[英]global lock causing my program to stop running
每當我運行其中包含threading.Lock
程序的一部分時,我的程序就會完全停止運行(它不會崩潰,只是暫停)。
我需要這個,因為它是一個服務器,多個客戶端可能正在連接並試圖同時覆蓋所有數據。 在運行它時,只有一個線程處於活動狀態,客戶端連接到它。 我也將它用於我的 Sqlite3 數據庫。 我沒有注意到它在那里引起了問題,因為盡管有全局鎖定,它似乎運行得很好。 所有都以相同的格式完成
with global_lock:
這是線程從我導入線程的方式開始的地方
from threading import Thread, Lock
global_lock = Lock()
while True:
conn, addr = s.accept()
connThread = Thread(target=handler, args=(conn, addr))
connThread.daemon = True
connThread.start()
這是程序
def addUser_InHash(username, password):
print("Adding user in hash")
hashID = 0
hashString = username + password
added = False
for i in hashString:
hashID += ord(i)
hashID = hashID % hashKey
print(hashID, "hashID in addUser")
file = open("LoginHashTable.pickle", "rb+")
if os.path.getsize("LoginHashTable.pickle") > 0:
hashTable = pickle.load(file)
print("File not empty,\nSaved Data:\n{}".format(hashTable))
else:
print("File empty")
hashTable = {}
count = 0
while not added:
print("while not count :", count)
count += 1
if hashID in hashTable:
# If this index exists
if hashID > (hashKey - 1):
hashID = 0
else:
hashID += 1
if hashID > (hashKey - 1):
hashID = 0
else:
print("User doesnt exist, adding to hash table")
hashTable[hashID] = [username, password]
print("New Added")
print(hashTable)
added = True
print("Saving updated file addUser_InHash")
if hashTable:
with global_lock:
file.seek(0) # Move file pointer back to beginning of file
file.truncate() # Empty file by truncating to current file pointer position
pickle.dump(hashTable, file)
print(hashTable)
print("Data saved")
file.close()
else:
print("Hash table still empty, addUser_InHash")
def deleteUser_InHash(username, password):
print("In deleteUser_InHash\nUsername: {}\nPassword: {}".format(username,password))
dataFound = True
hashID = 0
count = 0
hashString = username + password
if os.path.getsize("LoginHashTable.pickle") > 0:
file = open("LoginHashTable.pickle", "rb+")
hashTable = pickle.load(file)
print("File not empty,\nSaved Data:\n{}".format(hashTable))
else:
print("File empty")
dataFound = False
if dataFound:
print("datafound true")
for i in hashString:
hashID += ord(i)
hashID = hashID % hashKey
print("hashID:",hashID)
try:
print("In try")
while dataFound:
print("In while, count:",count)
if count == hashKey:
dataFound = False
if hashTable[hashID] == [username,password]:
del hashTable[hashID]
print("Outside global lock")
with global_lock:
print("Inside global lock")
file.seek(0) # Move file pointer back to beginning of file
file.truncate() # Empty file by truncating to current file pointer position
pickle.dump(hashTable, file)
print(hashTable)
print("Data saved")
file.close()
print("Outside global lock")
print("Data updated")
print("User :", username, "deleted")
break
else:
hashID += 1
count += 1
except IndexError:
print("username could not be found")
return False
else:
return False
這兩個函數按以下順序調用:
deleteUser_InHash(username1,password1)
addUser_InHash(username2,password2)
在全球鎖工作正常deleteUser_InHash()
函數,但在停止程序addUser_InHash()
程序掛在這里:
{33: ['foo', 'bar'], 0: ['toni', 'tony'], 34: ['bar', 'foo'], 118: ['fo', 'la'], 8: ['Tom', 'Tom'], 262: ['Kam', 'Kam'], 258: ['yes', 'no']}
Saving updated file addUser_InHash
掛在行上的一段代碼:
if hashTable:
with global_lock:
我知道這是真的,因為它永遠不會進入打印語句:
print(hashTable)
print("Data saved")
在“addUser_InHash()”里面
大家注意:我變了
global_lock = Lock()
到
global_lock = RLock()
現在我的程序運行良好,我相信這與 RLock 允許線程多次重新獲取鎖有關,而普通鎖似乎不能?
來源:https ://docs.python.org/3/library/threading.html#thread-objects
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