Upgrade SimpleWebServer to version 2.1.1 (#438)

* Upgrade SimpleWebServer to version 2.1.1

Currently Clipper uses SimpleWebServer([Oct 25, 2016](https://github.com/eidheim/Simple-Web-Server/tree/8e0d3142bfd3c4932d9c7a9b9fcd517b7a4ec05b)) for http serving.
We need to upgrade this module to resolve some bugs and support keep-alive connection.
So we applied all patches except of some to reach [version 2.1.1 (May 27, 2017)](https://github.com/eidheim/Simple-Web-Server/blob/v2.1.1/server_http.hpp).
Diff between SimpleWebServer v2.1.1(left). and SimpleWebServer(right) in this PR is [here](https://www.diffchecker.com/PI1eJFwo).

* applied patch list
  * Nov 7, 2016: [Fixes #82: wrong reset method called in ::start](eidheim/Simple-Web-Server@8da3ad4)
  * Nov 10, 2016: [Fixed crash if server instance gets deleted after the call to io_serv](eidheim/Simple-Web-Server@743785b)
  * Nov 23, 2016: [Fixes #86: can now set timeout on client requests](eidheim/Simple-Web-Server@8a73cb3)
  * Nov 23, 2016: [Minor timeout source cleanups](eidheim/Simple-Web-Server@7d95360)
  * Nov 23: 2016: [Simplified Server::parse_request](eidheim/Simple-Web-Server@0d8052d)
  * Dec 4, 2016: [string::substr comparisons replaced by string::compare](eidheim/Simple-Web-Server@14d848b)
  * Dec 13, 2016: [compile clean with gcc 4.6.3](eidheim/Simple-Web-Server@dc74f77)
  * Dec 19, 2016: [Added client verification when a verify file is passed to Server<HTTP](eidheim/Simple-Web-Server@7a97f82)
  * Dec 19, 2016: [Added error reporting through on_error std::function](eidheim/Simple-Web-Server@eef8a10)
  * Dec 19, 2016: [Minor cleanup](eidheim/Simple-Web-Server@d19244e)
  * Dec 19, 2016: [Minor cleanup](eidheim/Simple-Web-Server@db95a64)
  * Dec 29, 2016: [Cleanup of server-constructors. Previous constructors have been marked](eidheim/Simple-Web-Server@6c3a59d)
  * Dec 29, 2016: [Bugfix for last commit: config.timeout_content now correctly set in old constructor](eidheim/Simple-Web-Server@175d4dd#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * Dec 30, 2016: [Fixed DEPRECATED macro in cases where it is already defined](eidheim/Simple-Web-Server@8c8ef39#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * Dec 31, 2016: [Case insensitive header cleanup. Also cleanup and additions to parse_test](eidheim/Simple-Web-Server@549bc64#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * Jan 1, 2017: [Added on_upgrade for cases where one wants to handle connection upgrades](eidheim/Simple-Web-Server@bfcb325#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * Jan 11, 2017: [Fixed Boost.Regex workaround in regex_orderable. Fixes #100](eidheim/Simple-Web-Server@19627bb#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * Jan 24, 2017: [Possible implementation for fixing #106](eidheim/Simple-Web-Server@600fbe3#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * Jan 24, 2017: [Renamed close_connection_after_send to close_connection_after_response](eidheim/Simple-Web-Server@de560e8#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * Feb 5, 2017: [Added query string parsing and member to request](eidheim/Simple-Web-Server@a4dd2e6#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * Feb 5, 2017: [Travis CI build failed](eidheim/Simple-Web-Server@d554c13#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * Feb 14, 2017: [remove locale dependent stof()](eidheim/Simple-Web-Server@50ce751#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * Feb 27, 2017: [If query string is present then cut it from the reqeust path so find](eidheim/Simple-Web-Server@e585a7a#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * May 6, 2017: [Added support for request header Connection: keep-alive (see #123)](eidheim/Simple-Web-Server@cfafbcb#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * May 27, 2017: [Finished query string parsing implementation (PR #109)](eidheim/Simple-Web-Server@550bbfe#diff-be05a8666afdaf0bcadd9499d09cf33c)
  * May 27, 2017: [Fixed g++ error in Server::Request::parse_query_string](eidheim/Simple-Web-Server@4469de1#diff-be05a8666afdaf0bcadd9499d09cf33c)

* excluded patch list
  * Jan 2, 2017: [Code simplification: got rid of opt_resource at minimal cost](eidheim/Simple-Web-Server@8cdebfb)
  * Jan 2, 2017: [Added warning to Server::resource](eidheim/Simple-Web-Server@fa8c381)
  * Jan 3, 2017: [Removed unnecessary public](eidheim/Simple-Web-Server@f5e65bf)

