adding chapter 7 source code

Chapter7/asyncio/asyncio1.py

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+#asyncio1.py to build a basic coroutine
+import asyncio
+import time
+
+
+async def say(delay, msg):
+    await asyncio.sleep(delay)
+    print(msg)
+
+print("Started at ", time.strftime("%X"))
+asyncio.run(say(1,"Good"))
+asyncio.run(say(2, "Morning"))
+print("Stopped at ", time.strftime("%X"))

Chapter7/asyncio/asyncio2.py

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+#asyncio2.py to build and run coroutines in parallel
+import asyncio
+import time
+
+async def say(delay, msg):
+    await asyncio.sleep(delay)
+    print(msg)
+
+async def main ():
+    task1 = asyncio.create_task( say(1, 'Good'))
+    task2 = asyncio.create_task( say(1, 'Morning'))
+    print("Started at ", time.strftime("%X"))
+    await task1
+    await task2
+    print("Stopped at ", time.strftime("%X"))
+
+asyncio.run(main())

Chapter7/asyncio/asyncio3.py

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+#asyncio3.py to distribute work via queue
+import asyncio
+import random
+import time
+
+async def executer(name, queue):
+    while True:
+        exec_time = await queue.get()
+        await asyncio.sleep(exec_time)
+        queue.task_done()
+        print(f'{name} has taken  {exec_time:.2f} seconds')
+
+async def main ():
+
+    myqueue = asyncio.Queue()
+    calc_exuection_time = 0
+    for _ in range(10):
+        sleep_for = random.uniform(0.4, 0.8)
+        calc_exuection_time += sleep_for
+        myqueue.put_nowait(sleep_for)
+
+    tasks = []
+    for id in range(3):
+        task = asyncio.create_task(executer(f'Task-{id+1}', myqueue))
+        tasks.append(task)
+
+    start_time = time.monotonic()
+    await myqueue.join()
+    total_exec_time = time.monotonic() - start_time
+
+    for task in tasks:
+        task.cancel()
+
+    await asyncio.gather(*tasks, return_exceptions=True)
+
+    print(f"Calculated execution time {calc_exuection_time:0.2f}")
+    print(f"Actual execution time {total_exec_time:0.2f}")
+
+asyncio.run(main())

Chapter7/asyncio/asyncio_casestudy.py

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+#asyncio_casestudy.py
+import asyncio
+import time
+
+import aiofiles, aiohttp
+from getfilelistpy import getfilelist
+
+TASK_POOL_SIZE = 10
+
+#update the resource object as per your API key and the gdriver folder id
+resource = {
+    "api_key": "AIzaSyDYKmm85keqnk41DpYa2bxddKrGns4z0",
+    "id": "0B8TxHW2Ci6dbckVweTRlV3RUU",
+    "fields": "files(name,id,webContentLink)",
+}
+
+async def mydownloader(name, queue):
+    while True:
+        # Get the file id and name from the queue
+        item = await queue.get()
+        try:
+            async with aiohttp.ClientSession(connector=aiohttp.TCPConnector(ssl=False)) as session:
+                async with session.get(item['webContentLink']) as resp:
+                    if resp.status == 200:
+                        f = await aiofiles.open('./files/{}'.format(
+                            item['name']), mode='wb')
+                        await f.write(await resp.read())
+                        await f.close()
+        finally:
+            print(f"{name}: Download completed for ",item['name'])
+            queue.task_done()
+
+def get_files(resource):
+    res = getfilelist.GetFileList(resource)
+    files_list = res['fileList'][0]
+    return files_list
+
+async def main ():
+    files = get_files(resource)
+    #add files info into the queue
+    myqueue = asyncio.Queue()
+    for item in files['files']:
+        myqueue.put_nowait(item)
+
+    tasks = []
+    for id in range(TASK_POOL_SIZE):
+        task = asyncio.create_task(
+            mydownloader(f'Task-{id+1}', myqueue))
+        tasks.append(task)
+
+    start_time = time.monotonic()
+    await myqueue.join()
+    total_exec_time = time.monotonic() - start_time
+
+    for task in tasks:
+        task.cancel()
+
+    await asyncio.gather(*tasks, return_exceptions=True)
+
+    print(f'Time taken to download: {total_exec_time:.2f} seconds')
+
+asyncio.run(main())