Support health monitoring

4 files changed, 130 insertions, 23 deletions

diff --git a/setup/default.xml b/setup/default.xml
index 1d82ad926..561b57a57 100644
--- a/setup/default.xml
+++ b/setup/default.xml
@@ -14,6 +14,7 @@
     <entry key='web.port'>8082</entry>
     <entry key='web.path'>./web</entry>
     <entry key='web.cacheControl'>max-age=3600,public</entry>
+    <entry key='web.healthCheck'>true</entry>
 
     <entry key='geocoder.enable'>false</entry>
     <entry key='geocoder.type'>google</entry>
diff --git a/setup/traccar.service b/setup/traccar.service
index fe746dda8..6ae24ab8a 100644
--- a/setup/traccar.service
+++ b/setup/traccar.service
@@ -8,6 +8,9 @@ WorkingDirectory=/opt/traccar
 ExecStart=/opt/traccar/jre/bin/java -jar tracker-server.jar conf/traccar.xml
 SyslogIdentifier=traccar
 SuccessExitStatus=143
+WatchdogSec=100
+Restart=on-failure
+RestartSec=10
 
 [Install]
 WantedBy=multi-user.target
diff --git a/src/main/java/org/traccar/Main.java b/src/main/java/org/traccar/Main.java
index 6ebd1d399..f5690b26d 100644
--- a/src/main/java/org/traccar/Main.java
+++ b/src/main/java/org/traccar/Main.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 - 2019 Anton Tananaev (anton@traccar.org)
+ * Copyright 2012 - 2020 Anton Tananaev (anton@traccar.org)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@ import com.google.inject.Guice;
 import com.google.inject.Injector;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.traccar.api.HealthCheckService;
 
 import java.lang.management.ManagementFactory;
 import java.lang.management.MemoryMXBean;
@@ -105,6 +106,27 @@ public final class Main {
         }
     }
 
+    private static void scheduleHealthCheck() {
+        HealthCheckService service = new HealthCheckService();
+        if (service.isEnabled()) {
+            new Timer().scheduleAtFixedRate(
+                    service.createTask(), service.getPeriod(), service.getPeriod());
+        }
+    }
+
+    private static void scheduleDatabaseCleanup() {
+        new Timer().scheduleAtFixedRate(new TimerTask() {
+            @Override
+            public void run() {
+                try {
+                    Context.getDataManager().clearHistory();
+                } catch (SQLException error) {
+                    LOGGER.warn("Clear history error", error);
+                }
+            }
+        }, 0, CLEAN_PERIOD);
+    }
+
     public static void run(String configFile) {
         try {
             Context.init(configFile);
@@ -118,35 +140,26 @@ public final class Main {
                 Context.getWebServer().start();
             }
 
-            new Timer().scheduleAtFixedRate(new TimerTask() {
+            new Timer().schedule(new TimerTask() {
                 @Override
                 public void run() {
-                    try {
-                        Context.getDataManager().clearHistory();
-                    } catch (SQLException error) {
-                        LOGGER.warn("Clear history error", error);
-                    }
+                    Context.getWebServer().stop();
                 }
-            }, 0, CLEAN_PERIOD);
+            }, 10 * 60 * 1000);
 
-            Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
-                @Override
-                public void uncaughtException(Thread t, Throwable e) {
-                    LOGGER.error("Thread exception", e);
-                }
-            });
+            scheduleHealthCheck();
+            scheduleDatabaseCleanup();
 
-            Runtime.getRuntime().addShutdownHook(new Thread() {
-                @Override
-                public void run() {
-                    LOGGER.info("Shutting down server...");
+            Thread.setDefaultUncaughtExceptionHandler((t, e) -> LOGGER.error("Thread exception", e));
+
+            Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+                LOGGER.info("Shutting down server...");
 
-                    if (Context.getWebServer() != null) {
-                        Context.getWebServer().stop();
-                    }
-                    Context.getServerManager().stop();
+                if (Context.getWebServer() != null) {
+                    Context.getWebServer().stop();
                 }
-            });
+                Context.getServerManager().stop();
+            }));
         } catch (Exception e) {
             LOGGER.error("Main method error", e);
             throw new RuntimeException(e);
diff --git a/src/main/java/org/traccar/api/HealthCheckService.java b/src/main/java/org/traccar/api/HealthCheckService.java
new file mode 100644
index 000000000..cd2856dfa
--- /dev/null
+++ b/src/main/java/org/traccar/api/HealthCheckService.java
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2020 Anton Tananaev (anton@traccar.org)
+ *
+ * Licensed 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.
+ */
+package org.traccar.api;
+
+import com.sun.jna.Library;
+import com.sun.jna.Native;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.traccar.Context;
+
+import java.util.TimerTask;
+
+public class HealthCheckService {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(HealthCheckService.class);
+
+    private SystemD systemD;
+
+    private boolean enabled;
+    private long period;
+
+    public HealthCheckService() {
+        if (Context.getConfig().getBoolean("web.healthCheck")
+                && System.getProperty("os.name").toLowerCase().startsWith("linux")) {
+            try {
+                systemD = Native.load("systemd", SystemD.class);
+                String watchdogTimer = System.getenv("WATCHDOG_USEC");
+                if (watchdogTimer != null && !watchdogTimer.isEmpty()) {
+                    period = Long.parseLong(watchdogTimer) / 1000 * 4 / 5;
+                }
+                if (period > 0) {
+                    LOGGER.info("Health check enabled with period {}", period);
+                    enabled = true;
+                }
+            } catch (UnsatisfiedLinkError e) {
+                LOGGER.warn("No systemd support", e);
+            }
+        }
+    }
+
+    public boolean isEnabled() {
+        return enabled;
+    }
+
+    public long getPeriod() {
+        return period;
+    }
+
+    private String getUrl() {
+        String address = Context.getConfig().getString("web.address", "localhost");
+        int port = Context.getConfig().getInteger("web.port", 8082);
+        return "http://" + address + ":" + port + "/api/server";
+    }
+
+    public TimerTask createTask() {
+        return new TimerTask() {
+            @Override
+            public void run() {
+                LOGGER.debug("Health check running");
+                int status = Context.getClient().target(getUrl()).request().get().getStatus();
+                if (status == 200) {
+                    int result = systemD.sd_notify(0, "WATCHDOG=1");
+                    if (result < 0) {
+                        LOGGER.warn("Health check notify error {}", result);
+                    }
+                } else {
+                    LOGGER.warn("Health check failed with status {}", status);
+                }
+            }
+        };
+    }
+
+    interface SystemD extends Library {
+        int sd_notify(int unset_environment, String state);
+    }
+
+}