littlecodersh · October 29, 2016 14:52 · Oct 29, 2016
diff --git a/semaphore-demo.py b/semaphore-demo.py
@@ -0,0 +1,25 @@
+from tornado import httpclient, gen, ioloop, locks
+
+def fetch(urlList, minRequire):
+    l = locks.Semaphore(len(urlList))
+    resultList = []
+
+    @gen.coroutine
+    def _fetch():
+        @gen.coroutine
+        def __fetch(url):
+            r = yield httpclient.AsyncHTTPClient().fetch(url)
+            l.release()
+            resultList.append(r.body)
+            print('Fetched: %s' % url)
+
+        for i in range(len(urlList)): l.acquire()
+        for url in urlList: __fetch(url)
+        for i in range(minRequire): yield l.acquire()
+    ioloop.IOLoop.current().run_sync(_fetch)
+    return resultList
+
+if __name__ == '__main__':
+    urlList = ['http://127.0.0.1:5000/%s' % i for i in range(5)]
+    r = fetch(urlList, 3)
+    print(r)