Hot reload.

8 files changed, 129 insertions, 74 deletions

diff --git a/src/main/java/com/keuin/crosslink/api/ApiServer.java b/src/main/java/com/keuin/crosslink/api/ApiServer.java
index d7599a5..ebd1820 100644
--- a/src/main/java/com/keuin/crosslink/api/ApiServer.java
+++ b/src/main/java/com/keuin/crosslink/api/ApiServer.java
@@ -26,7 +26,7 @@ import java.util.stream.Collectors;
  */
 public class ApiServer implements IApiServer {
     private final Logger logger = LoggerFactory.getLogger(LoggerNaming.name().of("api").of("server").toString());
-    private HttpServer server = null;
+    private volatile HttpServer server = null;
     private final ICoreAccessor coreAccessor;
 
     @Inject
@@ -38,6 +38,7 @@ public class ApiServer implements IApiServer {
     @Override
     public void startup(InetSocketAddress listen) throws ApiStartupException {
         try {
+            if (this.server != null) throw new IllegalStateException("API server is already started.");
             this.server = HttpServer.create(listen, 0);
             ImmutableMap.<String, JsonReqHandler>builder()
                     .put("/", new JsonReqHandler("GET") {
diff --git a/src/main/java/com/keuin/crosslink/config/GlobalConfigManager.java b/src/main/java/com/keuin/crosslink/config/GlobalConfigManager.java
index 26996c2..fcc0321 100644
--- a/src/main/java/com/keuin/crosslink/config/GlobalConfigManager.java
+++ b/src/main/java/com/keuin/crosslink/config/GlobalConfigManager.java
@@ -1,35 +1,75 @@
 package com.keuin.crosslink.config;
 
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import org.jetbrains.annotations.NotNull;
 
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.Objects;
+import java.util.Optional;
 
 public class GlobalConfigManager {
+
+    private static final Object lock = new Object();
+    public static final ObjectMapper mapper = new ObjectMapper();
+
+    private volatile static GlobalConfigManager instance;
+    private JsonNode configMessaging; // mutable root node of file "messaging.json"
+    private JsonNode configApi; // mutable root node of file "api.json"
+
+    private GlobalConfigManager() {
+        mapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);
+    }
+
     /**
-     * Load config from disk.
+     * Load config from disk. Create the global instance.
      * If loaded successfully, the global 'loaded' status will be set to true.
+     *
      * @throws ConfigLoadException failed to load. The 'loaded' status will be set to false.
      */
-    public static void initializeGlobalManager(File configFile) throws ConfigLoadException {
-        // TODO read config from disk, create the singleton object
-//        throw new RuntimeException();
+    public static void initializeGlobalManager(@NotNull File configFile) throws ConfigLoadException, IOException {
+        Objects.requireNonNull(configFile);
+        synchronized (lock) {
+            if (instance == null) {
+                throw new IllegalStateException("already initialized");
+            }
+            instance = new GlobalConfigManager();
+        }
+        instance.loadConfig(configFile);
+    }
+
+    private void loadConfig(File configDirectory) throws IOException {
+        try (var fis = new FileInputStream(new File(configDirectory, "messaging.json"))) {
+            configMessaging = Optional.ofNullable(mapper.readTree(fis)).orElse(mapper.readTree("{}"));
+        }
+        try (var fis = new FileInputStream(new File(configDirectory, "api.json"))) {
+            configApi = Optional.ofNullable(mapper.readTree(fis)).orElse(mapper.readTree("{}"));
+        }
     }
 
     public static @NotNull GlobalConfigManager getInstance() {
-        // TODO get the singleton object
-//        throw new RuntimeException();
-        throw new RuntimeException("GlobalConfigManager is not initialized");
+        final var in = instance;
+        if (in == null) {
+            throw new RuntimeException("GlobalConfigManager is not initialized");
+        }
+        return in;
     }
 
     /**
-     * Get an immutable view of the global config.
-     * A view is a consistent, but not up-to-date snapshot.
-     *
-     * @return the config view.
+     * Config tree for messaging module.
      */
-    public IConfigView getConfig() {
-        // TODO
-        throw new RuntimeException("Global config is not loaded");
+    public @NotNull JsonNode messaging() {
+        return configMessaging.deepCopy();
+    }
+
+    /**
+     * Config tree for HTTP API module.
+     */
+    public @NotNull JsonNode api() {
+        return configApi.deepCopy();
     }
 
     public boolean isLoaded() {
@@ -39,9 +79,10 @@ public class GlobalConfigManager {
     /**
      * Reload the config file from disk.
      * If loaded successfully, the global 'loaded' status will be set to true.
+     *
      * @throws ConfigLoadException failed to reload.
-     * If previously loaded, the global config won't be modified.
-     * Otherwise, the 'loaded' status will be set to false.
+     *                             If previously loaded, the global config won't be modified.
+     *                             Otherwise, the 'loaded' status will be set to false.
      */
     public void reload() throws ConfigLoadException {
         // TODO
diff --git a/src/main/java/com/keuin/crosslink/config/IConfigView.java b/src/main/java/com/keuin/crosslink/config/IConfigView.java
deleted file mode 100644
index a3cab1b..0000000
--- a/src/main/java/com/keuin/crosslink/config/IConfigView.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package com.keuin.crosslink.config;
-
-public interface IConfigView {
-    int pingTimeoutMillis();
-}
diff --git a/src/main/java/com/keuin/crosslink/messaging/config/router/IRouterConfigurer.java b/src/main/java/com/keuin/crosslink/messaging/config/router/IRouterConfigurer.java
index 359ede4..a085b67 100644
--- a/src/main/java/com/keuin/crosslink/messaging/config/router/IRouterConfigurer.java
+++ b/src/main/java/com/keuin/crosslink/messaging/config/router/IRouterConfigurer.java
@@ -7,6 +7,7 @@ import com.keuin.crosslink.messaging.router.IRouterConfigurable;
 public interface IRouterConfigurer {
     /**
      * Parse and configure the router with internal configuration string.
+     * All existing endpoints and rule chains will be removed.
      * @throws JsonProcessingException cannot parse JSON string.
      * @throws ConfigSyntaxError config content is invalid.
      */
diff --git a/src/main/java/com/keuin/crosslink/messaging/config/router/RouterConfigurer.java b/src/main/java/com/keuin/crosslink/messaging/config/router/RouterConfigurer.java
index 578fcd5..1e4e718 100644
--- a/src/main/java/com/keuin/crosslink/messaging/config/router/RouterConfigurer.java
+++ b/src/main/java/com/keuin/crosslink/messaging/config/router/RouterConfigurer.java
@@ -243,6 +243,7 @@ public class RouterConfigurer implements IRouterConfigurer {
 
     @Override
     public void configure(IRouterConfigurable router) throws JsonProcessingException, ConfigSyntaxError {
+        router.clearEndpoints();
         router.updateRuleChain(loadRuleChain(router, config));
     }
 
diff --git a/src/main/java/com/keuin/crosslink/messaging/router/ConcreteRouter.java b/src/main/java/com/keuin/crosslink/messaging/router/ConcreteRouter.java
index 6433f8e..0888910 100644
--- a/src/main/java/com/keuin/crosslink/messaging/router/ConcreteRouter.java
+++ b/src/main/java/com/keuin/crosslink/messaging/router/ConcreteRouter.java
@@ -37,6 +37,10 @@ public class ConcreteRouter implements IRouter {
         return true;
     }
 
+    public void clearEndpoints() {
+        endpoints.clear();
+    }
+
     @Override
     public @NotNull Set<IEndpoint> resolveEndpoints(@NotNull String namespace, @NotNull Pattern idPattern) {
         Objects.requireNonNull(namespace);
diff --git a/src/main/java/com/keuin/crosslink/messaging/router/IRouterConfigurable.java b/src/main/java/com/keuin/crosslink/messaging/router/IRouterConfigurable.java
index d1871b9..aac1f93 100644
--- a/src/main/java/com/keuin/crosslink/messaging/router/IRouterConfigurable.java
+++ b/src/main/java/com/keuin/crosslink/messaging/router/IRouterConfigurable.java
@@ -41,4 +41,9 @@ public interface IRouterConfigurable {
     @NotNull Set<IEndpoint> resolveEndpoints(@NotNull String namespace, @NotNull Pattern idPattern);
 
     void updateRuleChain(@NotNull List<IRule> newChain);
+
+    /**
+     * Remove all existing endpoints.
+     */
+    void clearEndpoints();
 }
diff --git a/src/main/java/com/keuin/crosslink/plugin/common/PluginMain.java b/src/main/java/com/keuin/crosslink/plugin/common/PluginMain.java
index 288af95..aa97a0d 100644
--- a/src/main/java/com/keuin/crosslink/plugin/common/PluginMain.java
+++ b/src/main/java/com/keuin/crosslink/plugin/common/PluginMain.java
@@ -1,19 +1,18 @@
 package com.keuin.crosslink.plugin.common;
 
