Spring Boot: Step to register bootrun as gradle task

When we use Spring Boot, bootrun is automatically registered as a Gradle task. I followed its steps, how it is registered

The codes I posted here is the code in the master branch of each repository on 2018-05-20.

The task is added when the plugin is added

bootrun can be used when the Spring Boot is added into build.gradle.

When loading Spring Boot plugin with apply plugin description, SpringBootPlugin‘s execute is executed. And JavaPluginAction plugin is added in it.

private void registerPluginActions(Project project, Configuration bootArchives) {
SinglePublishedArtifact singlePublishedArtifact = new SinglePublishedArtifact(
bootArchives.getArtifacts());
List<PluginApplicationAction> actions = Arrays.asList(
new JavaPluginAction(singlePublishedArtifact),
new WarPluginAction(singlePublishedArtifact),
new MavenPluginAction(bootArchives.getUploadTaskName()),
new DependencyManagementPluginAction(), new ApplicationPluginAction(),
new KotlinPluginAction());
for (PluginApplicationAction action : actions) {
Class<? extends Plugin<? extends Project>> pluginClass = action
.getPluginClass();
if (pluginClass != null) {
project.getPlugins().withType(pluginClass,
(plugin) -> action.execute(project));
}
}
}

private void registerPluginActions(Project project, Configuration bootArchives) {

SinglePublishedArtifact singlePublishedArtifact = new SinglePublishedArtifact(

bootArchives.getArtifacts());

List<PluginApplicationAction> actions = Arrays.asList(

new JavaPluginAction(singlePublishedArtifact),

new WarPluginAction(singlePublishedArtifact),

new MavenPluginAction(bootArchives.getUploadTaskName()),

new DependencyManagementPluginAction(), new ApplicationPluginAction(),

new KotlinPluginAction());

for (PluginApplicationAction action : actions) {

Class<? extends Plugin<? extends Project>> pluginClass = action

.getPluginClass();

if (pluginClass != null) {

project.getPlugins().withType(pluginClass,

(plugin) -> action.execute(project));

}

There, KotlinPluginAction will add Kotlin Gradle plugin.

JavaPluginAction is loaded as plugin, so the execute function in it will be executed. JavaPluginAction implements PluginApplicationAction interface. PluginApplicationAction is the derived interface from Action<Project>, which has a object with one additional method to Action<Project>.

@Override
public void execute(Project project) {
disableJarTask(project);
configureBuildTask(project);
BootJar bootJar = configureBootJarTask(project);
configureArtifactPublication(bootJar);
configureBootRunTask(project);
configureUtf8Encoding(project);
configureParametersCompilerArg(project);
configureAdditionalMetadataLocations(project);
}

@Override

public void execute(Project project) {

disableJarTask(project);

configureBuildTask(project);

BootJar bootJar = configureBootJarTask(project);

configureArtifactPublication(bootJar);

configureBootRunTask(project);

configureUtf8Encoding(project);

configureParametersCompilerArg(project);

configureAdditionalMetadataLocations(project);

}

この中の configureBootRunTask でタスク bootrun が追加されます。

private void configureBootRunTask(Project project) {
JavaPluginConvention javaConvention = project.getConvention()
.getPlugin(JavaPluginConvention.class);
BootRun run = project.getTasks().create("bootRun", BootRun.class);
run.setDescription("Runs this project as a Spring Boot application.");
run.setGroup(ApplicationPlugin.APPLICATION_GROUP);
run.classpath(javaConvention.getSourceSets()
.findByName(SourceSet.MAIN_SOURCE_SET_NAME).getRuntimeClasspath());
run.getConventionMapping().map("jvmArgs", () -> {
if (project.hasProperty("applicationDefaultJvmArgs")) {
return project.property("applicationDefaultJvmArgs");
}
return Collections.emptyList();
});
run.conventionMapping("main",
new MainClassConvention(project, run::getClasspath));
}

private void configureBootRunTask(Project project) {

JavaPluginConvention javaConvention = project.getConvention()

.getPlugin(JavaPluginConvention.class);

BootRun run = project.getTasks().create("bootRun", BootRun.class);

run.setDescription("Runs this project as a Spring Boot application.");

run.setGroup(ApplicationPlugin.APPLICATION_GROUP);

run.classpath(javaConvention.getSourceSets()

.findByName(SourceSet.MAIN_SOURCE_SET_NAME).getRuntimeClasspath());

run.getConventionMapping().map("jvmArgs", () -> {

if (project.hasProperty("applicationDefaultJvmArgs")) {

return project.property("applicationDefaultJvmArgs");

}

return Collections.emptyList();

});

run.conventionMapping("main",

new MainClassConvention(project, run::getClasspath));

}

What is BootRun?

bootrun is customized gradle run for Spring Boot, which becomes available by apply plugin: 'application'. BootRun is derived from JavaExec, and not so different from JavaExec.

/**
* Custom {@link JavaExec} task for running a Spring Boot application.
*
* @author Andy Wilkinson
* @since 2.0.0
*/
public class BootRun extends JavaExec {
/**
* Adds the {@link SourceDirectorySet#getSrcDirs() source directories} of the given
* {@code sourceSet's} {@link SourceSet#getResources() resources} to the start of the
* classpath in place of the {@link SourceSet#getOutput output's}
* {@link SourceSetOutput#getResourcesDir() resources directory}.
* @param sourceSet the source set
*/
public void sourceResources(SourceSet sourceSet) {
setClasspath(getProject()
.files(sourceSet.getResources().getSrcDirs(), getClasspath())
.filter((file) -> !file.equals(sourceSet.getOutput().getResourcesDir())));
}
@Override
public void exec() {
if (System.console() != null) {
// Record that the console is available here for AnsiOutput to detect later
this.getEnvironment().put("spring.output.ansi.console-available", true);
}
super.exec();
}
}