private void logException(Exception exp) {
        if (exp.getCause() != null) {
            log.error("%s [%s]", exp.getMessage(), exp.getCause().getMessage());
        } else {
            log.error("%s", exp.getMessage());
        }
    }
Entry point for this plugin. It will set up the helper class and then calls
{@link #executeInternal(ServiceHub)}
which must be implemented by subclass.

@throws MojoExecutionException
@throws MojoFailureException
src/main/java/io/fabric8/maven/docker/AbstractDockerMojo.java