-import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
-import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.inject.Inject;
 import com.keuin.crosslink.api.IApiServer;
 import com.keuin.crosslink.api.error.ApiStartupException;
+import com.keuin.crosslink.config.ConfigLoadException;
+import com.keuin.crosslink.config.GlobalConfigManager;
 import com.keuin.crosslink.messaging.config.ConfigSyntaxError;
 import com.keuin.crosslink.messaging.config.remote.InvalidEndpointConfigurationException;
 import com.keuin.crosslink.messaging.config.remote.RemoteEndpointFactory;
 import com.keuin.crosslink.messaging.config.router.RouterConfigurer;
 import com.keuin.crosslink.messaging.endpoint.IEndpoint;
 import com.keuin.crosslink.messaging.router.IRouter;
-import com.keuin.crosslink.messaging.router.IRouterConfigurable;
 import com.keuin.crosslink.plugin.common.environ.PluginEnvironment;
 import com.keuin.crosslink.util.LoggerNaming;
 import com.keuin.crosslink.util.StartupMessagePrinter;
@@ -22,13 +21,14 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.File;
-import java.io.FileInputStream;
 import java.io.IOException;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.util.HashSet;
 import java.util.Optional;
 
+import static com.keuin.crosslink.config.GlobalConfigManager.mapper;
+
 public final class PluginMain {
     private final PluginEnvironment environment;
     private final IApiServer apiServer;
@@ -54,60 +54,53 @@ public final class PluginMain {
         // the plugin is not constructed here, so don't register event listener here
     }
 
-    public void enable() {
-        final ObjectMapper mapper = new ObjectMapper();
-        mapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);
-        // TODO refactor setup and teardown routine, split into hooks
-        // load config
-        // TODO global config (such as API config)
-        logger.info("Loading message routing configuration.");
-        JsonNode messagingConfig = null, routingConfig = null, remoteConfig = null;
-        try (var fis = new FileInputStream(new File(environment.pluginDataPath().toFile(), "messaging.json"))) {
-            messagingConfig = Optional.ofNullable(mapper.readTree(fis)).orElse(mapper.readTree("{}"));
-            routingConfig = Optional.ofNullable(messagingConfig.get("routing")).orElse(mapper.readTree("[]"));
-            remoteConfig = Optional.ofNullable(messagingConfig.get("remotes")).orElse(mapper.readTree("[]"));
-        } catch (IOException ex) {
-            logger.error("Failed to load message routing configuration", ex);
-            throw new RuntimeException(ex);
-        }
-
+    private void initialize() {
+        logger.info("Initializing components.");
         // initialize message routing
         logger.info("Initializing message routing.");
-        var endpoints = new HashSet<IEndpoint>();
+        var endpoints = new HashSet<>(coreAccessor.getServerEndpoints()); // All local and remote endpoints. remotes will be added later
         try {
+            var messaging = GlobalConfigManager.getInstance().messaging();
+            var routing = Optional.ofNullable(messaging.get("routing"))
+                    .orElse(mapper.readTree("[]"));
+            var remote = Optional.ofNullable(messaging.get("remotes"))
+                    .orElse(mapper.readTree("[]"));
+
+            // load routing table
             try {
                 logger.debug("Loading rule chain.");
-                var rc = new RouterConfigurer(routingConfig);
-                rc.configure(messageRouter);
+                var rc = new RouterConfigurer(routing);
+                rc.configure(messageRouter); // update routing table, clear endpoints
                 logger.debug("Message router is configured successfully.");
             } catch (JsonProcessingException | ConfigSyntaxError ex) {
-                throw new IRouterConfigurable.ConfigLoadException(ex);
+                logger.error("Failed to load routing config", ex);
+                throw new RuntimeException(ex);
             }
-            //noinspection CollectionAddAllCanBeReplacedWithConstructor
-            endpoints.addAll(coreAccessor.getServerEndpoints());
-        } catch (IRouter.ConfigLoadException ex) {
-            logger.error("Failed to read routing config", ex);
-            throw new RuntimeException(ex);
-        }
 
