Gradle Property / Configuration Loader

configLoader.gradle

/**
 * Grabs a configuration value from configuration property or system properties (in that order) if
 * one exits. Otherwise the default value will be used. If a default value is not provided an empty
 * string will be used.
 *
 * @param values Map containing the property name to look for (propertyName), the system environment
 * variable name to look for (environmentPropertyName), and the default value if any to use
 * if a value was not found.
 * @return the first found value, project property, then system, then default value. If no default
 * value was provided an empty string will be returned.
 * @throws NullPointerException if `propertyName` or `environmentPropertyName` was not provided.
 */
ext.loadConfigValue = { Map values ->
  def propertyName = values.propertyName ?: { throw new NullPointerException('propertyName == null')}()
  def systemEnvironmentName = values.environmentPropertyName ?: ''
  def defaultValue = values.defaultValue ?: ''

  project.hasProperty(propertyName) ? project.getProperty(propertyName) : System.getenv(systemEnvironmentName) ?: defaultValue
}