feat: expand frame type to support stdout/stderr chan
This commit is contained in:
Aarnav Tale
parent
7dfcbef774
commit
55eacb59e9
12 changed files with 580 additions and 285 deletions
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@ -3,8 +3,6 @@ package sshutil
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import (
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"context"
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"errors"
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"io"
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"os"
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"strconv"
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"strings"
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@ -13,149 +11,128 @@ import (
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"golang.org/x/crypto/ssh"
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)
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type SshConnectParams struct {
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Hostname string
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Port int
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Username string
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Id string
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type SSHConnectPayload struct {
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SessionId string `cbor:"sessionId"`
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Username string `cbor:"username"`
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Hostname string `cbor:"hostname"`
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Port int `cbor:"port"`
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}
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func dialAndValidateTailscaleSSH(agent *tsnet.TSAgent, params SshConnectParams) (*ssh.Client, error) {
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func connectToTailscaleSSH(agent *tsnet.TSAgent, params SSHConnectPayload) (*ssh.Client, error) {
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log := util.GetLogger()
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addr := strings.Join([]string{params.Hostname, ":", strconv.Itoa(params.Port)}, "")
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log.Debug("Attempting to dial %s via Tailscale SSH", addr)
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conn, err := agent.Dial(context.Background(), "tcp", addr)
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log.Debug("Initiating Tailscale SSH connection to %s@%s", params.Username, addr)
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tailnetConn, err := agent.Dial(context.Background(), "tcp", addr)
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if err != nil {
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log.Error("Failed to connect to Tailscale SSH: %s", err)
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return nil, err
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}
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log.Debug("Connected to Tailscale SSH at %s", addr)
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log.Debug("Routed connection via tsnet to %s", addr)
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config := &ssh.ClientConfig{
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User: params.Username,
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// This isn't a concern because we are only dialing within the Tailnet
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// and every device is trusted and *should* be ACL accessible.
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HostKeyCallback: ssh.InsecureIgnoreHostKey(),
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}
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clientConn, chans, reqs, err := ssh.NewClientConn(conn, addr, config)
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conn, chans, reqs, err := ssh.NewClientConn(tailnetConn, addr, config)
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if err != nil {
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log.Error("Failed to create SSH client connection: %s", err)
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conn.Close()
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return nil, err
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}
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client := ssh.NewClient(clientConn, chans, reqs)
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sVer := string(client.ServerVersion())
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// At this point we have successfully connected to the node
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sshClient := ssh.NewClient(conn, chans, reqs)
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version := string(sshClient.ServerVersion())
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if !strings.Contains(sVer, "Tailscale") {
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log.Error("Connected to non-Tailscale SSH server: %s", sVer)
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if !strings.Contains(version, "Tailscale") {
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conn.Close()
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return nil, errors.New("not a Tailscale SSH server")
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return nil, errors.New("server is not running Tailscale SSH")
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}
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log.Info("Connected to SSH server running %s at %s", client.ServerVersion(), addr)
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return client, nil
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log.Info("Connected to %s@%s:%d via Tailscale SSH (%s)", params.Username, params.Hostname, params.Port, version)
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return sshClient, nil
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}
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func bindStdinToFd(sess *ssh.Session, fd int) error {
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log := util.GetLogger()
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sshIn := os.NewFile(uintptr(fd), "sshInput")
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if sshIn == nil {
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log.Error("Failed to create file from stdin fd %d", fd)
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return errors.New("failed to create file from stdin fd")
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}
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stdin, err := sess.StdinPipe()
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if err != nil {
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log.Error("Failed to get stdin pipe: %s", err)
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return err
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}
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go io.Copy(stdin, sshIn) // From Node → SSH session
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return nil
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}
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func bindStdoutToFd(sess *ssh.Session, fd int) error {
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log := util.GetLogger()
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sshOut := os.NewFile(uintptr(fd), "sshOutput")
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if sshOut == nil {
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log.Error("Failed to create file from stdout fd %d", fd)
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return errors.New("failed to create file from stdout fd")
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}
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stdout, err := sess.StdoutPipe()
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if err != nil {
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log.Error("Failed to get stdout pipe: %s", err)
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return err
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}
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go io.Copy(sshOut, stdout) // From SSH → Node
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return nil
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}
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func OpenSshPty(agent *tsnet.TSAgent, params SshConnectParams) (*ssh.Client, error) {
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func StartWebSSH(agent *tsnet.TSAgent, params SSHConnectPayload) {
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log := util.GetLogger()
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if agent == nil {
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log.Error("Tailscale agent is nil")
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return nil, errors.New("tailscale agent is nil")
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log.Error("tsnet.TSAgent is not initialized correctly")
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return
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}
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if params.Hostname == "" || params.Port <= 0 || params.Username == "" {
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log.Error("Invalid SSH connection parameters: %+v", params)
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return nil, errors.New("invalid SSH connection parameters")
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if params.Hostname == "" || params.Port <= 0 || params.Username == "" || params.SessionId == "" {
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log.Error("Invalid SSH connection parameters: %v", params)
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return
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}
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client, err := dialAndValidateTailscaleSSH(agent, params)
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client, err := connectToTailscaleSSH(agent, params)
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if err != nil {
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log.Error("Failed to open SSH pty: %s", err)
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return nil, err
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log.Error("Failed to connect to Tailscale SSH for (%s): %s", params.SessionId, err)
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return
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}
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// Everything in the func is related to the SSH session.
