Question

每当我运行其中包含threading.Lock的程序的一部分时，我的程序就会完全停止运行（它不会崩溃，只是暂停）。

我需要这个，因为它是一台服务器，并且多个客户端可能正在连接并试图同时覆盖所有数据。在运行此程序时，只有一个线程处于活动状态，并且客户端连接到该线程。我也将其用于Sqlite3数据库。我没有注意到它在那引起了问题，因为尽管全局锁定，它似乎运行得很好。所有操作均以相同的格式

with global_lock:

这是线程与我导入线程的方式一起开始的地方

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()

这是程序

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

按以下顺序调用这两个函数：

deleteUser_InHash(username1,password1)
addUser_InHash(username2,password2)

具有全局锁的功能在deleteUser_InHash()函数中正常工作，但在addUser_InHash()中停止程序。

程序挂在这里：

{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

将这段代码挂起：

if hashTable:
    with global_lock:

我知道这是真的，因为它永远不会出现在打印语句中：

print(hashTable)
print("Data saved")

在“ addUser_InHash（）”内部

Answer 1

所有人注意：我更改了

global_lock = Lock()

到

global_lock = RLock()

现在我的程序运行正常，我认为这与RLock允许线程多次重新获取锁，而普通锁似乎不能重新获得锁有关。

来源：https://docs.python.org/3/library/threading.html#thread-objects

全局锁定导致我的程序停止运行

1 个答案: