feat(http): support CPU profiling using gperf (#290)

src/dist/http/pprof_http_service.cpp

@@ -20,6 +20,8 @@
 
 #include <cstdlib>
 #include <chrono>
+#include <fstream>
+#include <sstream>
 
 #include "pprof_http_service.h"
 
@@ -408,6 +410,59 @@ void pprof_http_service::growth_handler(const http_request &req, http_response &
     malloc_ext->GetHeapGrowthStacks(&resp.body);
 }
 
+//                             //
+// == ip:port/pprof/profile == //
+//                             //
+static bool get_cpu_profile(std::string &result, useconds_t seconds)
+{
+    const char *file_name = "cpu.prof";
+
+    ProfilerStart(file_name);
+    usleep(seconds);
+    ProfilerStop();
+
+    std::ifstream in(file_name);
+    if (!in.is_open()) {
+        result = "No profile file";
+        return false;
+    }
+    std::ostringstream content;
+    content << in.rdbuf();
+    result = content.str();
+    in.close();
+    if (remove(file_name) != 0) {
+        result = "Failed to remove temporary profile file";
+        return false;
+    }
+    return true;
+}
+
+void pprof_http_service::profile_handler(const http_request &req, http_response &resp)
+{
+    useconds_t seconds = 60000000;
+
+    const char *req_url = req.full_url.to_string().data();
+    size_t len = req.full_url.length();
+    string_splitter url_sp(req_url, req_url + len, '?');
+    if (url_sp != NULL && ++url_sp != NULL) {
+        string_splitter param_sp(url_sp.field(), url_sp.field() + url_sp.length(), '&');
+        while (param_sp != NULL) {
+            string_splitter kv_sp(param_sp.field(), param_sp.field() + param_sp.length(), '=');
+            std::string key(kv_sp.field(), kv_sp.length());
+            if (kv_sp != NULL && key == "seconds" && ++kv_sp != NULL) {
+                char *end_ptr;
+                seconds = strtoul(kv_sp.field(), &end_ptr, 10) * 1000000;
+                break;
+            }
+            param_sp++;
+        }
+    }
+
+    resp.status_code = http_status_code::ok;
+
+    get_cpu_profile(resp.body, seconds);
+}
+
 } // namespace dsn
 
 #endif // DSN_ENABLE_GPERF

src/dist/http/pprof_http_service.h

@@ -42,6 +42,13 @@ class pprof_http_service : public http_service
                                    this,
                                    std::placeholders::_1,
                                    std::placeholders::_2));
+
+        // ip:port/pprof/profile
+        register_handler("profile",
+                         std::bind(&pprof_http_service::profile_handler,
+                                   this,
+                                   std::placeholders::_1,
+                                   std::placeholders::_2));
     }
 
     std::string path() const override { return "pprof"; }
@@ -53,6 +60,8 @@ class pprof_http_service : public http_service
     void cmdline_handler(const http_request &req, http_response &resp);
 
     void growth_handler(const http_request &req, http_response &resp);
+
+    void profile_handler(const http_request &req, http_response &resp);
 };
 
 } // namespace dsn