refactor: hide http_server from http api (#610)

include/dsn/dist/replication/meta_service_app.h

@@ -23,16 +23,6 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
-
-/*
- * Description:
- *     What is this file about?
- *
- * Revision history:
- *     xxxx-xx-xx, author, first version
- *     xxxx-xx-xx, author, fix bug about xxx
- */
-
 #pragma once
 
 #include <dsn/cpp/service_app.h>
@@ -51,8 +41,6 @@ class test_checker;
 
 namespace dsn {
 
-class http_server;
-
 namespace service {
 
 class meta_service_app : public service_app
@@ -71,7 +59,6 @@ class meta_service_app : public service_app
 private:
     friend class ::dsn::replication::test::test_checker;
     std::unique_ptr<dsn::replication::meta_service> _service;
-    std::unique_ptr<http_server> _http_server;
     version_http_service *_version_http_service;
 };
 } // namespace service

include/dsn/dist/replication/replication_service_app.h

@@ -40,7 +40,6 @@
 
 namespace dsn {
 
-class http_server;
 class version_http_service;
 
 namespace replication {
@@ -71,7 +70,6 @@ class replication_service_app : public ::dsn::service_app
 private:
     friend class ::dsn::replication::test::test_checker;
     replica_stub_ptr _stub;
-    std::unique_ptr<http_server> _http_server;
     version_http_service *_version_http_service;
 
     static const char *replica_service_app_info(int argc, char **argv);

include/dsn/http/http_server.h

@@ -49,8 +49,6 @@ struct http_response
     http_status_code status_code{http_status_code::ok};
     std::string content_type = "text/plain";
     std::string location;
-
-    message_ptr to_message(message_ex *req) const;
 };
 
 typedef std::function<void(const http_request &req, http_response &resp)> http_callback;
@@ -63,6 +61,9 @@ struct http_call
     http_callback callback;
 };
 
+// A suite of HTTP handlers coupled using the same prefix of the service.
+// If a handler is registered with path 'app/duplication', its real path is
+// "/<root_path>/app/duplication".
 class http_service
 {
 public:
@@ -73,23 +74,12 @@ class http_service
     void register_handler(std::string path, http_callback cb, std::string help);
 };
 
-class http_server : public serverlet<http_server>
-{
-public:
-    explicit http_server();
-
-    ~http_server() override = default;
-
-    void add_service(http_service *service);
-
-    void serve(message_ex *msg);
-
-private:
-    std::map<std::string, std::unique_ptr<http_service>> _service_map;
-};
+// Starts serving HTTP requests.
+// The internal HTTP server will reuse the rDSN server port.
+extern void start_http_server();
 
-/// The rpc code for all the HTTP RPCs.
-/// Since http is used only for system monitoring, it is restricted to lowest priority.
-DEFINE_TASK_CODE_RPC(RPC_HTTP_SERVICE, TASK_PRIORITY_LOW, THREAD_POOL_DEFAULT);
+// NOTE: the memory of `svc` will be transfered to the underlying registry.
+// TODO(wutao): pass `svc` as a std::unique_ptr.
+extern void register_http_service(http_service *svc);
 
 } // namespace dsn

src/http/http_server.cpp

@@ -13,6 +13,7 @@
 #include "perf_counter_http_service.h"
 #include "uri_decoder.h"
 #include "http_call_registry.h"
+#include "http_server_impl.h"
 
 namespace dsn {
 
@@ -63,13 +64,13 @@ http_server::http_server() : serverlet<http_server>("http_server")
     tools::register_message_header_parser<http_message_parser>(NET_HDR_HTTP, {"GET ", "POST"});
 
     // add builtin services
-    add_service(new root_http_service());
+    register_http_service(new root_http_service());
 
 #ifdef DSN_ENABLE_GPERF
-    add_service(new pprof_http_service());
+    register_http_service(new pprof_http_service());
 #endif // DSN_ENABLE_GPERF
 
-    add_service(new perf_counter_http_service());
+    register_http_service(new perf_counter_http_service());
 }
 
 void http_server::serve(message_ex *msg)
@@ -90,14 +91,7 @@ void http_server::serve(message_ex *msg)
         }
     }
 
-    message_ptr resp_msg = resp.to_message(msg);
-    dsn_rpc_reply(resp_msg.get());
-}
-
-void http_server::add_service(http_service *service)
-{
-    dassert(service != nullptr, "");
-    _service_map.emplace(service->path(), std::unique_ptr<http_service>(service));
+    http_response_reply(resp, msg);
 }
 
 /*static*/ error_with<http_request> http_request::parse(message_ex *m)
@@ -178,25 +172,41 @@ void http_server::add_service(http_service *service)
     return ret;
 }
 
