Add loadavg

DOCUMENTATION.md

@@ -44,6 +44,27 @@ Sample response
 * All responses are in kB
 * Same as /proc/meminfo file
 
+[GET] /proc/loadavg
+-------------------
+
+* returns system load averaged over 1, 5, and 10 mins
+* returns number of currently running processes over the total number of
+  process
+* returns the last proccessed PID used
+* Same as /proc/loadavg file
+
+Sample response
+
+```
+{
+  "1" : 0.56,
+  "5" : 0.69,
+  "10" : 1.30,
+  "processes" : "2/849",
+  "lastPID" : 28225,
+}
+```
+
 Special formatted responses
 ===========================
 
@@ -55,18 +76,7 @@ Special formatted responses
 [GET] /load
 ----------
 
-* Returns load average over the past 1, 5, and 10 mins
-* formatted version of /proc/loadavg
-
-Sample response
-
-```
-{
-  "1" : 0.56
-  "5" : 0.69
-  "10" : 1.30
-}
-```
+* Returns a redirect to /proc/loadavg
 
 [GET] /mem
 ----------

src/components/state.cpp

@@ -7,7 +7,7 @@
 #include "state.hpp"
 
 bool state::getUptime(crow::json::wvalue& ret){
-    std::ifstream f ("/proc/uptime");
+    std::ifstream f (procuptimepath);
     std::string line;
     if(f.is_open()){
         int space = -1;
@@ -34,10 +34,54 @@ bool state::getUptime(crow::json::wvalue& ret){
 }
 
 bool state::getRawUptime(std::string& ret){
-    std::ifstream f ("/proc/uptime");
+    std::ifstream f (procuptimepath);
     if(f.is_open()){
         std::getline(f, ret);
-        ret += "\n";
+        ret += '\n';
+        f.close();
+    } else {
+        ret = "Failed to open proc filesystem";
+        return false;
+    }
+
+    return true;
+}
+
+bool state::getLoadAvg(crow::json::wvalue& ret){
+    std::ifstream f (procloadavgpath);
+    std::string line;
+    if(f.is_open()){
+        int spaces[4];
+        int ind = 0;
+        std::getline(f, line);
+
+        for(int i = 0; line[i] != '\0'; ++i){
+            if(line[i] == ' '){
+                spaces[ind] = i;
+                ++ind;
+            }
+        }
+
+        ret["1"] = std::stof(line.substr(0,spaces[0]));
+        ret["5"] = std::stof(line.substr(spaces[0] + 1, spaces[1] - spaces[0]));
+        ret["10"] = std::stof(line.substr(spaces[1] + 1, spaces[2] - spaces[1]));
+        ret["processes"] = line.substr(spaces[2] + 1, spaces[3] - spaces[2] - 1);
+        ret["lastPID"] = std::stoi(line.substr(spaces[3] + 1));
+
+        f.close();
+    } else {
+        ret["message"] = "Failed to open proc filesystem";
+        return false;
+    }
+
+    return true;
+}
+
+bool state::getRawLoadAvg(std::string& ret){
+    std::ifstream f (procloadavgpath);
+    if(f.is_open()){
+        std::getline(f, ret);
+        ret += '\n';
         f.close();
     } else {
         ret = "Failed to open proc filesystem";

src/components/state.hpp

@@ -11,7 +11,12 @@
 #include <string>
 #include <fstream>
 
+constexpr char procuptimepath[] = "/proc/uptime";
+constexpr char procloadavgpath[] = "/proc/loadavg";
+
 namespace state{
     bool getUptime(crow::json::wvalue&);
     bool getRawUptime(std::string&);
+    bool getLoadAvg(crow::json::wvalue&);
+    bool getRawLoadAvg(std::string&);
 }

src/routes.cpp

@@ -56,4 +56,27 @@ void setRoutes(crow::SimpleApp& app){
         return ret;
     });
 
+    CROW_ROUTE(app, "/proc/loadavg")([](const crow::request& req){
+        bool status;
+        std::string accept = req.get_header_value("Accept");
+
+        std::transform(accept.begin(), accept.end(), accept.begin(), ::tolower);
+
+        if(accept == "text/plain"){
+            accept.clear();
+            status = state::getRawLoadAvg(accept);
+            return crow::response(status ? 200 : 503, accept);
+        } else {
+            crow::json::wvalue json;
+            status = state::getLoadAvg(json);
+            return crow::response(status ? 200 : 503, json.dump());
+        }
+    });
+
+    CROW_ROUTE(app, "/load")([](){
+        crow::response ret;
+        ret.moved_perm("/proc/loadavg");
+        return ret;
+    });
+
 }