build.gradle

def fetchPassword(identifier) {
    if (!Os.isFamily(Os.FAMILY_MAC)) {
        println "Not on macOS, falling back to using keystore password from Environment"
        return props.getProperty(identifier)
    }

    def keychainLabel = "${identifier}"
    println "Fetching keychain password with label '${keychainLabel}"

    def stdout = new ByteArrayOutputStream()
    def stderr = new ByteArrayOutputStream()
    def keychainExec = exec {
        commandLine 'security', '-q', 'find-generic-password', '-gl', "${keychainLabel}"
        standardOutput = stdout
        errorOutput = stderr
        ignoreExitValue true
    }

    if (keychainExec.exitValue != 0) {
        println stdout.toString()
        println stderr.toString()
        return
    }
    (stderr.toString().trim() =~ /password: "(.*)"/)[0][1]
}