maven.gradle

def properties = new Properties()
def propsFile = file("$rootDir/publish.properties")
if (propsFile.exists()) {
    properties.load(propsFile.newInputStream())
}

/*
* 1. findProperty("sonatypeUsername"): use parameter from the command (if attached) so you can run ->
* /gradlew deploy -PsonatypeUsername={yourMavenUsername} -PsonatypePassword={yourMavenPassword}.
* 2. properties["sonatype.user"]: use property defined in publish.properties file in the root directory. If you have that file in the root
* of the project you can run -> ./gradlew deploy
* 3. System.getenv("SONATYPE_PASS"): use global variable defined in the system. No need to create publish.properties file, you can simply
* run -> ./gradlew deploy.
*/
ext.sonatype = [

        url     : properties["sonatype.url"]
                ?: "https://oss.sonatype.org/service/local/staging/deploy/maven2",

        username: findProperty("sonatypeUsername")?.toString()
                ?: properties["sonatype.user"]
                ?: System.getenv("SONATYPE_USERNAME"),

        password: findProperty("sonatypePassword")?.toString()
                ?: properties["sonatype.password"]
                ?: System.getenv("SONATYPE_PASS")
]