service.js

var AWS = require('./core');
var Api = require('./model/api');
var regionConfig = require('./region_config');

var inherit = AWS.util.inherit;
var clientCount = 0;
var region_utils = require('./region/utils');

/**
 * The service class representing an AWS service.
 *
 * @class_abstract This class is an abstract class.
 *
 * @!attribute apiVersions
 *   @return [Array<String>] the list of API versions supported by this service.
 *   @readonly
 */
AWS.Service = inherit({
  /**
   * Create a new service object with a configuration object
   *
   * @param config [map] a map of configuration options
   */
  constructor: function Service(config) {
    if (!this.loadServiceClass) {
      throw AWS.util.error(new Error(),
        'Service must be constructed with `new\' operator');
    }

    if (config) {
      if (config.region) {
        var region = config.region;
        if (region_utils.isFipsRegion(region)) {
          config.region = region_utils.getRealRegion(region);
          config.useFipsEndpoint = true;
        }
        if (region_utils.isGlobalRegion(region)) {
          config.region = region_utils.getRealRegion(region);
        }
      }
      if (typeof config.useDualstack === 'boolean'
        && typeof config.useDualstackEndpoint !== 'boolean') {
        config.useDualstackEndpoint = config.useDualstack;
      }
    }

    var ServiceClass = this.loadServiceClass(config || {});
    if (ServiceClass) {
      var originalConfig = AWS.util.copy(config);
      var svc = new ServiceClass(config);
      Object.defineProperty(svc, '_originalConfig', {
        get: function() { return originalConfig; },
        enumerable: false,
        configurable: true
      });
      svc._clientId = ++clientCount;
      return svc;
    }
    this.initialize(config);
  },

  /**
   * @api private
   */
  initialize: function initialize(config) {
    var svcConfig = AWS.config[this.serviceIdentifier];
    this.config = new AWS.Config(AWS.config);
    if (svcConfig) this.config.update(svcConfig, true);
    if (config) this.config.update(config, true);

    this.validateService();
    if (!this.config.endpoint) regionConfig.configureEndpoint(this);

    this.config.endpoint = this.endpointFromTemplate(this.config.endpoint);
    this.setEndpoint(this.config.endpoint);
    //enable attaching listeners to service client
    AWS.SequentialExecutor.call(this);
    AWS.Service.addDefaultMonitoringListeners(this);
    if ((this.config.clientSideMonitoring || AWS.Service._clientSideMonitoring) && this.publisher) {
      var publisher = this.publisher;
      this.addNamedListener('PUBLISH_API_CALL', 'apiCall', function PUBLISH_API_CALL(event) {
        process.nextTick(function() {publisher.eventHandler(event);});
      });
      this.addNamedListener('PUBLISH_API_ATTEMPT', 'apiCallAttempt', function PUBLISH_API_ATTEMPT(event) {
        process.nextTick(function() {publisher.eventHandler(event);});
      });
    }
  },

  /**
   * @api private
   */
  validateService: function validateService() {
  },

  /**
   * @api private
   */
  loadServiceClass: function loadServiceClass(serviceConfig) {
    var config = serviceConfig;
    if (!AWS.util.isEmpty(this.api)) {
      return null;
    } else if (config.apiConfig) {
      return AWS.Service.defineServiceApi(this.constructor, config.apiConfig);
    } else if (!this.constructor.services) {
      return null;
    } else {
      config = new AWS.Config(AWS.config);
      config.update(serviceConfig, true);
      var version = config.apiVersions[this.constructor.serviceIdentifier];
      version = version || config.apiVersion;
      return this.getLatestServiceClass(version);
    }
  },

