Java tutorial
/* * Copyright 2015-2016 Red Hat, Inc. and/or its affiliates * and other contributors as indicated by the @author tags. * * 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.hawkular.agent.monitor.cmd; import java.io.BufferedInputStream; import java.io.IOException; import java.io.InputStream; import java.util.HashMap; import java.util.Map; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.atomic.AtomicReference; import org.hawkular.agent.monitor.extension.MonitorServiceConfiguration; import org.hawkular.agent.monitor.log.AgentLoggers; import org.hawkular.agent.monitor.log.MsgLogger; import org.hawkular.agent.monitor.service.MonitorService; import org.hawkular.agent.monitor.util.Util; import org.hawkular.bus.common.BasicMessage; import org.hawkular.bus.common.BasicMessageWithExtraData; import org.hawkular.bus.common.BinaryData; import org.hawkular.cmdgw.api.ApiDeserializer; import org.hawkular.cmdgw.api.AuthMessage; import org.hawkular.cmdgw.api.Authentication; import org.hawkular.cmdgw.api.GenericErrorResponse; import org.hawkular.cmdgw.api.GenericErrorResponseBuilder; import com.squareup.okhttp.MediaType; import com.squareup.okhttp.RequestBody; import com.squareup.okhttp.Response; import com.squareup.okhttp.ResponseBody; import com.squareup.okhttp.ws.WebSocket; import com.squareup.okhttp.ws.WebSocketCall; import com.squareup.okhttp.ws.WebSocketListener; import okio.Buffer; import okio.BufferedSink; public class FeedCommProcessor implements WebSocketListener { private static final MsgLogger log = AgentLoggers.getLogger(FeedCommProcessor.class); private static final Map<String, Class<? extends Command<?, ?>>> VALID_COMMANDS; static { VALID_COMMANDS = new HashMap<>(); VALID_COMMANDS.put(AddDatasourceCommand.REQUEST_CLASS.getName(), AddDatasourceCommand.class); VALID_COMMANDS.put(AddJdbcDriverCommand.REQUEST_CLASS.getName(), AddJdbcDriverCommand.class); VALID_COMMANDS.put(DeployApplicationCommand.REQUEST_CLASS.getName(), DeployApplicationCommand.class); VALID_COMMANDS.put(DisableApplicationCommand.REQUEST_CLASS.getName(), DisableApplicationCommand.class); VALID_COMMANDS.put(EchoCommand.REQUEST_CLASS.getName(), EchoCommand.class); VALID_COMMANDS.put(EnableApplicationCommand.REQUEST_CLASS.getName(), EnableApplicationCommand.class); VALID_COMMANDS.put(ExecuteOperationCommand.REQUEST_CLASS.getName(), ExecuteOperationCommand.class); VALID_COMMANDS.put(ExportJdrCommand.REQUEST_CLASS.getName(), ExportJdrCommand.class); VALID_COMMANDS.put(GenericErrorResponseCommand.REQUEST_CLASS.getName(), GenericErrorResponseCommand.class); VALID_COMMANDS.put(RemoveDatasourceCommand.REQUEST_CLASS.getName(), RemoveDatasourceCommand.class); VALID_COMMANDS.put(RemoveJdbcDriverCommand.REQUEST_CLASS.getName(), RemoveJdbcDriverCommand.class); VALID_COMMANDS.put(RestartApplicationCommand.REQUEST_CLASS.getName(), RestartApplicationCommand.class); VALID_COMMANDS.put(StatisticsControlCommand.REQUEST_CLASS.getName(), StatisticsControlCommand.class); VALID_COMMANDS.put(UndeployApplicationCommand.REQUEST_CLASS.getName(), UndeployApplicationCommand.class); VALID_COMMANDS.put(UpdateDatasourceCommand.REQUEST_CLASS.getName(), UpdateDatasourceCommand.class); } private final int disconnectCode = 1000; private final String disconnectReason = "Shutting down FeedCommProcessor"; private final WebSocketClientBuilder webSocketClientBuilder; private final MonitorServiceConfiguration config; private final MonitorService discoveryService; private final String feedcommUrl; private final ExecutorService sendExecutor = Executors.newSingleThreadExecutor(); private final AtomicReference<ReconnectJobThread> reconnectJobThread = new AtomicReference<>(); private WebSocketCall webSocketCall; private WebSocket webSocket; // if this is true, this object should never reconnect private boolean destroyed = false; public FeedCommProcessor(WebSocketClientBuilder webSocketClientBuilder, MonitorServiceConfiguration config, String feedId, MonitorService discoveryService) { if (feedId == null || feedId.isEmpty()) { throw new IllegalArgumentException("Must have a valid feed ID to communicate with the server"); } this.webSocketClientBuilder = webSocketClientBuilder; this.config = config; this.discoveryService = discoveryService; try { StringBuilder url; url = Util.getContextUrlString(config.getStorageAdapter().getUrl(), config.getStorageAdapter().getFeedcommContext()); url.append("feed/").append(feedId); this.feedcommUrl = url.toString().replaceFirst("https?:", (config.getStorageAdapter().isUseSSL()) ? "wss:" : "ws:"); log.infoFeedCommUrl(this.feedcommUrl); } catch (Exception e) { throw new IllegalArgumentException("Cannot build URL to the server command-gateway endpoint", e); } } /** * @return true if this object is currently connected to the websocket. */ public boolean isConnected() { return webSocket != null; } /** * Connects