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// Each session runs in its own goroutine, allowing concurrency.
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go func() {
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sess, err := client.NewSession()
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if err != nil {
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log.Error("Failed to create new SSH session: %s", err)
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client.Close()
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}
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modes := ssh.TerminalModes{
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ssh.ECHO: 1, // enable echoing
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ssh.TTY_OP_ISPEED: 14400,
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ssh.TTY_OP_OSPEED: 14400,
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}
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if err := sess.RequestPty("xterm-256color", 80, 40, modes); err != nil {
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log.Error("Failed to request PTY: %s", err)
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client.Close()
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}
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ctx := addSession(params.Id, sess)
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go func() {
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for data := range ctx.InputCh {
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if _, err := ctx.Stdin.Write(data); err != nil {
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log.Error("Failed to write to SSH stdin: %s", err)
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return
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}
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log.Debug("Creating SSH session for session ID: %s", params.SessionId)
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sess, err := client.NewSession()
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if err != nil {
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log.Error("Failed to create new SSH session: %s", err)
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client.Close()
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return
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}
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}();
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if err := sess.Shell(); err != nil {
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log.Error("Failed to start shell: %s", err)
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modes := ssh.TerminalModes{
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ssh.ECHO: 1,
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ssh.TTY_OP_ISPEED: 14400,
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ssh.TTY_OP_OSPEED: 14400,
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}
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// Resize event is possible via the control channel later
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err = sess.RequestPty("xterm-256color", 80, 40, modes)
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if err != nil {
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log.Error("Failed to request PTY for (%s): %s", params.SessionId, err)
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return
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}
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ctx, err := registerSessionChans(params.SessionId, sess)
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if err != nil {
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log.Error("Failed to register session channels for (%s): %s", params.SessionId, err)
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client.Close()
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return
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}
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// Input buffer handler
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go func() {
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for data := range ctx.InputCh {
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_, err := ctx.Stdin.Write(data)
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if err != nil {
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log.Error("Failed to write to SSH stdin: %s", err)
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return
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}
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}
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}()
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// This spawns 2 goroutins for stdout and stderr
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dispatchSSHStdout(params.SessionId, ctx.Stdout, ctx.Stderr)
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// Spin up a shell and wait for the pty to terminate
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err = sess.Shell()
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if err != nil {
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log.Error("Failed to start shell for (%s): %s", params.SessionId, err)
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client.Close()
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return
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}
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log.Info("Opened an SSH PTY for %s", params.SessionId)
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sess.Wait()
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sess.Close()
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client.Close()
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}
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log.Info("Successfully opened SSH pty for %s@%s:%d", params.Username, params.Hostname, params.Port)
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go streamSSHOutput(params.Id, ctx.Stdout, os.NewFile(4, "sshOutput"))
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sess.Wait();
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sess.Close();
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log.Info("SSH session %s closed (goSide)", params.Id)
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RemoveSession(params.Id)
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log.Info("SSH session for %s closed", params.SessionId)
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RemoveSession(params.SessionId)
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}()
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return client, nil
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}
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