cmd/tsconnect: add error callback for SSH sessions

We were just logging them to the console, which is useful for debugging,
but we may want to show them in the UI too.

Updates tailscale/corp#6939

Signed-off-by: Mihai Parparita <mihai@tailscale.com>

cmd/tsconnect/src/app/ssh.tsx

@@ -46,7 +46,7 @@ function SSHSession({
   const ref = useRef<HTMLDivElement>(null)
   useEffect(() => {
     if (ref.current) {
-      runSSHSession(ref.current, def, ipn, onDone)
+      runSSHSession(ref.current, def, ipn, onDone, (err) => console.error(err))
     }
   }, [ref])
 

cmd/tsconnect/src/lib/ssh.ts

@@ -14,6 +14,7 @@ export function runSSHSession(
   def: SSHSessionDef,
   ipn: IPN,
   onDone: () => void,
+  onError?: (err: string) => void,
   terminalOptions?: ITerminalOptions
 ) {
   const parentWindow = termContainerNode.ownerDocument.defaultView ?? window
@@ -48,7 +49,7 @@ export function runSSHSession(
       term.write(input)
     },
     writeErrorFn(err) {
-      console.error(err)
+      onError?.(err)
       term.write(err)
     },
     setReadFn(hook) {