Terminal

The terminal is the core feature of Learning UI, providing an interactive shell environment for hands-on learning.

Features

Multiple Terminal Tabs

Users can open multiple terminal tabs, all connected to the same shell container but running independent bash sessions.

Keyboard Shortcuts:

• Ctrl+Shift+T: New tab
• Ctrl+Shift+W: Close current tab
• Ctrl+Tab: Next tab
• Double-click tab to rename

Code Block Integration

Code blocks in the instructions panel have interactive buttons:

• Copy: Copy code to clipboard
• Run: Execute directly in the active terminal

This allows users to quickly run commands without manual copy-paste.

Resizable Panels

The interface features a draggable divider between the instructions panel and terminal panel. Users can resize according to their preference.

Configuration

Enable/Disable Terminal Tab

You can hide the terminal tab if your scenario uses only the editor or custom services:

terminal:
  enabled: true  # Set to false to hide terminal tab

Shell Container

The terminal connects to the shell container in the StatefulSet. Configure it in your values:

shell:
  image:
    repository: debian
    tag: bookworm
    pullPolicy: IfNotPresent

  command: ["sleep"]
  args: ["infinity"]

  resources:
    requests:
      memory: "256Mi"
      cpu: "100m"
    limits:
      memory: "512Mi"
      cpu: "500m"

How It Works

1. The UI pod runs a Go server that handles WebSocket connections
2. When a terminal tab is opened, a WebSocket connection is established to /ws/terminal
3. The server uses kubectl exec to spawn a bash session in the shell pod
4. Input/output is streamed between the browser and the shell container via the WebSocket

Technical Details

Browser (xterm.js)
    ↕ WebSocket
UI Pod (Go Server)
    ↕ kubectl exec -it
Shell Pod (bash)

The terminal uses xterm.js for terminal emulation in the browser, providing a full-featured terminal experience including:

• ANSI color support
• Cursor positioning
• Line editing (readline)
• Terminal resizing

Troubleshooting

Terminal not connecting

1. Check that the shell pod is running:

   kubectl get pods -l app.kubernetes.io/component=shell

2. Verify the UI pod has RBAC permissions:

   kubectl get role,rolebinding -l app.kubernetes.io/instance=<release-name>

3. Check UI pod logs:

   kubectl logs -l app.kubernetes.io/component=ui

Terminal disconnects frequently

This may be due to network timeouts. Check your ingress configuration for WebSocket timeout settings:

ingress:
  annotations:
    nginx.ingress.kubernetes.io/proxy-read-timeout: "3600"
    nginx.ingress.kubernetes.io/proxy-send-timeout: "3600"