video-download-faas（视频下载 faas）

Video Download FaaS

Download videos asynchronously using yt-dlp in isolated background processes. All downloads are saved as MP4 files.

Overview

This skill manages video downloads as background tasks that:

• Start immediately and return control to the user
• Continue running even if the session disconnects
• Can be monitored for progress
• Can be terminated when needed

When to Use

Use this skill when:

• Downloading large videos that take time
• Processing multiple videos concurrently
• Running downloads on remote/headless systems
• Need to continue working while downloading

Quick Start

Start a Download

scripts/download.sh "https://youtube.com/watch?v=..."

Returns immediately with:

• Session ID
• Process ID (PID)
• Log file location

Check Status

# List all active downloads
scripts/check-status.sh

# Check specific download
scripts/check-status.sh video_dl_1234567890_12345

Kill Download

# Graceful stop
scripts/kill-download.sh video_dl_1234567890_12345

# Force kill
scripts/kill-download.sh video_dl_1234567890_12345 --force

Commands

download.sh

Start a video download in background with MP4 output format.

Usage:

download.sh <URL> [output_directory]

Parameters:

• URL - Video URL to download (required)
• output_directory - Where to save video (optional, default: ~/Downloads)

Output Format:

• Downloads are automatically converted to MP4 format
• Uses best available MP4 video + M4A audio, merged into MP4
• If source isn't MP4, it will be re-encoded to MP4

Returns:

• Session ID for tracking
• PID for process management
• Paths to log and session files

Example:

scripts/download.sh "https://www.youtube.com/watch?v=dQw4w9WgXcQ" /tmp/videos

check-status.sh

Check download progress and status.

Usage:

# List all sessions
check-status.sh

# Check specific session
check-status.sh <session_id>

Returns:

• Process status (running/completed)
• Download progress (if running)
• Downloaded files (if completed)
• Error information (if failed)

kill-download.sh

Terminate a running download.

Usage:

kill-download.sh <session_id> [--force]

Parameters:

• session_id - The session ID from download.sh
• --force - Use SIGKILL instead of SIGTERM

Session Management

Session files are stored in /tmp/ with format:

• video_dl_{timestamp}_{pid}.session - Session metadata
• video_dl_{timestamp}_{pid}.pid - Process ID
• video_dl_{timestamp}_{pid}.log - Download log

Sessions are automatically cleaned up when:

• Download completes successfully
• Process is killed via kill-download.sh

FaaS Integration

For containerized/Firecracker execution:

# Run download in isolated container
./run-in-container.sh scripts/download.sh "URL"

# Check from host
scripts/check-status.sh

Troubleshooting

Download not starting:

• Check yt-dlp is installed: yt-dlp --version
• Verify URL is accessible: curl -I "URL"

Process not found:

• Session may have completed and auto-cleaned
• Check ~/Downloads for finished files

Permission denied:

• Ensure scripts are executable: chmod +x scripts/*.sh

Requirements

• yt-dlp installed and in PATH
• Bash 4.0+
• Write access to /tmp and output directory