Babarot Gh Infra Gh Infra

VHS Tape Authoring

Use this skill to create or edit VHS tape files and their supporting setup scripts for gh-infra demos.

When To Use

• Adding a new demo for a gh-infra feature
• Editing an existing tape's scenario or timing
• Setting up mock data for a new demo
• Understanding how mock-gh works

Tape File Structure

Every .tape follows this pattern:

# 1. Output targets
Output demo-<name>.gif
Output demo-<name>.mp4

# 2. Theme and layout
Set Theme { ... }
Set Shell "bash"
Set FontSize 20
Set Width 1400
Set Height 900
Set Padding 20
Set WindowBar ""
Set TypingSpeed 50ms

# 3. Hidden setup
Hide
Type "source /data/setup-<name>.sh"
Enter
Sleep 2s
Type "clear"
Enter
Sleep 500ms
Show

# 4. Visible demo sequence
Sleep 700ms
Type "gh infra ..."
Enter
Sleep 3s
# ... more actions ...
Sleep 2s

Themes

Two themes are available. Copy from an existing tape:

VHS Commands Reference

Timing Guidelines

Setup Script Pattern

Each tape has a corresponding setup-<name>.sh:

#!/usr/bin/env bash
set -euo pipefail

# 1. Install gh-infra binary
cp /data/.gh-infra /usr/local/bin/gh-infra
chmod +x /usr/local/bin/gh-infra

# 2. Create gh wrapper (routes "gh infra" to real binary, rest to mock)
cat > /usr/local/bin/gh << 'WRAPPER'
#!/usr/bin/env bash
if [[ "$1" == "infra" ]]; then
  shift
  exec /usr/local/bin/gh-infra "$@"
fi
exec /data/mock-gh "$@"
WRAPPER
chmod +x /usr/local/bin/gh

# 3. Populate mock data
export MOCK_DIR=/tmp/mock-data
mkdir -p "$MOCK_DIR/<owner>/<repo>"
cat > "$MOCK_DIR/<owner>/<repo>/view.json" << 'JSON'
{ ... }
JSON

# 4. Create demo working directory and manifests
mkdir -p /tmp/demo
cat > /tmp/demo/<manifest>.yaml << 'YAML'
...
YAML

# 5. Set prompt
export PS1='$ '

The gh wrapper is the key mechanism:

• gh infra ... → real gh-infra binary (spinners, diffs, colors are genuine)
• gh repo view ..., gh api ... etc. → mock-gh returns prepared data

mock-gh Data Layout

mock-gh is data-driven and scenario-agnostic. It reads from $MOCK_DIR:

$MOCK_DIR/{owner}/{repo}/
  view.json                       # gh repo view --json response
  commit-settings.json            # squash/merge commit title/message (optional)
  contents/{path}                 # raw file content (base64-encoded on the fly)

Supported mock responses

All mock responses include a random 200-500ms delay to simulate network latency.

Checklist: Adding a New Demo

1. Check resource headroom: Adding a tape increases parallel resource demand. Count existing tapes (ls docs/tapes/*.tape | wc -l) and multiply by per-container memory (--memory in vhs.sh). If the total approaches or exceeds Docker Desktop's memory allocation, warn the user to either increase Docker Desktop memory (recommended: 16 GB) or consider reducing per-container resources. See the vhs-demo skill for details.

2. Create the tape: docs/tapes/demo-<name>.tape

   • Copy theme/layout from an existing tape
   • Set Output demo-<name>.gif and Output demo-<name>.mp4
   • Script the demo sequence

3. Create the setup script: docs/tapes/setup-<name>.sh

   • Make it executable: chmod +x
   • Populate $MOCK_DIR with the GitHub state the demo needs
   • Create manifest YAML in /tmp/demo/

4. Update Makefile: Add the new GIF to the cp line in the demo target:

   @cp docs/tapes/demo-<name>.gif docs/public/ 2>/dev/null || true
   

5. Test locally: Run make demo or test the single tape:

   docker run --rm -v docs/tapes:/data -w /data gh-infra-vhs demo-<name>.tape
   

6. Verify output: Check that both .mp4 and .gif are non-zero size

Tips

• The Hide/Show block is critical. Viewers should never see the setup phase.
• Keep demos focused on one feature. Aim for under 30 seconds of visible recording.
• If mock-gh doesn't support an API your feature needs, extend mock-gh with a new pattern-match block.
• Type speed is global (TypingSpeed 50ms). For dramatic pauses, use Sleep between Type and Enter.

Source: babarot/gh-infra — distributed by TomeVault.