Jenkins插件学习之ssh-slaves-plugins插件

分析 slave 上的remtoe fs 目录什么时候创建, 创建的权限为什么是700??

首先在hudson/plugins/sshslaves/SSHLauncher.java文件中
这个方法是 启动 ssh slave的 入口
public void launch(final SlaveComputer computer, final TaskListener listener) throws InterruptedException {


connection = new Connection(host, port);
launcherExecutorService = Executors.newSingleThreadExecutor(new NamingThreadFactory(Executors.defaultThreadFactory(), "SSHLauncher.launch for '" + computer.getName() + "' node"));

然后其中加了一个 回调. 这个回调会在后面调用,这里使用先加上了.
Set<Callable<Boolean>> callables = new HashSet<>();
callables.add(new Callable<Boolean>() {
    copyAgentJar(listener, workingDirectory); //
});//添加回调结束


final ExecutorService srv = launcherExecutorService;

回调是在这里真正调用的
results = srv.invokeAll(callables);

/**
  * Method copies the agent jar to the remote system.
  *
  * @param listener         The listener.
  * @param workingDirectory The directory into which the agent jar will be copied.
  *
  * @throws IOException If something goes wrong.
  */
 @edu.umd.cs.findbugs.annotations.SuppressFBWarnings(
   value="RCN_REDUNDANT_NULLCHECK_WOULD_HAVE_BEEN_A_NPE",
   justification="there is a bug related with Java 11 bytecode see https://github.com/spotbugs/spotbugs/issues/756")
 private void copyAgentJar(TaskListener listener, String workingDirectory) throws IOException, InterruptedException {
     String fileName = workingDirectory + SLASH_AGENT_JAR;

     listener.getLogger().println(Messages.SSHLauncher_StartingSFTPClient(getTimestamp()));
     SFTPClient sftpClient = null;
     try {
         sftpClient = new SFTPClient(connection);

         try {
             SFTPv3FileAttributes fileAttributes = sftpClient._stat(workingDirectory);
             if (fileAttributes==null) {
                 listener.getLogger().println(Messages.SSHLauncher_RemoteFSDoesNotExist(getTimestamp(), workingDirectory));
                 sftpClient.mkdirs(workingDirectory, 0700);
             } else if (fileAttributes.isRegularFile()) {
                 throw new IOException(Messages.SSHLauncher_RemoteFSIsAFile(workingDirectory));
             }

             listener.getLogger().println(Messages.SSHLauncher_CopyingAgentJar(getTimestamp()));
             byte[] agentJar = new Slave.JnlpJar(AGENT_JAR).readFully();

             // If the agent jar already exists see if it needs to be updated
             boolean overwrite = true;
             if (sftpClient.exists(fileName)) {
                 String sourceAgentHash = getMd5Hash(agentJar);
                 String existingAgentHash = getMd5Hash(readInputStreamIntoByteArrayAndClose(sftpClient.read(fileName)));
                 listener.getLogger().println(MessageFormat.format( "Source agent hash is {0}. "
                   + "Installed agent hash is {1}", sourceAgentHash, existingAgentHash));

                 overwrite = !sourceAgentHash.equals(existingAgentHash);
             }

             if (overwrite) {
                 try {
                     // try to delete the file in case the agent we are copying is shorter than the agent
                     // that is already there
                     sftpClient.rm(fileName);
                 } catch (IOException e) {
                     // the file did not exist... so no need to delete it!
                 }

