#!/usr/bin/env python
# coding: utf-8

# # subprocess.Popen

# In[1]:


get_ipython().run_cell_magic('writefile', 'date1.py', "\nimport subprocess\n\nsubprocess.Popen('date')\n")


# In[2]:


get_ipython().system('python3.4 date1.py')


# In[3]:


get_ipython().run_cell_magic('writefile', 'date2.py', "\nimport subprocess\n\nsubprocess.Popen(['date', '+%H:%M:%S'])\n")


# In[4]:


get_ipython().system('python3.4 date2.py')


# In[5]:


get_ipython().run_cell_magic('writefile', 'date3.py', "\nimport subprocess\n\nsubprocess.Popen('date +%H:%M:%S', shell=True)\n")


# In[6]:


get_ipython().system('python3.4 date3.py')


# In[7]:


get_ipython().run_cell_magic('writefile', 'date4.py', "\nimport subprocess\n\nsubprocess.Popen('date', stdout=subprocess.DEVNULL)\n")


# In[8]:


get_ipython().system('python3.4 date4.py')


# In[9]:


import subprocess

p = subprocess.Popen('cat', stdin=subprocess.PIPE, stdout=subprocess.PIPE)
p.stdin.write(b'Hello!\n')
p.stdin.close()
print(p.poll())
print(p.stdout.read())
print(p.poll())


# # fork

# In[1]:


get_ipython().run_cell_magic('writefile', 'fork.py', "\nimport os\n\npid = os.fork()\nif pid:\n    # parent\n    for _ in range(200):\n        print('hello from parent')\nelse:\n    # child\n    for _ in range(200):\n        print('hello from child')\n")


# In[2]:


get_ipython().system('python3.4 fork.py')


# # threading

# ## def

# In[1]:


get_ipython().run_cell_magic('writefile', 'threads1.py', "\nimport threading\n\ndef action():\n    for _ in range(10):\n        print('hello from', threading.current_thread().name)\n\nfor _ in range(10):\n    thread = threading.Thread(target=action)\n    thread.start()\n")


# In[2]:


get_ipython().system('python3.4 threads1.py')


# ## class

# In[1]:


get_ipython().run_cell_magic('writefile', 'threads2.py', "\nimport threading\n\nclass Worker(threading.Thread):\n    def run(self):\n        for _ in range(10):\n            print('hello from', threading.current_thread().name)\n\nfor _ in range(10):\n    thread = Worker()\n    thread.start()\n")


# In[2]:


get_ipython().system('python3.4 threads2.py')


# ## Неатомарный инкремент в препарированном виде

# In[1]:


import threading
import time

counter = 0

def inc():
    global counter
    v = counter
    time.sleep(0.001)
    counter = v + 1

pool = []
for _ in range(1000):
    th = threading.Thread(target=inc)
    th.start()
    pool.append(th)

for th in pool:
    th.join()

print(counter)


# ## Неатомарный инкремент

# In[1]:


import threading

counter = 0

def inc():
    global counter
    for _ in range(100000):
        counter += 1

pool = []
for _ in range(10):
    th = threading.Thread(target=inc)
    th.start()
    pool.append(th)

for th in pool:
    th.join()

print(counter)


# ## Синхронизация потоков при помощи блокировки

# In[1]:


import threading
import time

counter = 0
lock = threading.Lock()

def inc():
    global counter
    lock.acquire()
    v = counter
    time.sleep(0.001)
    counter = v + 1
    lock.release()

pool = []
for _ in range(1000):
    th = threading.Thread(target=inc)
    th.start()
    pool.append(th)

for th in pool:
    th.join()

print(counter)


# ## Использование with вместе с lock

# In[1]:


import threading
import time

counter = 0
lock = threading.Lock()

def inc():
    global counter
    with lock:
        v = counter
        time.sleep(0.001)
        counter = v + 1

pool = []
for _ in range(1000):
    th = threading.Thread(target=inc)
    th.start()
    pool.append(th)

for th in pool:
    th.join()

print(counter)


# ## Взаимные блокировки, deadlock

# In[3]:


import threading
import time

lock1 = threading.Lock()
lock2 = threading.Lock()

def good():
    with lock1:
        time.sleep(0.001)
        if lock2.acquire(timeout=1):
            print('good')
            lock2.release()
        else:
            print('locking failed :(')

def bad():
    with lock2:
        if lock1.acquire(timeout=1):
            print('bad')
            lock1.release()
        else:
            print('locking failed :(')

threading.Thread(target=good).start()
threading.Thread(target=bad).start()