- Understand caching
- Explore remote build caching
****

[[part6_begin]]
== Step 0. Before you Begin

1. You initialized your Java app in <<part1_gradle_init.adoc#part1_begin,part 1>>.
2. You ran several tasks in <<part2_gradle_tasks#part2_begin,part 2>>.
3. You learned about dependency management in <<part3_gradle_dep_man#part3_begin,part 3>>.
4. You applied a plugin to your app in <<part4_gradle_plugins#part4_begin,part 4>>.

        mavenMetadataFactory.create(id, []) as AbstractMutableModuleComponentResolveMetadata
    }

    def "defines configurations for maven scopes and several usage buckets"() {
        def id = DefaultModuleComponentIdentifier.newId(DefaultModuleIdentifier.newId("group", "module"), "version")
        def metadata = mavenMetadataFactory.create(id, [])

        expect:

    // This test simulates a long running Zinc compiler setup by running code similar to ZincScalaCompilerFactory through the worker API.
    // if many workers wait for the same exclusive lock, a worker does not time out because several others get the lock before
    def "worker not timeout"() {
        given:
        def gradleUserHome = file("home").absoluteFile
        buildFile << """
            task doWorkInWorker(type: WorkerTask) {

	// (1) it is the last waiter in the queue, or (2) it waited for less than 1 ms,
	// it switches mutex back to normal operation mode.
	//
	// Normal mode has considerably better performance as a goroutine can acquire
	// a mutex several times in a row even if there are blocked waiters.
	// Starvation mode is important to prevent pathological cases of tail latency.
	starvationThresholdNs = 1e6
)

// Lock locks m.

	// podAttachAndMountTimeout is the maximum amount of time the
	// WaitForAttachAndMount call will wait for all volumes in the specified pod
	// to be attached and mounted. Even though cloud operations can take several
	// minutes to complete, we set the timeout to 2 minutes because kubelet
	// will retry in the next sync iteration. This frees the associated
	// goroutine of the pod to process newer updates if needed (e.g., a delete

// analysis of that package will be available during later analysis of P.
// Facts are analogous to type export data in a build system:
// just as export data enables separate compilation of several passes,
// facts enable "separate analysis".
//
// Each pass (a, p) starts with the set of facts produced by the
// same analyzer a applied to the packages directly imported by p.

        if (matches.size() > 1) {
            // there's an ambiguity, but we may have several variants matching the requested capabilities.
            // Here we're going to check if in the candidates, there's a single one _strictly_ matching the requested capabilities.

        then:
        conf1State.resolveArtifacts().artifacts.size() == 3
        conf2State.resolveArtifacts().artifacts.size() == 1
    }

    def "can add artifact to several configurations"() {
        def artifact = artifactName()
        def file = new File("artifact.zip")

        given:
        def conf1 = consumable("conf1")
        def conf2 = consumable("conf2")

        The only attribute distinguishing these variants is 'color'. Add this attribute to the consumer's configuration to resolve the ambiguity:

[[sec:convention_plugins]]
== Share logic using convention plugins

Gradle's recommended way of organizing build logic is to use its plugin system.

We can write a plugin that encapsulates the build logic common to several subprojects in a project.
This kind of plugin is called a *convention plugin*.