Merge pull request #159 from uselagoon/terminal-resize

fix: handle terminal resizing correctly

internal/k8s/exec.go

@@ -8,6 +8,7 @@ import (
 	"strconv"
 	"time"
 
+	"github.com/gliderlabs/ssh"
 	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -191,16 +192,18 @@ func (c *Client) getExecutor(ctx context.Context, namespace, deployment,
 // shell, running in a pod inside the deployment.
 func (c *Client) Exec(ctx context.Context, namespace, deployment,
 	container string, command []string, stdio io.ReadWriter, stderr io.Writer,
-	tty bool) error {
+	tty bool, winch <-chan ssh.Window) error {
 	exec, err := c.getExecutor(ctx, namespace, deployment, container, command,
 		stderr, tty)
 	if err != nil {
 		return fmt.Errorf("couldn't get executor: %v", err)
 	}
 	// execute the command
 	return exec.StreamWithContext(ctx, remotecommand.StreamOptions{
-		Stdin:  stdio,
-		Stdout: stdio,
-		Stderr: stderr,
+		Stdin:             stdio,
+		Stdout:            stdio,
+		Stderr:            stderr,
+		Tty:               tty,
+		TerminalSizeQueue: newTermSizeQueue(ctx, winch),
 	})
 }

internal/k8s/termsizequeue.go

@@ -0,0 +1,40 @@
+package k8s
+
+import (
+	"context"
+
+	"github.com/gliderlabs/ssh"
+	"k8s.io/client-go/tools/remotecommand"
+)
+
+type termSizeQueue struct {
+	send chan *remotecommand.TerminalSize
+}
+
+// newTermSizeQueue returns a termSizeQueue which implements the
+// remotecommand.TerminalSizeQueue interface. It starts a goroutine which exits
+// when the given context is done.
+func newTermSizeQueue(ctx context.Context, winch <-chan ssh.Window) *termSizeQueue {
+	tsq := termSizeQueue{
+		send: make(chan *remotecommand.TerminalSize, 1),
+	}
+	go func() {
+		for {
+			select {
+			case <-ctx.Done():
+				close(tsq.send)
+				return
+			case window := <-winch:
+				tsq.send <- &remotecommand.TerminalSize{
+					Width:  uint16(window.Width),
+					Height: uint16(window.Height),
+				}
+			}
+		}
+	}()
+	return &tsq
+}
+
+func (t *termSizeQueue) Next() *remotecommand.TerminalSize {
+	return <-t.send
+}

internal/sshserver/sessionhandler.go

@@ -99,8 +99,8 @@ func sessionHandler(log *zap.Logger, c *k8s.Client, sftp bool) ssh.Handler {
 			}
 			return
 		}
-		// check if a pty was requested
-		_, _, pty := s.Pty()
+		// check if a pty was requested, and get the window size channel
+		_, winch, pty := s.Pty()
 		// extract info passed through the context by the authhandler
 		ctx := s.Context()
 		eid, ok := ctx.Value(environmentIDKey).(int)
@@ -137,7 +137,7 @@ func sessionHandler(log *zap.Logger, c *k8s.Client, sftp bool) ssh.Handler {
 			zap.Strings("command", cmd),
 		)
 		err = c.Exec(s.Context(), s.User(), deployment, container, cmd, s,
-			s.Stderr(), pty)
+			s.Stderr(), pty, winch)
 		if err != nil {
 			log.Warn("couldn't execute command",
 				zap.String("sessionID", sid),