Azure Pipelines Agent Development

Expert assistant for developing the Azure Pipelines Agent, a cross-platform build and release agent written in C# for .NET Core.

Project Context

The Azure Pipelines Agent is a cross-platform agent for Azure DevOps that supports Windows, macOS, and Linux. All development should follow the established patterns and use the provided build tooling.

Project Structure Rules

When working with this codebase:

1. **Source Code Location**: All source code resides in the `src/` directory

2. **Build Scripts**: Use `src/dev.sh` (Linux/macOS) or `src/dev.cmd` (Windows)

3. **Agent Layout**: Built agent outputs to `{root}/{runtime_id}/_layout`

4. **Documentation**: Reference materials in `docs/` directory

Development Workflow

First-Time Setup

When a developer starts working on this project:

1. Clone the repository

2. Navigate to the `src/` directory

3. Run the layout command to create the full agent structure:

- Linux/macOS: `./dev.sh layout`

- Windows: `dev layout`

Standard Development Cycle

Follow this sequence for all changes:

1. **Initial Layout** (first time only): `./dev.sh layout`

2. **Make Changes**: Edit source files as needed

3. **Build**: `./dev.sh build` - compiles and updates agent layout

4. **Test**: `./dev.sh test` - runs unit tests for current platform

5. **Commit**: Standard git workflow

Build Command Structure

**Linux/macOS:**

```bash

./dev.sh {command} [target_framework] [build_config] [runtime_id] [test_filters]

```

**Windows:**

```cmd

dev {command} [target_framework] [build_config] [runtime_id] [test_filters]

```

Available Commands

Use these commands from the `src/` directory:

Technology Stack Details

Core Technologies

Supported Platforms and Runtime IDs

Key Components

Testing Guidelines

Test Types

1. **L0 Tests (Unit Tests)**: `./dev.sh testl0`

2. **L1 Tests (Integration Tests)**: `./dev.sh testl1`

Custom Test Filters

Apply test filters using the 5th parameter:

```bash

./dev.sh test net6.0 Debug osx-arm64 "TestCategory=YourCategory"

```

Testing Best Practices

Debugging

Enable Debug Mode

Run the agent with debug flags:

```bash

./config.sh --debug

./run.sh --debug

```

Debug Environment Variables

Build Configurations

Configuration Types

Package Types

Code Style Requirements

Follow [.NET Foundation coding guidelines](https://github.com/dotnet/corefx/blob/master/Documentation/coding-guidelines/coding-style.md):

1. Use PascalCase for public members

2. Use camelCase for private fields

3. Use meaningful, descriptive names

4. Keep methods focused and small

5. Include XML documentation for public APIs

Common Development Tasks

Adding New Features

1. Create or modify source files in appropriate `src/` subdirectories

2. Add corresponding unit tests in `src/Test/`

3. Build and test: `./dev.sh build && ./dev.sh test`

4. Update documentation if API changes are introduced

Working with Agent Layout

The built agent in `_layout/` can be used for:

To configure and run:

```bash

cd {root}/{runtime_id}/_layout

./config.sh

./run.sh

```

Troubleshooting

Common Build Issues

Best Practices

When working with this codebase:

1. Always run `layout` command on first setup

2. Build before testing to ensure changes are compiled

3. Run tests before committing to catch regressions

4. Use the correct runtime ID for your target platform

5. Follow the standard development flow consistently

6. Keep the agent layout updated with `build` command

Dependencies

The project requires:

Additional Resources