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Add log handling and persistent listener

This commit is contained in:
Joshua Boniface 2021-05-30 14:47:39 -04:00
parent a1969eb981
commit ed4f84a3ec
1 changed files with 44 additions and 15 deletions
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59
daemon-common/zkhandler.py
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@ -22,7 +22,7 @@
import time
import uuid
from functools import wraps
from kazoo.client import KazooClient
from kazoo.client import KazooClient, KazooState
#
@ -79,7 +79,7 @@ class ZKConnectionException(Exception):
# Handler class
#
class ZKHandler(object):
def __init__(self, config):
def __init__(self, config, logger=None):
"""
Initialize an instance of the ZKHandler class with config
@ -87,6 +87,7 @@ class ZKHandler(object):
"""
self.encoding = 'utf8'
self.coordinators = config['coordinators']
self.logger = logger
self.zk_conn = KazooClient(hosts=self.coordinators)
#
@ -95,15 +96,43 @@ class ZKHandler(object):
def coordinators(self):
return str(self.coordinators)
def log(self, message, state=''):
if self.logger is not None:
self.logger.out(message, state)
else:
print(message)
#
# State/connection management
#
def connect(self):
def listener(self, state):
if state == KazooState.CONNECTED:
self.log('Connection to Zookeeper started', state='o')
else:
self.log('Connection to Zookeeper lost', state='w')
while True:
time.sleep(0.5)
_zk_conn = KazooClient(hosts=self.coordinators)
try:
_zk_conn.start()
except Exception:
del _zk_conn
continue
self.zk_conn = _zk_conn
self.zk_conn.add_listener(self.listener)
break
def connect(self, persistent=False):
"""
Start the zk_conn object and connect to the cluster
"""
try:
self.zk_conn.start()
if persistent:
self.zk_conn.add_listener(self.listener)
except Exception as e:
raise ZKConnectionException(self, e)
@ -140,14 +169,14 @@ class ZKHandler(object):
Create or update one or more keys' data
"""
if type(kvpairs) is not list:
print("ZKHandler error: Key-value sequence is not a list")
self.log("ZKHandler error: Key-value sequence is not a list", state='e')
return False
transaction = self.zk_conn.transaction()
for kvpair in (kvpairs):
if type(kvpair) is not tuple:
print("ZKHandler error: Key-value pair '{}' is not a tuple".format(kvpair))
self.log("ZKHandler error: Key-value pair '{}' is not a tuple".format(kvpair), state='e')
return False
key = kvpair[0]
@ -172,14 +201,14 @@ class ZKHandler(object):
try:
transaction.check(key, new_version)
except TypeError:
print("ZKHandler error: Key '{}' does not match expected version".format(key))
self.log("ZKHandler error: Key '{}' does not match expected version".format(key), state='e')
return False
try:
transaction.commit()
return True
except Exception as e:
print("ZKHandler error: Failed to commit transaction: {}".format(e))
self.log("ZKHandler error: Failed to commit transaction: {}".format(e), state='e')
return False
def delete(self, key, recursive=True):
@ -202,7 +231,7 @@ class ZKHandler(object):
Rename one or more keys to a new value
"""
if type(kkpairs) is not list:
print("ZKHandler error: Key-key sequence is not a list")
self.log("ZKHandler error: Key-key sequence is not a list", state='e')
return False
transaction = self.zk_conn.transaction()
@ -221,17 +250,17 @@ class ZKHandler(object):
for kkpair in (kkpairs):
if type(kkpair) is not tuple:
print("ZKHandler error: Key-key pair '{}' is not a tuple".format(kkpair))
self.log("ZKHandler error: Key-key pair '{}' is not a tuple".format(kkpair), state='e')
return False
source_key = kkpair[0]
destination_key = kkpair[1]
if not self.exists(source_key):
print("ZKHander error: Source key '{}' does not exist".format(source_key))
self.log("ZKHander error: Source key '{}' does not exist".format(source_key), state='e')
return False
if self.exists(destination_key):
print("ZKHander error: Destination key '{}' already exists".format(destination_key))
self.log("ZKHander error: Destination key '{}' already exists".format(destination_key), state='e')
return False
rename_element(transaction, source_key, destination_key)
@ -240,7 +269,7 @@ class ZKHandler(object):
transaction.commit()
return True
except Exception as e:
print("ZKHandler error: Failed to commit transaction: {}".format(e))
self.log("ZKHandler error: Failed to commit transaction: {}".format(e), state='e')
return False
#
@ -260,7 +289,7 @@ class ZKHandler(object):
break
except Exception as e:
if count > 5:
print("ZKHandler warning: Failed to acquire read lock after 5 tries: {}".format(e))
self.log("ZKHandler warning: Failed to acquire read lock after 5 tries: {}".format(e), state='e')
break
else:
time.sleep(0.5)
@ -283,7 +312,7 @@ class ZKHandler(object):
break
except Exception as e:
if count > 5:
print("ZKHandler warning: Failed to acquire write lock after 5 tries: {}".format(e))
self.log("ZKHandler warning: Failed to acquire write lock after 5 tries: {}".format(e), state='e')
break
else:
time.sleep(0.5)
@ -306,7 +335,7 @@ class ZKHandler(object):
break
except Exception as e:
if count > 5:
print("ZKHandler warning: Failed to acquire exclusive lock after 5 tries: {}".format(e))
self.log("ZKHandler warning: Failed to acquire exclusive lock after 5 tries: {}".format(e), state='e')
break
else:
time.sleep(0.5)