refactor(http): add http handler without creating http service (#615)

include/dsn/dist/replication/meta_service_app.h

@@ -59,7 +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;
-    version_http_service *_version_http_service;
 };
 } // namespace service
 } // namespace dsn

include/dsn/dist/replication/replication_service_app.h

@@ -70,10 +70,6 @@ class replication_service_app : public ::dsn::service_app
 private:
     friend class ::dsn::replication::test::test_checker;
     replica_stub_ptr _stub;
-    version_http_service *_version_http_service;
-
-    static const char *replica_service_app_info(int argc, char **argv);
-    static void replica_service_app_info_free(const char *response);
 };
 } // namespace replication
 } // namespace dsn

include/dsn/http/http_server.h

@@ -4,9 +4,6 @@
 
 #pragma once
 
-#include <dsn/c/api_common.h>
-#include <dsn/tool-api/rpc_message.h>
-#include <dsn/cpp/serverlet.h>
 #include <dsn/utility/errors.h>
 #include <dsn/utility/flags.h>
 
@@ -20,6 +17,7 @@ enum http_method
     HTTP_METHOD_POST = 2,
 };
 
+class message_ex;
 struct http_request
 {
     static error_with<http_request> parse(dsn::message_ex *m);
@@ -59,6 +57,17 @@ struct http_call
     std::string path;
     std::string help;
     http_callback callback;
+
+    http_call &with_callback(http_callback cb)
+    {
+        callback = std::move(cb);
+        return *this;
+    }
+    http_call &with_help(std::string hp)
+    {
+        help = std::move(hp);
+        return *this;
+    }
 };
 
 // A suite of HTTP handlers coupled using the same prefix of the service.
@@ -74,11 +83,24 @@ class http_service
     void register_handler(std::string path, http_callback cb, std::string help);
 };
 
+// Example:
+//
+// ```
+// register_http_call("/meta/app")
+//     .with_callback(std::bind(&meta_http_service::get_app_handler,
+//                              this,
+//                              std::placeholders::_1,
+//                              std::placeholders::_2))
+//     .with_help("Gets the app information")
+//     .add_argument("app_name", HTTP_ARG_STRING);
+// ```
+extern http_call &register_http_call(std::string full_path);
+
 // Starts serving HTTP requests.
 // The internal HTTP server will reuse the rDSN server port.
 extern void start_http_server();
 
-// NOTE: the memory of `svc` will be transfered to the underlying registry.
+// NOTE: the memory of `svc` will be transferred to the underlying registry.
 // TODO(wutao): pass `svc` as a std::unique_ptr.
 extern void register_http_service(http_service *svc);
 

src/http/builtin_http_calls.cpp

@@ -0,0 +1,77 @@
+// 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.
+
+#include <dsn/utility/output_utils.h>
+#include <dsn/utility/time_utils.h>
+
+#include "builtin_http_calls.h"
+#include "http_call_registry.h"
+#include "pprof_http_service.h"
+
+namespace dsn {
+
+/*extern*/ void get_help_handler(const http_request &req, http_response &resp)
+{
+    utils::table_printer tp;
+    std::ostringstream oss;
+    auto calls = http_call_registry::instance().list_all_calls();
+    for (const auto &call : calls) {
+        tp.add_row_name_and_data(std::string("/") + call->path, call->help);
+    }
+    tp.output(oss, utils::table_printer::output_format::kJsonCompact);
+    resp.body = oss.str();
+    resp.status_code = http_status_code::ok;
+}
+
+/*extern*/ void get_recent_start_time_handler(const http_request &req, http_response &resp)
+{
+    char start_time[100];
+    dsn::utils::time_ms_to_date_time(dsn::utils::process_start_millis(), start_time, 100);
+    std::ostringstream out;
+    dsn::utils::table_printer tp;
+    tp.add_row_name_and_data("RecentStartTime", start_time);
+    tp.output(out, dsn::utils::table_printer::output_format::kJsonCompact);
+
+    resp.body = out.str();
+    resp.status_code = http_status_code::ok;
+}
+
+/*extern*/ void register_builtin_http_calls()
+{
+#ifdef DSN_ENABLE_GPERF
+    static pprof_http_service pprof_svc;
+#endif
+
+    register_http_call("")
+        .with_callback(
+            [](const http_request &req, http_response &resp) { get_help_handler(req, resp); })
+        .with_help("Lists all supported calls");
+
+    register_http_call("recentStartTime")
+        .with_callback([](const http_request &req, http_response &resp) {
+            get_recent_start_time_handler(req, resp);
+        })
+        .with_help("Gets the server start time.");
+
+    register_http_call("perfCounter")
+        .with_callback([](const http_request &req, http_response &resp) {
+            get_perf_counter_handler(req, resp);
+        })
+        .with_help("Gets the value of a perf counter");
+}
+
+} // namespace dsn

