final concurrency examples

futures/countries/flags_threadpool.py

@@ -1,6 +1,6 @@
 """Download flags of top 20 countries by population
 
-ThreadPool version
+ThreadPoolExecutor version
 
 Sample run::
 
@@ -15,28 +15,29 @@ Sample run::
     20 flags downloaded in 0.93s
 
 """
-
+# BEGIN FLAGS_THREADPOOL
 from concurrent import futures
 
-from flags import save_flag, get_flag, main
+from flags import save_flag, get_flag, show, main  # <1>
 
-MAX_WORKERS = 100
+MAX_WORKERS = 20  # <2>
 
 
-def download_one(cc):
+def download_one(cc):  # <3>
     image = get_flag(cc)
-    print('{} retrieved.'.format(cc.upper()))
+    show(cc)
     save_flag(image, cc.lower() + '.gif')
     return cc
 
 
 def download_many(cc_list):
-    workers = min(len(cc_list), MAX_WORKERS)
-    with futures.ThreadPoolExecutor(workers) as executor:
-        res = executor.map(download_one, sorted(cc_list))
+    workers = min(MAX_WORKERS, len(cc_list))  # <4>
+    with futures.ThreadPoolExecutor(workers) as executor:  # <5>
+        res = executor.map(download_one, sorted(cc_list))  # <6>
 
-    return len(list(res))
+    return len(list(res))  # <7>
 
 
 if __name__ == '__main__':
-    main(download_many)
+    main(download_many)  # <8>
+# END FLAGS_THREADPOOL