to the websocket endpoint. This first attempts to disconnect to any existing connection. * If this object has previously been {@link #destroy() destroyed}, then the connect request is ignored. * * @throws Exception on failure */ public void connect() throws Exception { disconnect(); // disconnect to any old connection we had if (destroyed) { return; } log.debugf("About to connect a feed WebSocket client to endpoint [%s]", feedcommUrl); webSocketCall = webSocketClientBuilder.createWebSocketCall(feedcommUrl, null); webSocketCall.enqueue(this); } public void disconnect() { if (webSocket != null) { try { webSocket.close(disconnectCode, disconnectReason); } catch (Exception e) { log.warnFailedToCloseWebSocket(disconnectCode, disconnectReason, e); } webSocket = null; } if (webSocketCall != null) { try { webSocketCall.cancel(); } catch (Exception e) { log.errorCannotCloseWebSocketCall(e); } webSocketCall = null; } } /** * Call this when you know this processor object will never be used again. */ public void destroy() { this.destroyed = true; stopReconnectJobThread(); disconnect(); } /** * Sends a message to the server asynchronously. This method returns immediately; the message may not go out until * some time in the future. * * @param messageWithData the message to send */ public void sendAsync(BasicMessageWithExtraData<? extends BasicMessage> messageWithData) { if (webSocket == null) { throw new IllegalStateException("WebSocket connection was closed. Cannot send any messages"); } BasicMessage message = messageWithData.getBasicMessage(); configurationAuthentication(message); sendExecutor.execute(new Runnable() { @Override public void run() { try { if (messageWithData.getBinaryData() == null) { String messageString = ApiDeserializer.toHawkularFormat(message); Buffer buffer = new Buffer(); buffer.writeUtf8(messageString); RequestBody requestBody = RequestBody.create(WebSocket.TEXT, buffer.readByteArray()); FeedCommProcessor.this.webSocket.sendMessage(requestBody); } else { BinaryData messageData = ApiDeserializer.toHawkularFormat(message, messageWithData.getBinaryData()); RequestBody requestBody = new RequestBody() { @Override public MediaType contentType() { return WebSocket.BINARY; } @Override public void writeTo(BufferedSink bufferedSink) throws IOException { emitToSink(messageData, bufferedSink); } }; FeedCommProcessor.this.webSocket.sendMessage(requestBody); } } catch (Throwable t) { log.errorFailedToSendOverFeedComm(message.getClass().getName(), t); } } }); } /** * Sends a message to the server synchronously. This will return only when the message has been sent. * * @param messageWithData the message to send * @throws IOException if the message failed to be sent */ public void sendSync(BasicMessageWithExtraData<? extends BasicMessage> messageWithData) throws Exception { if (webSocket == null) { throw new IllegalStateException("WebSocket connection was closed. Cannot send any messages"); } BasicMessage message = messageWithData.getBasicMessage(); configurationAuthentication(message); if (messageWithData.getBinaryData() == null) { String messageString = ApiDeserializer.toHawkularFormat(message); Buffer buffer = new Buffer(); buffer.writeUtf8(messageString); RequestBody requestBody = RequestBody.create(WebSocket.TEXT, buffer.readByteArray()); FeedCommProcessor.this.webSocket.sendMessage(requestBody); } else { BinaryData messageData = ApiDeserializer.toHawkularFormat(message, messageWithData.getBinaryData()); RequestBody requestBody = new RequestBody() { @Override public MediaType contentType() { return WebSocket.BINARY; } @Override public void writeTo(BufferedSink bufferedSink) throws IOException { emitToSink(messageData, bufferedSink); } }; FeedCommProcessor.this.webSocket.sendMessage(requestBody); } } private void emitToSink(BinaryData in, BufferedSink out) throws RuntimeException { int bufferSize = 32768; try { InputStream input = new BufferedInputStream(in, bufferSize); byte[] buffer = new byte[bufferSize]; for (int bytesRead = input.read(buffer); bytesRead != -1; bytesRead = input.read(buffer)) { out.write(buffer, 0, bytesRead); out.flush(); } } catch (IOException ioe) { throw new RuntimeException("Failed to emit to sink", ioe); } } @Override public void onOpen(WebSocket webSocket, Response response) { this.webSocket = webSocket; stopReconnectJobThread(); log.infoOpenedFeedComm(feedcommUrl); } @Override public void onClose(int reasonCode, String reason) { webSocket = null; log.infoClosedFeedComm(feedcommUrl, reasonCode, reason); // We always want a connection - so try to get another one. // Note that we don't try to get another connection if we think we'll never get one; // This avoids a potential infinite loop of continually trying (and failing) to get a connection. // We also don't try to get another one if we were explicitly told to disconnect. if (!