Table of Contents

Introduction

Atom is a build automation framework for .NET that lets you define your entire build pipeline in C#. Instead of maintaining separate YAML or script files, you write strongly-typed build logic alongside your application code, gaining full IDE support — IntelliSense, refactoring, and step-through debugging.

Key Concepts

Concept Description
Build Definition A C# class that declares your targets, parameters, and build configuration.
Target A named unit of work (compile, test, pack, deploy, etc.) with optional dependencies on other targets.
Parameter A value that can be supplied via the command line, environment variable, appsettings.json, or a secrets provider.
Module A NuGet package that adds reusable targets, parameters, or service registrations to your build.
Workflow An optional layer that maps targets to CI/CD jobs and generates platform-specific YAML (GitHub Actions, Azure DevOps).

Package Overview

Atom is split into several NuGet packages so you only pull in what you need:

Package Purpose
DecSm.Atom.Build Core framework — build definitions, targets, parameters, hosting.
DecSm.Atom.Workflows Workflow definitions, triggers, and YAML generation.
DecSm.Atom.FileSystem IAtomFileSystem, RootedPath, path providers, and file transformations.
DecSm.Atom.Process IProcessRunner for executing external tools.
DecSm.Atom.SemanticVersion Semantic versioning utilities.
DecSm.Atom.Module.* First-party modules (Dotnet, GitVersion, AzureKeyVault, etc.).
DecSm.Atom.Tool The atom .NET global tool for running builds from the command line.

How It Works

  1. You create a C# project (or a single .cs file) that references the Atom packages.
  2. You define a class decorated with [BuildDefinition] that inherits from BuildDefinition (or WorkflowBuildDefinition if you need CI/CD generation).
  3. Inside that class you declare targets — lambda-based definitions that describe what to execute, their dependencies, required parameters, and produced artifacts.
  4. You run the build with dotnet run -- <TargetName> (or via the atom global tool).
  5. If you use WorkflowBuildDefinition, running the GenerateWorkflowFiles target emits platform-specific YAML that invokes your same build on CI.

Next Steps

→ Your First Build

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