Dalec VS Code Extension

VS Code extension for authoring and debugging Dalec specs.

[!WARNING] Early Development: This extension is not production ready yet and may change significantly.

Features

• 🔍 Auto-detects Dalec spec files (YAML with #syntax=... header)
• ✨ Schema-powered completions, hover, and validation via Red Hat YAML extension
• 🐛 BuildKit debugging support with dalec-buildx debug type
• ▶️ CodeLens actions for quick "Debug" and "Build" commands
• 🎯 Queries available targets from the Dalec frontend via docker buildx build --call targets
• 📁 Smart context handling—only prompts when specs reference build contexts

Quick Start

1. Install the extension (via .vsix or Extension Manager)
2. Open a Dalec spec (any .yml/.yaml file starting with #syntax=...)
3. Run your first build using CodeLens or Command Palette
4. View results in the integrated terminal

Commands

All commands are available via the Command Palette (Cmd/Ctrl + Shift + P):

Screenshots

Command Palette (Cmd/Ctrl + Shift + P)

Right-click Context Menu

Dalec: Build Current Spec

Builds the currently opened Dalec spec using docker buildx build.

Requirements

• File must be a valid Dalec YAML spec (starts with #syntax=...)
• Docker with Buildx must be installed and running

How to use

1. Open a Dalec spec file
2. Either:
   • Click the "Dalec: Build" CodeLens at the top of the file, or
   • Open Command Palette (Cmd/Ctrl + Shift + P) → Dalec: Build Current Spec
3. Select a target when prompted (targets are queried from the Dalec frontend via docker buildx build --call targets)
4. Provide build context path if prompted (only when spec uses context sources)

Output

• Build runs in the integrated terminal
• Errors and logs appear in terminal output

Dalec: Debug Current Spec

Launches a BuildKit debug session for the current spec.

Requirements

• Same as Build, plus:
• Set DALEC_ENABLE_DEBUG=1 environment variable before launching VS Code

How to use

1. Open a Dalec spec file
2. Either:
   • Click the "Dalec: Debug" CodeLens, or
   • Open Command Palette → Dalec: Build Current Spec (with debug environment enabled)
3. Select a target and provide context if prompted
4. Debug session starts with breakpoint support

Dalec: Rerun Last Action

Re-executes the previous build or debug action with the same target, spec file, and context settings.

How to use

1. After running a build or debug command at least once
2. Open Command Palette (Cmd/Ctrl + Shift + P) → Dalec: Rerun Last Action
3. The previous action is re-executed with the same parameters

Note: This is useful for quick iteration—change your spec and immediately re-run without re-selecting the target.

Typical Workflow

┌─────────────────────────────────────────────────┐
│  1. Open/create a Dalec YAML spec               │
│                  ↓                              │
│  2. Edit your spec (completions & validation)   │
│                  ↓                              │
│  3. Run "Dalec: Build Spec"                     │
│                  ↓                              │
│  4. Fix any build errors                        │
│                  ↓                              │
│  5. Re-run build → iterate until success        │
└─────────────────────────────────────────────────┘

Example scenarios:

Supported Files

The extension activates for YAML files that match:

#syntax=ghcr.io/project-dalec/dalec/frontend:latest
# or
# syntax=ghcr.io/azure/dalec/frontend:latest

Files without this header are not recognized as Dalec specs.

Installation

For development:

cd dalec-vscode-extension
npm install
npm run compile
code --extensionDevelopmentPath=$(pwd)

For testing:

1. Build with npx vsce package
2. Install .vsix via VS Code Extension Manager

Debug Configuration

Add to .vscode/launch.json:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Dalec: Buildx Debug",
      "type": "dalec-buildx",
      "request": "launch",
      "target": "frontend",
      "specFile": "${file}",
      "context": "${workspaceFolder}"
    }
  ]
}

Requirements

• Docker with Buildx installed
• Red Hat YAML extension (auto-prompted)

Troubleshooting

👉 For more about Dalec, see the Dalec documentation!