Add DevTunnel CLI DevContainer Feature

[Copilot]

Scaffolds a complete DevContainer Feature for installing the Microsoft DevTunnel CLI, enabling developers to create secure tunnels to localhost for webhook testing, remote collaboration, and device testing.

Implementation

Feature Core (src/devtunnel/)

• devcontainer-feature.json - Feature metadata with version option
• install.sh - Multi-architecture installer (amd64/arm64) with 3-attempt retry logic
• README.md / NOTES.md - Feature documentation and usage examples

CI/CD (.github/workflows/)

• ci.yml - JSON/shell validation + feature testing
• release.yml - GHCR publishing workflow

Documentation

• Root README.md - Project overview and quick start
• CONTRIBUTING.md - Contribution guidelines
• examples/basic/ - Working example configuration

Usage

{
  "features": {
    "ghcr.io/abeckDev/devtunnel-devcontainer-feature/devtunnel:1": {}
  }
}

Then in container:

devtunnel user login
devtunnel host -p 3000 --allow-anonymous

Follows DevContainer Features spec, modeled after the Azure CLI feature implementation.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• aka.ms
  • Triggering command: curl -sL REDACTED -I (dns block)
  • Triggering command: curl -sSL REDACTED -o /usr/local/bin/devtunnel (dns block)
• learn.microsoft.com
  • Triggering command: curl -s REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

I want to create a Devcontainer Feature for the Devtunnel CLI. Prepare the scaffold as good as possible and add documentation.

Devtunnel: https://learn.microsoft.com/en-us/azure/developer/dev-tunnels/overview

Sample: https://github.com/devcontainers/features/tree/main/src/azure-cli

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