BuildGraph is a script-based build automation system that features graphs of building blocks common to Unreal Engine 4 (UE4) projects.
BuildGraph integrates with UnrealBuildTool, AutomationTool, and the editor, and can be extended and customized for your projects.
BuildGraph scripts are written in XML, specifying a graph of user-defined nodes with
dependencies between them. Each node consists of tasks executed in sequence to produce some sort of output (e.g., compile
this project, then cook, run this test, and so on). When asked to build a target (that is, a node or named output) BuildGraph
will execute all of the nodes in the graph required to make that happen.
Unlike other build tools, BuildGraph is designed as a hybrid between a makefile-like scripting language and a build farm
configuration script. It enables annotations for the type of machine that steps are supposed to be executed on, providing a
list of recipients for failure notifications if a step fails, and groups nodes that should only be executed after an explicit
user trigger. It also tracks the creation of output files from task execution in a way that lends to graph execution being
distributed across a farm of machines (with nodes running in parallel where possible), and intermediate artifacts being
transferred to and from a network share automatically.
Epic uses BuildGraph to prepare the UE4 binary release, package samples for the marketplace, and implement pipelines for our
own games (among other things). Several example BuildGraph scripts are provided in the
[UE4Root]/Engine/Build/Graph/Examples directory, and the script for creating a binary UE4 distribution can be found at
Opening a script with Visual Studio will use the schema located at
[UE4Root]Engine/Build/Graph/Schema.xsd to provide rich
tooltips, validation, and Intellisense features while editing.