new, simpler, cleaner, experimental timeout mechanism

This commit is contained in:
ahmadbilalkhalid 2019-07-25 16:54:06 +05:00
parent 615a070918
commit b198048ed8
1 changed files with 42 additions and 22 deletions

View File

@ -1,9 +1,13 @@
import etcd3 import etcd3
import json import json
import signal import signal
import threading
import time
from dataclasses import dataclass
from collections import namedtuple from collections import namedtuple
from dataclasses import dataclass
from datetime import datetime
from os import path
PseudoEtcdMeta = namedtuple("PseudoEtcdMeta", ["key"]) PseudoEtcdMeta = namedtuple("PseudoEtcdMeta", ["key"])
@ -47,26 +51,42 @@ class Etcd3Wrapper(object):
for entry in r: for entry in r:
yield EtcdEntry(*entry[::-1], value_in_json=value_in_json) yield EtcdEntry(*entry[::-1], value_in_json=value_in_json)
def watch_prefix(self, *args, timeout=0, value_in_json=False, **kwargs): # def watch_prefix(self, *args, timeout=0, value_in_json=False, **kwargs):
# if timeout > 0:
# signal.signal(signal.SIGALRM, raise_timeout)
# while True:
# try:
# if timeout > 0:
# signal.alarm(timeout)
# r, _ = self.client.watch_prefix(*args, **kwargs)
# for event in r:
# signal.alarm(0)
# # if e.value is None don't propagate its value
# if event.value is None:
# continue
# event = EtcdEntry(event, event.value, value_in_json=value_in_json)
# signal.alarm(timeout)
# yield event
# except TimeoutError:
# _value = {"status": "TIMEOUT"}
# yield EtcdEntry(PseudoEtcdMeta(key=b"TIMEOUT"), value=str.encode(json.dumps(_value)))
def watch_prefix(self, key_prefix, timeout=0, value_in_json=False, **kwargs):
r, _ = self.client.watch_prefix(key_prefix, **kwargs)
if timeout > 0: if timeout > 0:
signal.signal(signal.SIGALRM, raise_timeout) t = threading.Thread(target=create_timeout_event,
while True: args=(timeout, key_prefix, self.client))
try: t.start()
if timeout > 0:
signal.alarm(timeout) for event in r:
r, _ = self.client.watch_prefix(*args, **kwargs) if event.value:
event = EtcdEntry(event, event.value, value_in_json=value_in_json)
yield event
for event in r: def create_timeout_event(timeout, key_prefix, etcd_client):
# if e.value is None don't propagate its value while True:
if event.value is None: time.sleep(timeout)
continue _value = {"status": "TIMEOUT", "last_timeout": datetime.utcnow().isoformat()}
event = EtcdEntry(event, event.value, value_in_json=value_in_json) _key = path.join(f"{key_prefix}", "TIMEOUT")
yield event etcd_client.put(_key, _value, value_in_json=True)
except TimeoutError:
_value = {"status": "TIMEOUT"}
yield EtcdEntry(PseudoEtcdMeta(key=b"TIMEOUT"), value=str.encode(json.dumps(_value)))
def raise_timeout(signum, frame):
_ = signum, frame
raise TimeoutError()