portainer/app/docker/rest/systemEndpoint.js

angular.module('portainer.docker')
.factory('SystemEndpoint', ['$resource', 'API_ENDPOINT_ENDPOINTS',
  function SystemEndpointFactory($resource, API_ENDPOINT_ENDPOINTS) {
  'use strict';
  return $resource(API_ENDPOINT_ENDPOINTS + '/:endpointId/docker/:action/:subAction', {
    name: '@name'
  },
  {
    ping: {
      method: 'GET', params: { action: '_ping', endpointId: '@endpointId' }, timeout: 10000
    }
  });
}]);