Threading.local的作用

为每个线程创建一个独立的空间，使得线程对自己的空间中的数据进行操作（数据隔离）
代码实现如下

import threading
from threading import local
import time

obj = local()

def task(i):
    obj.xxxxx = i
    time.sleep(2)
    print(obj.xxxxx,i)

for i in range(10):
    t = threading.Thread(target=task,args=(i,))
    t.start()

如何获取一个线程的唯一标记？

可利用threading.get_ident()

import threading

def task(i):
    print(threading.get_ident(),i)

for i in range(10):
    t = threading.Thread(target=task,args=(i,))
    t.start()

运行结果

10060 0
2572 1
4900 2
18088 3
10352 4
1372 5
17796 6
2476 7
14596 8
17488 9

根据字典自定义一个类似于threading.local功能？并可为协程创建独立的空间

import time
import threading
import greenlet

DIC = {}

def task(i):

    # ident = threading.get_ident()
    ident = greenlet.getcurrent()   #获得协程标记
    if ident in DIC:
        DIC[ident]['xxxxx'] = i
    else:
        DIC[ident] = {'xxxxx':i }
    time.sleep(2)

    print(DIC[ident]['xxxxx'],i)

for i in range(10):
    t = threading.Thread(target=task,args=(i,))
    t.start()

将上述代码进行优化，封装到对象中，方便调用

import time
import threading
try:
    import greenlet
    get_ident =  greenlet.getcurrent
except Exception as e:
    get_ident = threading.get_ident

class Local(object):
    DIC = {}

    def __getattr__(self, item):
        ident = get_ident()
        if ident in self.DIC:
            return self.DIC[ident].get(item)
        return None

    def __setattr__(self, key, value):
        ident = get_ident()
        if ident in self.DIC:
            self.DIC[ident][key] = value
        else:
            self.DIC[ident] = {key:value}

obj = Local()

def task(i):
    obj.xxxxx = i
    time.sleep(2)
    print(obj.xxxxx,i)

for i in range(10):
    t = threading.Thread(target=task,args=(i,))
    t.start()