                 try (OutputStream os = sftpClient.writeToFile(fileName)) {
                     os.write(agentJar);
                     listener.getLogger()
                       .println(Messages.SSHLauncher_CopiedXXXBytes(getTimestamp(), agentJar.length));
                 } catch (Error error) {
                     throw error;
                 } catch (Throwable e) {
                     throw new IOException(Messages.SSHLauncher_ErrorCopyingAgentJarTo(fileName), e);
                 }
             }else{
                 listener.getLogger().println("Verified agent jar. No update is necessary.");
             }
         } catch (Error error) {
             throw error;
         } catch (Throwable e) {
             throw new IOException(Messages.SSHLauncher_ErrorCopyingAgentJarInto(workingDirectory), e);
         }
     } catch (IOException e) {
         if (sftpClient == null) {
             e.printStackTrace(listener.error(Messages.SSHLauncher_StartingSCPClient(getTimestamp())));
             // lets try to recover if the agent doesn't have an SFTP service
             copySlaveJarUsingSCP(listener, workingDirectory);
         } else {
             throw e;
         }
     } finally {
         if (sftpClient != null) {
             sftpClient.close();
         }
     }
 }

/**
 * Starts the agent process.
 *
 * @param computer         The computer.
 * @param listener         The listener.
 * @param java             The full path name of the java executable to use.
 * @param workingDirectory The working directory from which to start the java process.
 * @throws IOException If something goes wrong.
 */
private void startAgent(SlaveComputer computer, final TaskListener listener, String java, String workingDirectory) throws IOException {
  session = connection.openSession();
  expandChannelBufferSize(session, listener);
  String cmd = "cd \"" + workingDirectory + "\" && " + java + " " + getJvmOptions() + " -jar " + AGENT_JAR +
    getWorkDirParam(workingDirectory);

  //This will wrap the cmd with prefix commands and suffix commands if they are set.
  cmd = getPrefixStartSlaveCmd() + cmd + getSuffixStartSlaveCmd();

  listener.getLogger().println(Messages.SSHLauncher_StartingAgentProcess(getTimestamp(), cmd));
  session.execCommand(cmd);

  session.pipeStderr(new DelegateNoCloseOutputStream(listener.getLogger()));

  try {
    computer.setChannel(session.getStdout(), session.getStdin(), listener.getLogger(), null);
  } catch (InterruptedException e) {
    session.close();
    throw new IOException(Messages.SSHLauncher_AbortedDuringConnectionOpen(), e);
  } catch (IOException e) {
    try {
      // often times error this early means the JVM has died, so let's see if we can capture all stderr
      // and exit code
      throw new AbortException(getSessionOutcomeMessage(session, false));
    } catch (InterruptedException x) {
      throw new IOException(e);
    }
  }
}

Remote_root_directory and Remoting_Work_directory分析

分析得到 slave上 可以设置2中 directory. 一种是 Remote_root_directory  一种是 Remoting_Work_directory.

.
├── Remote_root_directory
│   ├── remoting.jar
│   └── workspace
│       └── test
└── Remoting_Work_directory
    └── remoting
        ├── jarCache
        │   ├── 04
        │   │   └── D04F08030B7FF8337135F2FE2724A7.jar
        └── logs
            ├── remoting.log.0
            └── remoting.log.0.lck
Remote_root_directory 目录在这个方法中被创建     private void copyAgentJar(TaskListener listener, String workingDirectory) throws IOException, InterruptedException {
                   是通过这个创建的 sftpClient.mkdirs(workingDirectory, 0700);



Remoting_Work_directory.目录在这个方法中被创建  private void startAgent(SlaveComputer computer, final TaskListener listener, String java,  String workingDirectory) throws IOException {
    是通过这个创建的session.execCommand(cmd); 
    其中cmd是  java -jar remoting.jar -workDir /tmp/mamh/Remoting_Work_directory -jar-cache /tmp/mamh/Remoting_Work_directory/remoting/jarCache
    也就是说 Remoting_Work_directory 是在 remoteing.jar 这个包里面的创建的了



这个目录Remoting_Work_directory 主要存放了一些   remote相关的 缓存的jar包, 日志文件等.这个是 ssh-slave 插件 提供的一个设置项, 可以在 高级选项 展开看到的

这个目录Remote_root_directory 主要放了一个 remoting.jar 文件 和我们的jenkins job的 workspace 目录()