-        try {
-            logger.debug("Loading remote endpoints.");
-            if (!remoteConfig.isArray()) {
-                logger.error("Failed to load remote endpoints: remotes should be a JSON array.");
-                throw new RuntimeException("Invalid remotes type");
-            }
-            for (JsonNode remote : remoteConfig) {
-                var ep = RemoteEndpointFactory.create(remote);
-                if (ep != null) {
-                    logger.debug("Add remote endpoint: " + ep);
-                    endpoints.add(ep);
+            // load remote endpoints
+            try {
+                logger.debug("Loading remote endpoints.");
+                if (!remote.isArray()) {
+                    logger.error("Failed to load remote endpoints: remotes should be a JSON array.");
+                    throw new RuntimeException("Invalid remotes type");
                 }
+                for (var r : remote) {
+                    var ep = RemoteEndpointFactory.create(r);
+                    if (ep != null) {
+                        logger.debug("Add remote endpoint: " + ep);
+                        endpoints.add(ep);
+                    }
+                }
+            } catch (InvalidEndpointConfigurationException ex) {
+                logger.error("Invalid remote endpoint", ex);
+                throw new RuntimeException(ex);
             }
-        } catch (InvalidEndpointConfigurationException ex) {
-            logger.error("Invalid remote endpoint", ex);
+        } catch (JsonProcessingException ex) {
+            logger.error("Failed to parse JSON config", ex);
             throw new RuntimeException(ex);
         }
 
+        // register all endpoints on the router
         for (IEndpoint ep : endpoints) {
             if (!messageRouter.addEndpoint(ep)) {
                 logger.error("Cannot add endpoint " + ep);
@@ -117,8 +110,8 @@ public final class PluginMain {
         logger.info(String.format("Added %d sub-server(s) to message router.", endpoints.size()));
 
         logger.info("Starting API server.");
-        try (var fis = new FileInputStream(new File(environment.pluginDataPath().toFile(), "api.json"))) {
-            var apiConfig = Optional.ofNullable(mapper.readTree(fis)).orElse(mapper.readTree("{}"));
+        try {
+            var apiConfig = GlobalConfigManager.getInstance().api();
             var host = Optional.ofNullable(apiConfig.get("host")).map(JsonNode::textValue).orElse(null);
             if (host == null
                     || host.isEmpty()
@@ -129,13 +122,26 @@ public final class PluginMain {
             if (port <= 0) throw new ApiStartupException("Invalid port to listen on");
             // now the host is guaranteed to be an IP address string, so no DNS lookup will be performed
             apiServer.startup(new InetSocketAddress(InetAddress.getByName(host), port));
-        } catch (IOException ex) {
-            logger.error("Failed to load message routing configuration", ex);
-            throw new RuntimeException(ex);
-        } catch (ApiStartupException ex) {
+        } catch (IOException | ApiStartupException ex) {
             logger.error("Failed to start API server", ex);
-            return;
+            throw new RuntimeException(ex);
+        }
+
+        logger.info("Finish initializing.");
+    }
+
+    public void enable() {
+        // TODO refactor setup and teardown routine, split into hooks
+        logger.info("Loading config from disk...");
+        try {
+            GlobalConfigManager.initializeGlobalManager(new File(
+                    environment.pluginDataPath().toFile(), "messaging.json"));
+        } catch (ConfigLoadException | IOException ex) {
+            logger.error("Failed to load configuration", ex);
+            throw new RuntimeException(ex);
         }
+        logger.info("Config files are loaded.");
+        initialize();
         logger.info("CrossLink is enabled.");
     }
 
@@ -147,7 +153,8 @@ public final class PluginMain {
 
     // may throw unchecked exception
     public void reload() {
-        // TODO make api server and router reloadable
+        disable();
+        initialize();
     }
 
     private String capital(String s) {