Implement heartbeat for uptime monitoring

You can now monitor the bot's uptime via any external tool that supports push heartbeats. The bots sends a GET request every 30 seconds to show that it's online. The URL is hardcoded for the moment, but very easy to change.

src/main/java/wtf/beatrice/hidekobot/Configuration.java

@@ -30,6 +30,10 @@ public class Configuration
     // used to count eg. uptime
     private static LocalDateTime startupTime;
 
+    // todo: allow people to set their own url
+    private static final String heartbeatLink = "https://status.beatrice.wtf/api/push/%apikey%?status=up&msg=OK&ping=";
+    private static String heartbeatApiKey = "";
+
 
     private static final String botVersion = "0.1.4-slash"; // we should probably find a way to make this consistent with Maven
     private static final String botName = "HidekoBot";
@@ -211,4 +215,15 @@ public class Configuration
      */
     public static LocalDateTime getStartupTime() { return startupTime; }
 
+    public static String getFullHeartBeatLink() {
+        return heartbeatLink.replace("%apikey%", heartbeatApiKey);
+    }
+    //todo javadocs
+    public static void setHeartBeatApiKey(String key) {
+        heartbeatApiKey = key;
+    }
+    public static String getHeartBeatApiKey() {
+        return heartbeatApiKey;
+    }
+
 }

src/main/java/wtf/beatrice/hidekobot/HidekoBot.java

@@ -13,6 +13,7 @@ import wtf.beatrice.hidekobot.listeners.SlashCommandCompleter;
 import wtf.beatrice.hidekobot.listeners.SlashCommandListener;
 import wtf.beatrice.hidekobot.runnables.CommandsUpdateTask;
 import wtf.beatrice.hidekobot.runnables.ExpiredMessageTask;
+import wtf.beatrice.hidekobot.runnables.HeartBeatTask;
 import wtf.beatrice.hidekobot.utils.Logger;
 import wtf.beatrice.hidekobot.utils.SlashCommandUtil;
 
@@ -79,8 +80,19 @@ public class HidekoBot
         if(args.length > 1) {
             List<String> argsList = new ArrayList<>(Arrays.asList(args).subList(1, args.length));
 
-            if(argsList.contains("verbose")) Configuration.setVerbose(true);
-            if(argsList.contains("refresh")) forceUpdateCommands = true;
+            for(int i = 0; i < argsList.size(); i++)
+            {
+                String arg = argsList.get(i);
+
+                if(arg.equals("verbose")) Configuration.setVerbose(true);
+                if(arg.equals("refresh")) forceUpdateCommands = true;
+                if(arg.startsWith("heartbeat="))
+                {
+                    String apiKey = arg.replaceAll(".*=", ""); //remove the "heartbeat=" part
+                    Configuration.setHeartBeatApiKey(apiKey);
+                }
+            }
+
         }
 
         // register listeners
@@ -120,6 +132,8 @@ public class HidekoBot
         scheduler.scheduleAtFixedRate(expiredMessageTask, 5, 5, TimeUnit.SECONDS); //every 5 seconds
         CommandsUpdateTask commandsUpdateTask = new CommandsUpdateTask();
         scheduler.scheduleAtFixedRate(commandsUpdateTask, 10, 300, TimeUnit.SECONDS); //every 5 minutes
+        HeartBeatTask heartBeatTask = new HeartBeatTask();
+        scheduler.scheduleAtFixedRate(heartBeatTask, 10, 30, TimeUnit.SECONDS); //every 30 seconds
 
         // register shutdown interrupt signal listener for proper shutdown.
         Signal.handle(new Signal("INT"), signal -> shutdown());

src/main/java/wtf/beatrice/hidekobot/runnables/HeartBeatTask.java

@@ -0,0 +1,53 @@
+package wtf.beatrice.hidekobot.runnables;
+
+import wtf.beatrice.hidekobot.Configuration;
+import wtf.beatrice.hidekobot.utils.Logger;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+public class HeartBeatTask implements Runnable
+{
+    private final Logger logger;
+
+    public HeartBeatTask()
+    {
+        logger = new Logger(getClass());
+    }
+
+
+
+    @Override
+    public void run()
+    {
+        String apiKey = Configuration.getHeartBeatApiKey();
+        if(apiKey == null || apiKey.isEmpty()) return;
+
+        String urlString = Configuration.getFullHeartBeatLink();
+        try {
+
+            URL heartbeatUrl = new URL(urlString);
+
+            HttpURLConnection connection = (HttpURLConnection) heartbeatUrl.openConnection();
+            connection.setRequestMethod("GET");
+            connection.setConnectTimeout(5000);
+            connection.setReadTimeout(5000);
+
+            int responseCode = connection.getResponseCode();
+            if(200 <= responseCode && responseCode < 300)
+            {
+                // only log ok response codes when verbosity is enabled
+                if(Configuration.isVerbose()) logger.log("Heartbeat response code: " + responseCode);
+            }
+            else
+            {
+                logger.log("Heartbeat returned problematic response code: " + responseCode);
+            }
+
+        } catch (IOException e) {
+            logger.log("Error while trying to push heartbeat: " + e.getMessage());
+        }
+
+    }
+}