr/bin/env python3
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import argparse
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import asyncio
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import os
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import signal
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import socket
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from kubernetes_asyncio.client.api_client import ApiClient
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from kubernetes_asyncio.client.exceptions import ApiException
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from kubernetes_asyncio import client, config, watch
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PATH_CONFIG = "/var/bind/bind.conf"
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PATH_ZONEFILE = "/var/bind/db.%s"
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class BindSidecar(object):
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def __init__(self, replica=False):
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self.replica = replica
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self.update_task = None
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self.active_zones = set()
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self.secondaries = {}
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async def update_config(self):
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await asyncio.sleep(5)
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master = socket.gethostbyname("bind-primary") if self.replica else None
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with open(PATH_CONFIG + ".part", "w") as fh:
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for zone in self.active_zones:
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path = PATH_ZONEFILE % zone
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if self.replica:
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fh.write("zone \"%s\" { type slave; masters { %s key zone-transfer; }; };\n" % (zone, master))
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else:
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also_notify = ("also-notify { %s };" % (" ".join(["%s;" % j for j in self.secondaries.values()]))) if self.secondaries else ""
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fh.write("zone \"%s\" { type master; notify explicit; file \"%s\"; %s};\n" % (zone, path, also_notify))
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os.rename(PATH_CONFIG + ".part", PATH_CONFIG)
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print("File", PATH_CONFIG, "updated")
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try:
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with open("/var/bind/named.pid") as fh:
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os.kill(int(fh.read()), signal.SIGHUP)
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except FileNotFoundError:
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print("File /var/bind/named.pid not found, assuming Bind not running yet")
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self.update_task = None
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def reschedule_update(self):
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if self.update_task:
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self.update_task.cancel()
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self.update_task = asyncio.create_task(self.update_config())
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async def watch_bind_zones(self, api_instance):
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flt = "codemowers.io", "v1alpha1", "bindzones"
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method = api_instance.list_cluster_custom_object
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w = watch.Watch()
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print("Subscribing to BindZone updates")
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while True:
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try:
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async for event in w.stream(method, *flt):
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if event["type"] == "ADDED":
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zone = event["object"]["metadata"]["name"]
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self.active_zones.add(zone)
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if not self.replica:
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path = PATH_ZONEFILE % zone
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print("Adding zone: %s" % zone)
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if not os.path.exists(path):
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with open(path + ".part", "w") as fh:
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fh.write("@ IN SOA ns1.%(zone)s. hostmaster.%(zone)s. (1 300 300 2592000 300)\n" % locals())
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fh.write(" NS ns1.%(zone)s.\n" % locals())
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fh.write("ns1 A 127.0.0.1\n")
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os.rename(path + ".part", path)
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self.reschedule_update()
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elif event["type"] == "DELETED":
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print("Removing zone: %s" % zone)
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self.active_zones.remove(zone)
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os.unlink(PATH_ZONEFILE % event["object"]["metadata"]["name"])
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self.reschedule_update()
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except ApiException as e:
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if e.status == 410:
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print("BindZone watch expired")
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else:
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raise
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except asyncio.exceptions.TimeoutError:
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pass
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async def watch_bind_replica_pods(self, v1):
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w = watch.Watch()
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print("Subscribing to pod updates")
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while True:
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try:
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async for event in w.stream(v1.list_namespaced_pod, "bind", label_selector="app=bind-secondary"):
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if not event["object"].status.container_statuses:
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continue
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container_id = event["object"].status.container_statuses[0].container_id
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if event["type"] in ("ADDED", "MODIFIED"):
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if event["object"].status.pod_ip:
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self.secondaries[container_id] = event["object"].status.pod_ip
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print("Pod", event["object"].metadata.name, event["type"].lower(), "; current secondaries:", self.secondaries.values())
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self.reschedule_update()
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except ApiException as e:
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if e.status == 410:
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print("Pod watch expired")
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else:
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raise
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except asyncio.exceptions.TimeoutError:
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pass
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self.secondaries = {}
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async def run(self, v1, api_instance):
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tasks = [self.watch_bind_zones(api_instance)]
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if not self.replica:
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tasks.append(self.watch_bind_replica_pods(v1))
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await asyncio.gather(*tasks)
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async def main():
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if os.getenv("KUBECONFIG"):
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await config.load_kube_config()
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else:
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config.load_incluster_config()
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parser = argparse.ArgumentParser()
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parser.add_argument("--replica", action="store_true")
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args = parser.parse_args()
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async with ApiClient() as api:
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v1 = client.CoreV1Api(api)
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api_instance = client.CustomObjectsApi(api)
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await BindSidecar(args.replica).run(v1, api_instance)
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if __name__ == "__main__":
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loop = asyncio.new_event_loop()
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loop.run_until_complete(main())
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loop.close()
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