retry on fail, retry on http status codes

test/web.py

@@ -0,0 +1,24 @@
+from flask import Flask, Response
+import time
+
+app = Flask(__name__)
+
+
+@app.route("/")
+def hello():
+    time.sleep(90)
+    return "Hello World!"
+
+
+@app.route("/500")
+def e500():
+    return Response(status=500)
+
+
+@app.route("/404")
+def e404():
+    return Response(status=404)
+
+
+if __name__ == "__main__":
+    app.run(port=9999)