* Run format_code.sh

* format code

* Run run_unittests.sh

Author: withsmilo

src/frontends/src/query_frontend.hpp

@@ -21,15 +21,15 @@
 
 #include <server_http.hpp>
 
-using clipper::Response;
+using clipper::Feedback;
 using clipper::FeedbackAck;
-using clipper::VersionedModelId;
-using clipper::InputType;
+using clipper::FeedbackQuery;
 using clipper::Input;
+using clipper::InputType;
 using clipper::Output;
 using clipper::Query;
-using clipper::Feedback;
-using clipper::FeedbackQuery;
+using clipper::Response;
+using clipper::VersionedModelId;
 using clipper::json::json_parse_error;
 using clipper::json::json_semantic_error;
 using clipper::redis::labels_to_str;
@@ -120,8 +120,8 @@ class AppMetrics {
 template <class QP>
 class RequestHandler {
  public:
-  RequestHandler(std::string address, int portno, int num_threads)
-      : server_(address, portno, num_threads), query_processor_() {
+  RequestHandler(std::string address, int portno)
+      : server_(address, portno), query_processor_() {
     clipper::Config& conf = clipper::get_config();
     while (!redis_connection_.connect(conf.get_redis_address(),
                                       conf.get_redis_port())) {

src/frontends/src/query_frontend_main.cpp

@@ -26,6 +26,6 @@ int main(int argc, char* argv[]) {
   conf.ready();
 
   query_frontend::RequestHandler<clipper::QueryProcessor> rh(
-      "0.0.0.0", clipper::QUERY_FRONTEND_PORT, 1);
+      "0.0.0.0", clipper::QUERY_FRONTEND_PORT);
   rh.start_listening();
 }

src/frontends/src/query_frontend_tests.cpp

@@ -42,7 +42,7 @@ class QueryFrontendTest : public ::testing::Test {
   std::shared_ptr<redox::Subscriber> subscriber_;
 
   QueryFrontendTest()
-      : rh_("0.0.0.0", 1337, 8),
+      : rh_("0.0.0.0", 1337),
         redis_(std::make_shared<redox::Redox>()),
         subscriber_(std::make_shared<redox::Subscriber>()) {
     Config& conf = get_config();
@@ -348,7 +348,7 @@ TEST_F(QueryFrontendTest, TestReadApplicationsAtStartup) {
   ASSERT_TRUE(add_application(*redis_, name2, input_type2, policy2,
                               default_output2, latency_slo_micros2));
 
-  RequestHandler<MockQueryProcessor> rh2_("127.0.0.1", 1337, 8);
+  RequestHandler<MockQueryProcessor> rh2_("127.0.0.1", 1337);
   size_t two_apps = rh2_.num_applications();
   EXPECT_EQ(two_apps, (size_t)2);
 }
@@ -377,7 +377,7 @@ TEST_F(QueryFrontendTest, TestReadModelsAtStartup) {
   std::unordered_map<std::string, std::string> expected_models = {{"m", "2"},
                                                                   {"n", "3"}};
 
-  RequestHandler<MockQueryProcessor> rh2_("127.0.0.1", 1337, 8);
+  RequestHandler<MockQueryProcessor> rh2_("127.0.0.1", 1337);
   EXPECT_EQ(rh2_.get_current_model_versions(), expected_models);
 }
 
@@ -400,7 +400,7 @@ TEST_F(QueryFrontendTest, TestReadModelLinksAtStartup) {
 
   std::vector<std::string> expected_app1_linked_models = {"m1", "m2", "m3"};
 
-  RequestHandler<MockQueryProcessor> rh2_("127.0.0.1", 1337, 8);
+  RequestHandler<MockQueryProcessor> rh2_("127.0.0.1", 1337);
 
   std::vector<std::string> app1_linked_models =
       rh2_.get_linked_models_for_app(app_name_1);
@@ -424,7 +424,7 @@ TEST_F(QueryFrontendTest, TestReadInvalidModelVersionAtStartup) {
                         container_name, model_path, DEFAULT_BATCH_SIZE));
   // Not setting the version number will cause get_current_model_version()
   // to return -1, and the RequestHandler should then throw a runtime_error.
-  ASSERT_THROW(RequestHandler<QueryProcessor>("127.0.0.1", 1337, 8),
+  ASSERT_THROW(RequestHandler<QueryProcessor>("127.0.0.1", 1337),
                std::runtime_error);
 }