Java tutorial
// // Licensed to the Apache Software Foundation (ASF) under one // or more contributor license agreements. See the NOTICE file // distributed with this work for additional information // regarding copyright ownership. The ASF licenses this file // to you 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 com.cloud.utils.ssh; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.nio.charset.StandardCharsets; import org.apache.commons.io.IOUtils; import org.apache.commons.lang.StringUtils; import org.apache.log4j.Logger; import com.trilead.ssh2.ChannelCondition; import com.trilead.ssh2.Connection; import com.trilead.ssh2.Session; import com.cloud.utils.Pair; public class SshHelper { private static final int DEFAULT_CONNECT_TIMEOUT = 180000; private static final int DEFAULT_KEX_TIMEOUT = 60000; /** * Waiting time to check if the SSH session was successfully opened. This value (of 1000 * milliseconds) represents one (1) second. */ private static final long WAITING_OPEN_SSH_SESSION = 1000; private static final Logger s_logger = Logger.getLogger(SshHelper.class); public static Pair<Boolean, String> sshExecute(String host, int port, String user, File pemKeyFile, String password, String command) throws Exception { return sshExecute(host, port, user, pemKeyFile, password, command, DEFAULT_CONNECT_TIMEOUT, DEFAULT_KEX_TIMEOUT, 120000); } public static void scpTo(String host, int port, String user, File pemKeyFile, String password, String remoteTargetDirectory, String localFile, String fileMode) throws Exception { scpTo(host, port, user, pemKeyFile, password, remoteTargetDirectory, localFile, fileMode, DEFAULT_CONNECT_TIMEOUT, DEFAULT_KEX_TIMEOUT); } public static void scpTo(String host, int port, String user, File pemKeyFile, String password, String remoteTargetDirectory, byte[] data, String remoteFileName, String fileMode) throws Exception { scpTo(host, port, user, pemKeyFile, password, remoteTargetDirectory, data, remoteFileName, fileMode, DEFAULT_CONNECT_TIMEOUT, DEFAULT_KEX_TIMEOUT); } public static void scpTo(String host, int port, String user, File pemKeyFile, String password, String remoteTargetDirectory, String localFile, String fileMode, int connectTimeoutInMs, int kexTimeoutInMs) throws Exception { com.trilead.ssh2.Connection conn = null; com.trilead.ssh2.SCPClient scpClient = null; try { conn = new com.trilead.ssh2.Connection(host, port); conn.connect(null, connectTimeoutInMs, kexTimeoutInMs); if (pemKeyFile == null) { if (!conn.authenticateWithPassword(user, password)) { String msg = "Failed to authentication SSH user " + user + " on host " + host; s_logger.error(msg); throw new Exception(msg); } } else { if (!conn.authenticateWithPublicKey(user, pemKeyFile, password)) { String msg = "Failed to authentication SSH user " + user + " on host " + host; s_logger.error(msg); throw new Exception(msg); } } scpClient = conn.createSCPClient(); if (fileMode != null) scpClient.put(localFile, remoteTargetDirectory, fileMode); else scpClient.put(localFile, remoteTargetDirectory); } finally { if (conn != null) conn.close(); } } public static void scpTo(String host, int port, String user, File pemKeyFile, String password, String remoteTargetDirectory, byte[] data, String remoteFileName, String fileMode, int connectTimeoutInMs, int kexTimeoutInMs) throws Exception { com.trilead.ssh2.Connection conn = null; com.trilead.ssh2.SCPClient scpClient = null; try { conn = new com.trilead.ssh2.Connection(host, port); conn.connect(null, connectTimeoutInMs, kexTimeoutInMs); if (pemKeyFile == null) { if (!conn.authenticateWithPassword(user, password)) { String msg = "Failed to authentication SSH user " + user + " on host " + host; s_logger.error(msg); throw new Exception(msg); } } else { if (!conn.authenticateWithPublicKey(user, pemKeyFile, password)) { String msg = "Failed to authentication SSH user " + user + " on host " + host; s_logger.error(msg); throw new Exception(msg); } } scpClient = conn.createSCPClient(); if (fileMode != null) scpClient.put(data, remoteFileName, remoteTargetDirectory, fileMode); else scpClient.put(data, remoteFileName, remoteTargetDirectory); } finally { if (conn != null) conn.close(); } } public static Pair<Boolean, String> sshExecute(String host, int port, String user, File pemKeyFile, String password, String command, int connectTimeoutInMs, int kexTimeoutInMs, int waitResultTimeoutInMs) throws Exception { com.trilead.ssh2.Connection conn = null; com.trilead.ssh2.Session sess = null; try { conn = new com.trilead.ssh2.Connection(host, port); conn.connect(null, connectTimeoutInMs, kexTimeoutInMs); if (pemKeyFile == null) { if (!conn.authenticateWithPassword(user, password)) { String msg = "Failed to authentication SSH user " + user + " on host " + host; s_logger.error(msg); throw new Exception(msg); } } else { if (!conn.authenticateWithPublicKey(user, pemKeyFile, password)) { String msg = "Failed to authentication SSH user " + user + " on host " + host; s_logger.error(msg); throw new Exception(msg); } } sess = openConnectionSession(conn); sess.execCommand(command); InputStream stdout = sess.getStdout(); InputStream stderr = sess.getStderr(); byte[] buffer = new byte[8192]; StringBuffer sbResult = new StringBuffer(); int currentReadBytes = 0; while (true) { throwSshExceptionIfStdoutOrStdeerIsNull(stdout, stderr); if ((stdout.available() == 0) && (stderr.available() == 0)) { int conditions = sess .waitForCondition( ChannelCondition.STDOUT_DATA | ChannelCondition.STDERR_DATA | ChannelCondition.EOF | ChannelCondition.EXIT_STATUS, waitResultTimeoutInMs); throwSshExceptionIfConditionsTimeout(conditions); if ((conditions & ChannelCondition.EXIT_STATUS) != 0) { break; } if (canEndTheSshConnection(waitResultTimeoutInMs, sess, conditions)) { break; } } while (stdout.available() > 0) { currentReadBytes = stdout.read(buffer); sbResult.append(new String(buffer, 0, currentReadBytes)); } while (stderr.available() > 0) { currentReadBytes = stderr.read(buffer); sbResult.append(new String(buffer, 0, currentReadBytes)); } } String result = sbResult.toString(); if (StringUtils.isBlank(result)) { try { result = IOUtils.toString(stdout, StandardCharsets.UTF_8); } catch (IOException e) { s_logger.error("Couldn't get content of input stream due to: " + e.getMessage()); return new Pair<Boolean, String>(false, result); } } if (sess.getExitStatus() == null) { //Exit status is NOT available. Returning failure result. s_logger.error(String.format( "SSH execution of command %s has no exit status set. Result output: %s", command, result)); return new Pair<Boolean, String>(false, result); } if (sess.getExitStatus() != null && sess.getExitStatus().intValue() != 0) { s_logger.error(String.format( "SSH execution of command %s has an error status code in return. Result output: %s", command, result)); return new Pair<Boolean, String>(false, result); } return new Pair<Boolean, String>(true, result); } finally { if (sess != null) sess.close(); if (conn != null) conn.close(); } } /** * It gets a {@link Session} from the given {@link Connection}; then, it waits * {@value #WAITING_OPEN_SSH_SESSION} milliseconds before returning the session, given a time to * ensure that the connection is open before proceeding the execution. */ protected static Session openConnectionSession(Connection conn) throws IOException, InterruptedException { Session sess = conn.openSession(); Thread.sleep(WAITING_OPEN_SSH_SESSION); return sess; } /** * Handles the SSH connection in case of timeout or exit. If the session ends with a timeout * condition, it throws an exception; if the channel reaches an end of file condition, but it * does not have an exit status, it returns true to break the loop; otherwise, it returns * false. */ protected static boolean canEndTheSshConnection(int waitResultTimeoutInMs, com.trilead.ssh2.Session sess, int conditions) throws SshException { if (isChannelConditionEof(conditions)) { int newConditions = sess.waitForCondition(ChannelCondition.EXIT_STATUS, waitResultTimeoutInMs); throwSshExceptionIfConditionsTimeout(newConditions); if ((newConditions & ChannelCondition.EXIT_STATUS) != 0) { return true; } } return false; } /** * It throws a {@link SshException} if the channel condition is {@link ChannelCondition#TIMEOUT} */ protected static void throwSshExceptionIfConditionsTimeout(int conditions) throws SshException { if ((conditions & ChannelCondition.TIMEOUT) != 0) { String msg = "Timed out in waiting for SSH execution exit status"; s_logger.error(msg); throw new SshException(msg); } } /** * Checks if the channel condition mask is of {@link ChannelCondition#EOF} and not * {@link ChannelCondition#STDERR_DATA} or {@link ChannelCondition#STDOUT_DATA}. */ protected static boolean isChannelConditionEof(int conditions) { if ((conditions & ChannelCondition.EOF) != 0) { return true; } return false; } /** * Checks if the SSH session {@link com.trilead.ssh2.Session#getStdout()} or * {@link com.trilead.ssh2.Session#getStderr()} is null. */ protected static void throwSshExceptionIfStdoutOrStdeerIsNull(InputStream stdout, InputStream stderr) throws SshException { if (stdout == null || stderr == null) { String msg = "Stdout or Stderr of SSH session is null"; s_logger.error(msg); throw new SshException(msg); } } }