-message_ptr http_response::to_message(message_ex *req) const
+/*extern*/ void http_response_reply(const http_response &resp, message_ex *req)
 {
-    message_ptr resp = req->create_response();
+    message_ptr resp_msg = req->create_response();
 
     std::ostringstream os;
-    os << "HTTP/1.1 " << http_status_code_to_string(status_code) << "\r\n";
-    os << "Content-Type: " << content_type << "\r\n";
-    os << "Content-Length: " << body.length() << "\r\n";
-    if (!location.empty()) {
-        os << "Location: " << location << "\r\n";
+    os << "HTTP/1.1 " << http_status_code_to_string(resp.status_code) << "\r\n";
+    os << "Content-Type: " << resp.content_type << "\r\n";
+    os << "Content-Length: " << resp.body.length() << "\r\n";
+    if (!resp.location.empty()) {
+        os << "Location: " << resp.location << "\r\n";
     }
     os << "\r\n";
-    os << body;
+    os << resp.body;
 
-    rpc_write_stream writer(resp.get());
+    rpc_write_stream writer(resp_msg.get());
     writer.write(os.str().data(), os.str().length());
     writer.flush();
 
-    return resp;
+    dsn_rpc_reply(resp_msg.get());
+}
+
+/*extern*/ void start_http_server()
+{
+    // starts http server as a singleton
+    static http_server server;
+}
+
+/*extern*/ void register_http_service(http_service *svc)
+{
+    // simply hosting the memory of these http services.
+    static std::vector<std::unique_ptr<http_service>> services_holder;
+    static std::mutex mu;
+
+    std::lock_guard<std::mutex> guard(mu);
+    services_holder.push_back(std::unique_ptr<http_service>(svc));
 }
 
 } // namespace dsn

src/http/http_server_impl.h

@@ -0,0 +1,42 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <dsn/tool-api/rpc_message.h>
+#include <dsn/cpp/serverlet.h>
+#include <dsn/http/http_server.h>
+
+namespace dsn {
+
+class http_server : public serverlet<http_server>
+{
+public:
+    http_server();
+
+    ~http_server() override = default;
+
+    void serve(message_ex *msg);
+};
+
+extern void http_response_reply(const http_response &resp, message_ex *req);
+
+/// The rpc code for all the HTTP RPCs.
+/// Since http is used only for system monitoring, it is restricted to lowest priority.
+DEFINE_TASK_CODE_RPC(RPC_HTTP_SERVICE, TASK_PRIORITY_LOW, THREAD_POOL_DEFAULT);
+
+} // namespace dsn

src/http/test/http_server_test.cpp

@@ -8,6 +8,7 @@
 #include "http/http_message_parser.h"
 #include "http/root_http_service.h"
 #include "http/server_info_http_services.h"
+#include "http/http_server_impl.h"
 
 namespace dsn {
 

src/meta/meta_service_app.cpp

@@ -81,17 +81,17 @@ void meta_service_app::register_all()
     register_components();
 }
 
-meta_service_app::meta_service_app(const service_app_info *info)
-    : service_app(info), _http_server(new http_server())
+meta_service_app::meta_service_app(const service_app_info *info) : service_app(info)
 {
     // create in constructor because it may be used in checker before started
     _service.reset(new replication::meta_service());
 
     // add http service
     _version_http_service = new version_http_service();
-    _http_server->add_service(new replication::meta_http_service(_service.get()));
-    _http_server->add_service(new recent_start_time_http_service());
-    _http_server->add_service(_version_http_service);
+    register_http_service(new replication::meta_http_service(_service.get()));
+    register_http_service(new recent_start_time_http_service());
+    register_http_service(_version_http_service);
+    start_http_server();
 }
 
 meta_service_app::~meta_service_app() {}

src/replica/replication_service_app.cpp

@@ -40,16 +40,15 @@ void replication_service_app::register_all()
     dsn::service_app::register_factory<replication_service_app>("replica");
 }
 
-replication_service_app::replication_service_app(const service_app_info *info)
-    : service_app(info), _http_server(new http_server())
+replication_service_app::replication_service_app(const service_app_info *info) : service_app(info)
 {
     _stub = new replica_stub();
 
     // add http service
     _version_http_service = new version_http_service();
-    _http_server->add_service(_version_http_service);
-    _http_server->add_service(new recent_start_time_http_service());
-    _http_server->add_service(new replica_http_service(_stub.get()));
+    register_http_service(_version_http_service);
+    register_http_service(new recent_start_time_http_service());
+    register_http_service(new replica_http_service(_stub.get()));
 }
 
 replication_service_app::~replication_service_app(void) {}