[[sec:basic_usage]]
== Using an init script

Initialization scripts, also called _init scripts_, are similar to other scripts in Gradle.
Initialization scripts run before the build starts.

They are useful for various purposes:

* Setting up enterprise-wide configurations (e.g., custom plugin locations)
* Configuring properties based on the environment (e.g., developer's machine vs. CI server)

     *
     * Gradle runtime.
     */
    ClassLoaderScope getBaseClassLoaderScope();

    /**
     * The scope for this settings object.
     *
     * Gradle runtime + this object's script's additions.
     */
    ClassLoaderScope getClassLoaderScope();

    ServiceRegistry getServices();

    @Override
    BuildCacheConfigurationInternal getBuildCache();

    @Override

create in the script's temporary file system before it starts executing.

As an example, run_hello.txt says:

	# hello world
	go run hello.go
	stderr 'hello world'
	! stdout .

	-- hello.go --
	package main
	func main() { println("hello world") }

Each script runs in a fresh temporary work directory tree, available to scripts as $WORK.

====
include::sample[dir="snippets/tutorial/groovy/groovy",files="build.gradle[tags=closureDelegates]"]
====

[[script-default-imports]]
== Default imports

To make build scripts more concise, Gradle automatically adds a set of import statements to scripts.

As a result, instead of writing `throw new org.gradle.api.tasks.StopExecutionException()`, you can write `throw new StopExecutionException()` instead.

        when:
        run 'help'

        then:
        def scripts = scriptDetails()
        scripts.size() == 3
        hasScript("settings", scripts)
        hasScript(":core", scripts)
        hasScript(":module1", scripts)
        eachScriptIsUnique(scripts)
        getCompileBuildFileOperationsCount() == 4 // classpath + body for settings and for the 2 identical scripts
    }

import org.gradle.api.internal.project.ProjectInternal;
import org.gradle.groovy.scripts.BasicScript;
import org.gradle.groovy.scripts.ScriptCompiler;
import org.gradle.groovy.scripts.ScriptCompilerFactory;
import org.gradle.groovy.scripts.ScriptRunner;
import org.gradle.groovy.scripts.ScriptSource;
import org.gradle.groovy.scripts.internal.BuildScriptData;
import org.gradle.groovy.scripts.internal.CompileOperation;
import org.gradle.internal.Actions;

	for i := range reg {
		reg[i] = Region{language.Region(i + 1)}
	}
	return reg
}

// Scripts returns the list of supported scripts. As all scripts are in a
// consecutive range, it simply returns a slice of numbers in increasing order.
// The "undefined" script is not returned.
func (s allSubtags) Scripts() []Script {
	scr := make([]Script, language.NumScripts)
	for i := range scr {
		scr[i] = Script{language.Script(i + 1)}

                }
            }

            @Override
            public BuildOperationDescriptor.Builder description() {
                return BuildOperationDescriptor.displayName("Run init scripts").progressDisplayName("Running init scripts");
            }
        });
    }

*Multi-project* builds include *one root project* and *any number of subprojects*.

=== Build Scripts

*Build scripts* detail to Gradle what steps to take to build the project.

Each project can include one or more build scripts.

=== Dependency Management

*Dependency management* is an automated technique for declaring and resolving external resources required by a project.

    @Rule
    HttpServer server = new HttpServer()

    String scriptUrl
    TestFile scriptFile
    String scriptName = "remote-script.gradle"
    def configurationCache

    def setup() {
        server.start()

        scriptUrl = "${server.uri}/${scriptName}"
        scriptFile = file("remote-script.gradle") << """
            println 'loaded remote script'