Python Multithreading Queue -

import threading queue import queue

print_lock = threading.lock() def job(worker): print_lock: open('messages.txt') f: line in f: print(line)

def reader(): while true: worker = q.get() job(worker) q.task_done()

q = queue()

for x in range(10): t = threading.thread(target=reader)

t.daemon = true t.start() 

for worker in range(1): q.put(worker)

q.join()

so want each thread reads different messages,

your trying many things learn in same code snippet 1) multi-threading 2) queue data structure 3) thread synchronization mechanisms 4) locking etc.

let me answer regarding multi-threading only.

in case, every thread reading messages because target function "job" opening file , reading data , every thread calling target function.

let me simplify stuff bit.

1. you want read each line of file in new thread. so, instead of opening file in every thread , read it, open file 1 time , put data in list.
2. now, every thread read 1 line list , print it. also, remove printed line list.
3. once, data printed , still thread trying read, add exception.

code :

import threading import sys   #global variable list reading file data global file_data file_data = []  #create lock lock = threading.lock()   def reader():     while len(file_data) != 0:         print threading.currentthread().getname() + " --- "          try:             lock.acquire()             #get 1 line list , print             = file_data.pop()             print          except:             #once data not present, let's print exception message             print "------------------------"             print "no data present in file"             sys.exit()          lock.release()  #read data file , put list open("messages.txt") fh:     file_data = fh.readlines()  x in range(2):     name = "thread_"+str(x)     t = threading.thread(name=name,target=reader)     t.start() 

output:

    c:\users\dinesh\desktop>python demo.py thread_0 --- thread_1 --- each thread read each message  thread_1 --- great   thread_0 --- how ?   thread_1 --- grey   thread_0 --- hey   thread_1 --- dinesh   thread_0 --- hello   ------------------------ no data present in file  c:\users\dinesh\desktop>      c:\users\dinesh\desktop> 

note : know sue of global not recommended. learning purpose good.