Sandbox Providers

Quick Start

require "ask-sandbox-providers"

# Default: Local (subprocess + rlimits)
result = Ask::Sandbox.provider.call(["ruby", "-e", "puts 1+1"])
result.stdout     # => "2
"
result.exit_code  # => 0

# String commands → shell execution
Ask::Sandbox.provider.call("ls -la | head -5")

# Array commands → execve-style (no shell)
Ask::Sandbox.provider.call(["ruby", "-e", "puts ENV['HOME']"])

Switch Provider

Ask::Sandbox.provider = :docker
Ask::Sandbox.provider = Ask::Sandbox::Docker.new(
  image: "ruby:3.4-alpine",
  memory: "256m",
  network: false
)

Ask::Sandbox.provider = :daytona
Ask::Sandbox.provider = Ask::Sandbox::Daytona.new(
  api_key: ENV["DAYTONA_API_KEY"]
)

Ask::Sandbox.provider = :cloudflare
Ask::Sandbox.provider = Ask::Sandbox::Cloudflare.new(
  worker_url: "https://sandbox-proxy.my-worker.workers.dev",
  auth_token: ENV["CLOUDFLARE_SANDBOX_TOKEN"]
)

`Ask::Sandbox::Result`

Result = Data.define(:stdout, :stderr, :exit_code, :timed_out)
result.success?  # exit_code == 0

Providers

Local (Default)

Process-level isolation via Process.spawn with pgroup: true.

Security measures:

Process group isolation — kills entire tree on timeout
Process.setrlimit: CPU (10s/30s), address space (2GB), processes (50), file size (10MB), FDs (200)
Temp directory via Dir.mktmpdir
Environment sanitization — strips BUNDLE_*, GEM_*, RUBYOPT, RUBYLIB; preserves ASK_*
Output truncated at 100KB per stream

Docker

Full container isolation via the docker CLI.

Constructor:

Docker.new(
  image: "ruby:3.4-alpine",   # Docker image
  memory: "512m",               # Memory limit
  cpus: 1.0,                    # CPU limit
  network: false,               # Block network egress
  read_only: true,              # Read-only rootfs
  cap_drop: "ALL",              # Drop all capabilities
  user: nil,                    # Container default user
  timeout: 30,                  # Default timeout
  remove: true                  # Auto-cleanup
)

Flags passed to docker run:

--read-only — read-only root filesystem
--cap-drop ALL — no Linux capabilities
--security-opt no-new-privileges
--network none — no network egress
--pids-limit 100
--memory, --cpus — resource limits

Daytona

Remote sandbox via the official daytona gem. The gem is loaded lazily — install it only if you use this provider.

Daytona.new(
  api_key: nil,       # Falls back to ENV["DAYTONA_API_KEY"] or Ask::Auth.lookup
  server_url: nil,    # Defaults to Daytona SDK default
  image: nil,         # Sandbox image (default: "ruby:3.4")
  timeout: 120        # Sandbox boot can take time
)

Cloudflare

Edge sandbox via a user-deployed proxy Worker wrapping @cloudflare/sandbox.

Cloudflare.new(
  worker_url: nil,    # Falls back to ENV["CLOUDFLARE_SANDBOX_WORKER_URL"]
  auth_token: nil,    # Falls back to ENV["CLOUDFLARE_SANDBOX_AUTH_TOKEN"]
  timeout: 60
)

Requirements:

Deploy a proxy Worker that wraps @cloudflare/sandbox
Set CLOUDFLARE_SANDBOX_WORKER_URL or pass worker_url: