1 files changed, 96 insertions, 0 deletions
diff --git a/src/main/java/org/traccar/schedule/TaskHealthCheck.java b/src/main/java/org/traccar/schedule/TaskHealthCheck.java
new file mode 100644
index 000000000..a8c9873ce
--- /dev/null
+++ b/src/main/java/org/traccar/schedule/TaskHealthCheck.java
@@ -0,0 +1,96 @@
+/*
+ * Copyright 2020 - 2022 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.schedule;
+
+import com.sun.jna.Library;
+import com.sun.jna.Native;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.traccar.config.Config;
+import org.traccar.config.Keys;
+
+import javax.inject.Inject;
+import javax.ws.rs.client.Client;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+public class TaskHealthCheck implements ScheduleTask {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(TaskHealthCheck.class);
+
+    private final Config config;
+    private final Client client;
+
+    private SystemD systemD;
+
+    private boolean enabled;
+    private long period;
+
+    @Inject
+    public TaskHealthCheck(Config config, Client client) {
+        this.config = config;
+        this.client = client;
+        if (!config.getBoolean(Keys.WEB_DISABLE_HEALTH_CHECK)
+                && 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);
+            }
+        }
+    }
+
+    private String getUrl() {
+        String address = config.getString(Keys.WEB_ADDRESS, "localhost");
+        int port = config.getInteger(Keys.WEB_PORT);
+        return "http://" + address + ":" + port + "/api/server";
+    }
+
+    @Override
+    public void schedule(ScheduledExecutorService executor) {
+        if (enabled) {
+            executor.scheduleAtFixedRate(this, period, period, TimeUnit.MILLISECONDS);
+        }
+    }
+
+    @Override
+    public void run() {
+        LOGGER.debug("Health check running");
+        int status = client.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 {
+        @SuppressWarnings("checkstyle:MethodName")
+        int sd_notify(@SuppressWarnings("checkstyle:ParameterName") int unset_environment, String state);
+    }
+
+}