git.gradle

import org.gradle.api.DefaultTask
import org.gradle.api.Plugin
import org.gradle.api.Project
import org.gradle.api.tasks.TaskAction
import org.gradle.api.tasks.Input
import org.gradle.api.tasks.OutputFile

apply plugin: GitPropertiesPlugin

class GitPropertiesPlugin implements Plugin<Project> {
    def describe
    def id
    def commitUser
    def commitDate
    def branch
    def buildDate
    def buildUser
    def propsFile

    @Override
    void apply(Project project) {
        project.ext.gitPropertiesPath = "${project.buildDir}/resources/main/git.properties"
        project.task('gitProps', group: 'Build') << {
            this.propsFile = new File(project.ext.gitPropertiesPath)
            project.exec {
                commandLine 'git describe'.split()
                standardOutput = new ByteArrayOutputStream()
                this.describe = { standardOutput.toString().trim() }
                workingDir project.projectDir
            }
            project.exec {
                commandLine 'git rev-parse HEAD'.split()
                standardOutput = new ByteArrayOutputStream()
                this.id = { standardOutput.toString().trim() }
            }
            project.exec {
                commandLine 'git log -1 HEAD --pretty=format:%ae'.split()
                standardOutput = new ByteArrayOutputStream()
                this.commitUser = { standardOutput.toString().trim() }
            }
            project.exec {
                commandLine 'git rev-parse --abbrev-ref HEAD'.split()
                standardOutput = new ByteArrayOutputStream()
                this.branch = { standardOutput.toString().trim() }
            }
            project.exec {
                commandLine 'git log -1 HEAD --pretty=format:%ad'.split()
                standardOutput = new ByteArrayOutputStream()
                this.commitDate = { standardOutput.toString().trim() }
            }
            project.exec {
                commandLine 'date'.split()
                standardOutput = new ByteArrayOutputStream()
                this.buildDate = { standardOutput.toString().trim() }
            }
            project.exec {
                commandLine 'whoami'.split()
                standardOutput = new ByteArrayOutputStream()
                this.buildUser = { standardOutput.toString().trim() }
            }
        }
        project.tasks.gitProps.doLast {
            this.propsFile.parentFile.mkdirs()
            this.propsFile.write(
                "git.commit.id.describe=${describe()}\n" +
                "git.commit.id=${id()}\n" +
                "git.commit.time=${commitDate()}\n" +
                "git.commit.user.name=${commitUser()}\n" +
                "git.branch=${branch()}\n" +
                "git.build.time=${buildDate()}\n" +
                "git.build.user.name=${buildUser()}\n")
        }

        project.tasks.jar.dependsOn project.tasks.gitProps
        project.tasks.gitProps.outputs.file project.ext.gitPropertiesPath
        project.tasks.gitProps.inputs.files project.sourceSets.main.output.classesDir
    }
}