From 31416dbf13a74d17e83afae6594c0a931243cb64 Mon Sep 17 00:00:00 2001
From: Jan Baraniewski <dev@baraniewski.com>
Date: Tue, 26 Nov 2024 08:33:42 +0100
Subject: [PATCH] Add ssh keep alive to ssh tunnel to workspace

---
 cmd/ssh.go | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/cmd/ssh.go b/cmd/ssh.go
index f95da43f2..7a8ecd46d 100644
--- a/cmd/ssh.go
+++ b/cmd/ssh.go
@@ -434,6 +434,8 @@ func (cmd *SSHCmd) startTunnel(ctx context.Context, devPodConfig *config.Config,
 	// Traffic is coming in from the outside, we need to forward it to the container
 	if cmd.Proxy || cmd.Stdio {
 		if cmd.Proxy {
+			go startSSHKeepAlive(ctx, containerClient, log)
+
 			go func() {
 				if err := cmd.startRunnerServices(ctx, devPodConfig, containerClient, log); err != nil {
 					log.Error(err)
@@ -451,6 +453,7 @@ func (cmd *SSHCmd) startTunnel(ctx context.Context, devPodConfig *config.Config,
 		!cmd.Proxy && cmd.AgentForwarding &&
 			devPodConfig.ContextOption(config.ContextOptionSSHAgentForwarding) == "true",
 		func(ctx context.Context, stdin io.Reader, stdout io.Writer, stderr io.Writer) error {
+			go startSSHKeepAlive(ctx, containerClient, log)
 			return devssh.Run(ctx, containerClient, command, stdin, stdout, stderr, envVars)
 		},
 		writer,
@@ -659,3 +662,21 @@ func preparePipes() (io.Reader, io.WriteCloser, io.Reader, io.WriteCloser, error
 
 	return stdoutReader, stdoutWriter, stdinReader, stdinWriter, nil
 }
+
+func startSSHKeepAlive(ctx context.Context, client *ssh.Client, log log.Logger) {
+	ticker := time.NewTicker(55 * time.Second)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			log.Infof("SSH keepalive routine stopped: %v", ctx.Err())
+			return
+		case <-ticker.C:
+			_, _, err := client.SendRequest("keepalive@openssh.com", true, nil)
+			if err != nil {
+				log.Errorf("Failed to send keepalive: %w", err)
+			}
+		}
+	}
+}