src/http/builtin_http_calls.h

@@ -0,0 +1,35 @@
+// 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/cpp/serverlet.h>
+#include <dsn/http/http_server.h>
+#include <dsn/utility/errors.h>
+
+namespace dsn {
+
+// Register basic services for the HTTP server.
+extern void register_builtin_http_calls();
+
+extern void get_perf_counter_handler(const http_request &req, http_response &resp);
+
+extern void get_help_handler(const http_request &req, http_response &resp);
+
+extern void get_recent_start_time_handler(const http_request &req, http_response &resp);
+
+} // namespace dsn

src/http/http_server.cpp

@@ -4,13 +4,13 @@
 
 #include <dsn/http/http_server.h>
 #include <dsn/tool_api.h>
+#include <dsn/utility/time_utils.h>
 #include <boost/algorithm/string.hpp>
 #include <fmt/ostream.h>
 
 #include "http_message_parser.h"
-#include "root_http_service.h"
 #include "pprof_http_service.h"
-#include "perf_counter_http_service.h"
+#include "builtin_http_calls.h"
 #include "uri_decoder.h"
 #include "http_call_registry.h"
 #include "http_server_impl.h"
@@ -38,6 +38,20 @@ DSN_DEFINE_bool("http", enable_http_server, true, "whether to enable the embedde
     }
 }
 
+/*extern*/ http_call &register_http_call(std::string full_path)
+{
+    auto call_ptr = dsn::make_unique<http_call>();
+    call_ptr->path = std::move(full_path);
+    http_call &call = *call_ptr;
+    http_call_registry::instance().add(std::move(call_ptr));
+    return call;
+}
+
+/*extern*/ void deregister_http_call(const std::string &full_path)
+{
+    http_call_registry::instance().remove(full_path);
+}
+
 void http_service::register_handler(std::string path, http_callback cb, std::string help)
 {
     if (!FLAGS_enable_http_server) {
@@ -64,13 +78,7 @@ 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
-    register_http_service(new root_http_service());
-
-#ifdef DSN_ENABLE_GPERF
-    register_http_service(new pprof_http_service());
-#endif // DSN_ENABLE_GPERF
-
-    register_http_service(new perf_counter_http_service());
+    register_builtin_http_calls();
 }
 
 void http_server::serve(message_ex *msg)

src/http/perf_counter_http_service.cpp

@@ -3,12 +3,11 @@
 // can be found in the LICENSE file in the root directory of this source tree.
 
 #include <dsn/utility/output_utils.h>
-#include "perf_counter_http_service.h"
+#include "builtin_http_calls.h"
 
 namespace dsn {
 
-void perf_counter_http_service::get_perf_counter_handler(const http_request &req,
-                                                         http_response &resp)
+void get_perf_counter_handler(const http_request &req, http_response &resp)
 {
     std::string perf_counter_name;
     for (const auto &p : req.query_args) {

src/http/pprof_http_service.cpp

@@ -26,6 +26,8 @@
 #include "pprof_http_service.h"
 
 #include <dsn/dist/fmt_logging.h>
+#include <dsn/c/api_layer1.h>
+#include <dsn/utility/process_utils.h>
 #include <dsn/utility/string_conv.h>
 #include <dsn/utility/defer.h>
 #include <dsn/utility/timer.h>