redis broadcast service

1 files changed, 206 insertions, 0 deletions

diff --git a/src/main/java/org/traccar/broadcast/RedisBroadcastService.java b/src/main/java/org/traccar/broadcast/RedisBroadcastService.java
new file mode 100644
index 000000000..a6968c894
--- /dev/null
+++ b/src/main/java/org/traccar/broadcast/RedisBroadcastService.java
@@ -0,0 +1,206 @@
+/*
+ * Copyright 2023 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.broadcast;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.traccar.config.Config;
+import org.traccar.config.Keys;
+import org.traccar.model.BaseModel;
+import org.traccar.model.Device;
+import org.traccar.model.Event;
+import org.traccar.model.Permission;
+import org.traccar.model.Position;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import redis.clients.jedis.Jedis;
+import redis.clients.jedis.JedisPubSub;
+
+public class RedisBroadcastService implements BroadcastService {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(RedisBroadcastService.class);
+
+    private final ObjectMapper objectMapper;
+
+    private final ExecutorService service = Executors.newSingleThreadExecutor();
+
+    private final Set<BroadcastInterface> listeners = new HashSet<>();
+
+    private final String url;
+    private final String pubsubChannel = "traccar:cast";
+
+    private final Jedis subscriberJedis;
+    private final Jedis publisherJedis;
+
+    private final String id;
+
+    public RedisBroadcastService(Config config, ObjectMapper objectMapper) throws IOException {
+        this.objectMapper = objectMapper;
+        url = config.getString(Keys.BROADCAST_ADDRESS);
+
+        subscriberJedis = new Jedis(url);
+        publisherJedis = new Jedis(url);
+
+        // id that will be used to identify this instance of the server
+        id = String.valueOf(System.currentTimeMillis());
+    }
+
+    @Override
+    public boolean singleInstance() {
+        return false;
+    }
+
+    @Override
+    public void registerListener(BroadcastInterface listener) {
+        listeners.add(listener);
+    }
+
+    @Override
+    public void updateDevice(boolean local, Device device) {
+        BroadcastMessage message = new BroadcastMessage();
+        message.setDevice(device);
+        sendMessage(message);
+    }
+
+    @Override
+    public void updatePosition(boolean local, Position position) {
+        BroadcastMessage message = new BroadcastMessage();
+        message.setPosition(position);
+        sendMessage(message);
+    }
+
+    @Override
+    public void updateEvent(boolean local, long userId, Event event) {
+        BroadcastMessage message = new BroadcastMessage();
+        message.setUserId(userId);
+        message.setEvent(event);
+        sendMessage(message);
+    }
+
+    @Override
+    public void updateCommand(boolean local, long deviceId) {
+        BroadcastMessage message = new BroadcastMessage();
+        message.setCommandDeviceId(deviceId);
+        sendMessage(message);
+    }
+
+    @Override
+    public void invalidateObject(boolean local, Class<? extends BaseModel> clazz, long id) {
+        BroadcastMessage message = new BroadcastMessage();
+        message.setChanges(Map.of(Permission.getKey(clazz), id));
+        sendMessage(message);
+    }
+
+    @Override
+    public void invalidatePermission(
+            boolean local,
+            Class<? extends BaseModel> clazz1, long id1,
+            Class<? extends BaseModel> clazz2, long id2) {
+        BroadcastMessage message = new BroadcastMessage();
+        message.setChanges(Map.of(Permission.getKey(clazz1), id1, Permission.getKey(clazz2), id2));
+        sendMessage(message);
+    }
+
+    private void sendMessage(BroadcastMessage message) {
+        try {
+            String payload = id  + ":" + objectMapper.writeValueAsString(message);
+            publisherJedis.publish(pubsubChannel, payload);
+        } catch (IOException e) {
+            LOGGER.warn("Broadcast failed", e);
+        }
+    }
+
+    private void handleMessage(BroadcastMessage message) {
+        if (message.getDevice() != null) {
+            listeners.forEach(listener -> listener.updateDevice(false, message.getDevice()));
+        } else if (message.getPosition() != null) {
+            listeners.forEach(listener -> listener.updatePosition(false, message.getPosition()));
+        } else if (message.getUserId() != null && message.getEvent() != null) {
+            listeners.forEach(listener -> listener.updateEvent(false, message.getUserId(), message.getEvent()));
+        } else if (message.getCommandDeviceId() != null) {
+            listeners.forEach(listener -> listener.updateCommand(false, message.getCommandDeviceId()));
+        } else if (message.getChanges() != null) {
+            var iterator = message.getChanges().entrySet().iterator();
+            if (iterator.hasNext()) {
+                var first = iterator.next();
+                if (iterator.hasNext()) {
+                    var second = iterator.next();
+                    listeners.forEach(listener -> listener.invalidatePermission(
+                            false,
+                            Permission.getKeyClass(first.getKey()), first.getValue(),
+                            Permission.getKeyClass(second.getKey()), second.getValue()));
+                } else {
+                    listeners.forEach(listener -> listener.invalidateObject(
+                            false,
+                            Permission.getKeyClass(first.getKey()), first.getValue()));
+                }
+            }
+        }
+    }
+
+    @Override
+    public void start() throws IOException {
+        service.submit(receiver);
+    }
+
+    @Override
+    public void stop() {
+        service.shutdown();
+    }
+
+    private final Runnable receiver = new Runnable() {
+        @Override
+        public void run() {
+            subscriberJedis.subscribe(new JedisPubSub() {
+                @Override
+                public void onMessage(String channel, String message) {
+                    try {
+                        String[] parts = message.split(":", 2);
+                        if (channel == pubsubChannel && parts.length == 2 && !id.equals(parts[0])) {
+                            handleMessage(objectMapper.readValue(parts[1], BroadcastMessage.class));
+                        }
+                    } catch (IOException e) {
+                        LOGGER.warn("Broadcast handleMessage failed", e);
+                    }
+                }
+            }, pubsubChannel);
+
+            while (!service.isShutdown()) {
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                    break;
+                }
+            }
+
+            try {
+                subscriberJedis.close();
+                publisherJedis.close();
+            } catch (Exception e) {
+                LOGGER.warn("Failed to close pubsub", e);
+                throw new RuntimeException(e);
+            }
+        }
+    };
+
+}