Revert "Add locking in common zkhander"

This reverts commit 53c0d2b4f6.

This resulted in a massive performance hit and some inconsistent
behaviour. Revert for now an re-investigate later.

daemon-common/zkhandler.py

@@ -35,33 +35,15 @@ def exists(zk_conn, key):
 
 # Child list function
 def listchildren(zk_conn, key):
-    try:
     children = zk_conn.get_children(key)
     return children
-    except:
-        return None
 
-# Key deletion function
+# Delete key function
 def deletekey(zk_conn, key, recursive=True):
-    lock = exclusivelock(zk_conn, key)
-    lock.acquire()
-
-    try:
     zk_conn.delete(key, recursive=recursive)
-        lock.release()
-        return True
-    except:
-        lock.release()
-        return False
 
 # Rename key recursive function
 def rename_key_element(zk_conn, zk_transaction, source_key, destination_key):
-    lock_source = exclusivelock(zk_conn, source_key)
-    lock_source.acquire()
-
-    lock_destination = exclusivelock(zk_conn, destination_key)
-    lock_destination.acquire()
-
     data_raw = zk_conn.get(source_key)
     data = data_raw[0]
     zk_transaction.create(destination_key, data)
@@ -74,9 +56,6 @@ def rename_key_element(zk_conn, zk_transaction, source_key, destination_key):
 
     zk_transaction.delete(source_key)
 
-    lock_source.release()
-    lock_destination.release()
-
 # Rename key function
 def renamekey(zk_conn, kv):
     # Start up a transaction
@@ -104,18 +83,10 @@ def renamekey(zk_conn, kv):
 
 # Data read function
 def readdata(zk_conn, key):
-    lock = readlock(zk_conn, key)
-    lock.acquire()
-
-    try:
     data_raw = zk_conn.get(key)
     data = data_raw[0].decode('utf8')
     meta = data_raw[1]
-
-        lock.release()
     return data
-    except:
-        return False
 
 # Data write function
 def writedata(zk_conn, kv):
@@ -124,9 +95,6 @@ def writedata(zk_conn, kv):
 
     # Proceed one KV pair at a time
     for key in sorted(kv):
-        lock = writelock(zk_conn, key)
-        lock.acquire()
-
         data = kv[key]
 
         # Check if this key already exists or not
@@ -149,9 +117,7 @@ def writedata(zk_conn, kv):
                 zk_transaction.check(key, new_version)
             except TypeError:
                 print('Zookeeper key "{}" does not match expected version'.format(key))
-                lock.release()
                 return False
-        lock.release()
 
     # Commit the transaction
     try:
@@ -162,48 +128,12 @@ def writedata(zk_conn, kv):
 
 # Write lock function
 def writelock(zk_conn, key):
-    count = 1
-    while True:
-        try:
     lock_id = str(uuid.uuid1())
     lock = zk_conn.WriteLock('{}'.format(key), lock_id)
-            break
-        except Exception:
-            count += 1
-            if count > 5:
-                break
-            else:
-                continue
     return lock
 
 # Read lock function
 def readlock(zk_conn, key):
-    count = 1
-    while True:
-        try:
     lock_id = str(uuid.uuid1())
     lock = zk_conn.ReadLock('{}'.format(key), lock_id)
-            break
-        except Exception:
-            count += 1
-            if count > 5:
-                break
-            else:
-                continue
-    return lock
-
-# Exclusive lock function
-def exclusivelock(zk_conn, key):
-    count = 1
-    while True:
-        try:
-            lock_id = str(uuid.uuid1())
-            lock = zk_conn.Lock('{}'.format(key), lock_id)
-            break
-        except Exception:
-            count += 1
-            if count > 5:
-                break
-            else:
-                continue
     return lock