final concurrency examples

futures/demo_executor_submit.py

@@ -0,0 +1,31 @@
+"""
+Experiments with futures
+"""
+
+from time import sleep, strftime
+from concurrent import futures
+
+def display(*args):
+    print(strftime('[%H:%M:%S]'), end=' ')
+    print(*args)
+
+
+def loiter(n):
+    msg = '{}loiter({}): doing nothing for {}s...'
+    display(msg.format('\t'*n, n, n))
+    sleep(n)
+    msg = '{}loiter({}): done.'
+    display(msg.format('\t'*n, n))
+    return n * 10
+
+
+def demo_submit():
+    executor = futures.ThreadPoolExecutor(3)
+    future_list = [executor.submit(loiter, n) for n in range(5)]
+    display('done?', [future.done() for future in future_list])
+    display('Waiting for results...')
+    for i, result in enumerate(future.result() for future in future_list):
+        display('result[{}]: {}'.format(i, result))
+
+
+demo_submit()