(disconnectCode == reasonCode && disconnectReason.equals(reason))) { switch (reasonCode) { case 1008: { // VIOLATED POLICY - don't try again since it probably will fail again (bad credentials?) break; } default: { startReconnectJobThread(); break; } } } } @Override public void onFailure(IOException e, Response response) { if (response == null) { // don't flood the log with these at the WARN level - its probably just because the server is down // and we can't reconnect - while the server is down, our reconnect logic will cause this error // to occur periodically. Our reconnect logic will log other messages. log.tracef("Feed communications had a failure - a reconnection is likely required: %s", e); } else { log.warnFeedCommFailure(response.toString(), e); } } @Override @SuppressWarnings({ "rawtypes", "unchecked" }) public void onMessage(ResponseBody responseBody) throws IOException { BasicMessageWithExtraData<? extends BasicMessage> response; String requestClassName = "?"; try { try { BasicMessageWithExtraData<? extends BasicMessage> msgWithData; if (responseBody.contentType().equals(WebSocket.TEXT)) { String nameAndJsonStr = responseBody.string(); msgWithData = new ApiDeserializer().deserialize(nameAndJsonStr); } else if (responseBody.contentType().equals(WebSocket.BINARY)) { InputStream input = responseBody.byteStream(); msgWithData = new ApiDeserializer().deserialize(input); } else { throw new IllegalArgumentException( "Unknown mediatype type, please report this bug: " + responseBody.contentType()); } log.debug("Received message from server"); BasicMessage msg = msgWithData.getBasicMessage(); requestClassName = msg.getClass().getName(); Class<? extends Command<?, ?>> commandClass = VALID_COMMANDS.get(requestClassName); if (commandClass == null) { log.errorInvalidCommandRequestFeed(requestClassName); String errorMessage = "Invalid command request: " + requestClassName; GenericErrorResponse errorMsg = new GenericErrorResponseBuilder().setErrorMessage(errorMessage) .build(); response = new BasicMessageWithExtraData<BasicMessage>(errorMsg, null); } else { Command command = commandClass.newInstance(); CommandContext context = new CommandContext(this, this.config, this.discoveryService); response = command.execute(msgWithData, context); } } finally { // must ensure response is closed; this assumes if it was a stream that the command is finished with it responseBody.close(); } } catch (Throwable t) { log.errorCommandExecutionFailureFeed(requestClassName, t); String errorMessage = "Command failed [" + requestClassName + "]"; GenericErrorResponse errorMsg = new GenericErrorResponseBuilder().setThrowable(t) .setErrorMessage(errorMessage).build(); response = new BasicMessageWithExtraData<BasicMessage>(errorMsg, null); } // send the response back to the server if (response != null) { try { sendSync(response); } catch (Exception e) { log.errorFailedToSendOverFeedComm(response.getClass().getName(), e); } } } @Override public void onPong(Buffer buffer) { // no-op } private void configurationAuthentication(BasicMessage message) { if (!(message instanceof AuthMessage)) { return; // this message doesn't need authentication } AuthMessage authMessage = (AuthMessage) message; Authentication auth = authMessage.getAuthentication(); if (auth != null) { return; // authentication already configured; assume whoever did it knew what they were doing and keep it } auth = new Authentication(); auth.setUsername(this.config.getStorageAdapter().getUsername()); auth.setPassword(this.config.getStorageAdapter().getPassword()); authMessage.setAuthentication(auth); } private void startReconnectJobThread() { ReconnectJobThread newReconnectJob = (!destroyed) ? new ReconnectJobThread() : null; ReconnectJobThread oldReconnectJob = reconnectJobThread.getAndSet(newReconnectJob); if (oldReconnectJob != null) { oldReconnectJob.interrupt(); } if (newReconnectJob != null) { newReconnectJob.start(); } } private void stopReconnectJobThread() { ReconnectJobThread reconnectJob = reconnectJobThread.getAndSet(null); if (reconnectJob != null) { reconnectJob.interrupt(); } } private class ReconnectJobThread extends Thread { public ReconnectJobThread() { super("Hawkular WildFly Monitor Websocket Reconnect Thread"); setDaemon(true); } @Override public void run() { int attemptCount = 0; final long sleepInterval = 1000L; boolean keepTrying = true; while (keepTrying && !destroyed) { try { attemptCount++; Thread.sleep(sleepInterval); if (!isConnected()) { // only log a message for each minute that passes in which we couldn't reconnect if (attemptCount % 60 == 0) { log.errorCannotReconnectToWebSocket(new Exception("Attempt #" + attemptCount)); } connect(); } else { keepTrying = false; } } catch (InterruptedException ie) { keepTrying = false; } catch (Exception e) { if (attemptCount % 60 == 0) { log.errorCannotReconnectToWebSocket(e); } } } } } }