  /**
   * @api private
   */
  getLatestServiceClass: function getLatestServiceClass(version) {
    version = this.getLatestServiceVersion(version);
    if (this.constructor.services[version] === null) {
      AWS.Service.defineServiceApi(this.constructor, version);
    }

    return this.constructor.services[version];
  },

  /**
   * @api private
   */
  getLatestServiceVersion: function getLatestServiceVersion(version) {
    if (!this.constructor.services || this.constructor.services.length === 0) {
      throw new Error('No services defined on ' +
                      this.constructor.serviceIdentifier);
    }

    if (!version) {
      version = 'latest';
    } else if (AWS.util.isType(version, Date)) {
      version = AWS.util.date.iso8601(version).split('T')[0];
    }

    if (Object.hasOwnProperty(this.constructor.services, version)) {
      return version;
    }

    var keys = Object.keys(this.constructor.services).sort();
    var selectedVersion = null;
    for (var i = keys.length - 1; i >= 0; i--) {
      // versions that end in "*" are not available on disk and can be
      // skipped, so do not choose these as selectedVersions
      if (keys[i][keys[i].length - 1] !== '*') {
        selectedVersion = keys[i];
      }
      if (keys[i].substr(0, 10) <= version) {
        return selectedVersion;
      }
    }

    throw new Error('Could not find ' + this.constructor.serviceIdentifier +
                    ' API to satisfy version constraint `' + version + '\'');
  },

  /**
   * @api private
   */
  api: {},

  /**
   * @api private
   */
  defaultRetryCount: 3,

  /**
   * @api private
   */
  customizeRequests: function customizeRequests(callback) {
    if (!callback) {
      this.customRequestHandler = null;
    } else if (typeof callback === 'function') {
      this.customRequestHandler = callback;
    } else {
      throw new Error('Invalid callback type \'' + typeof callback + '\' provided in customizeRequests');
    }
  },

  /**
   * Calls an operation on a service with the given input parameters.
   *
   * @param operation [String] the name of the operation to call on the service.
   * @param params [map] a map of input options for the operation
   * @callback callback function(err, data)
   *   If a callback is supplied, it is called when a response is returned
   *   from the service.
   *   @param err [Error] the error object returned from the request.
   *     Set to `null` if the request is successful.
   *   @param data [Object] the de-serialized data returned from
   *     the request. Set to `null` if a request error occurs.
   */
  makeRequest: function makeRequest(operation, params, callback) {
    if (typeof params === 'function') {
      callback = params;
      params = null;
    }

    params = params || {};
    if (this.config.params) { // copy only toplevel bound params
      var rules = this.api.operations[operation];
      if (rules) {
        params = AWS.util.copy(params);
        AWS.util.each(this.config.params, function(key, value) {
          if (rules.input.members[key]) {
            if (params[key] === undefined || params[key] === null) {
              params[key] = value;
            }
          }
        });
      }
    }

    var request = new AWS.Request(this, operation, params);
    this.addAllRequestListeners(request);
    this.attachMonitoringEmitter(request);
    if (callback) request.send(callback);
    return request;
  },

  /**
   * Calls an operation on a service with the given input parameters, without
   * any authentication data. This method is useful for "public" API operations.
   *
   * @param operation [String] the name of the operation to call on the service.
   * @param params [map] a map of input options for the operation
   * @callback callback function(err, data)
   *   If a callback is supplied, it is called when a response is returned
   *   from the service.
   *   @param err [Error] the error object returned from the request.
   *     Set to `null` if the request is successful.
   *   @param data [Object] the de-serialized data returned from
   *     the request. Set to `null` if a request error occurs.
   */
  makeUnauthenticatedRequest: function makeUnauthenticatedRequest(operation, params, callback) {
    if (typeof params === 'function') {
      callback = params;
      params = {};
    }

    var request = this.makeRequest(operation, params).toUnauthenticated();
    return callback ? request.send(callback) : request;
  },

  /**
   * Waits for a given state
   *
   * @param state [String] the state on the service to wait for
   * @param params [map] a map of parameters to pass with each request
   * @option params $waiter [map] a map of configuration options for the waiter
   * @option params $waiter.delay [Number] The number of seconds to wait between
   *                                       requests
   * @option params $waiter.maxAttempts [Number] The maximum number of requests
   *                                             to send while waiting
   * @callback callback function(err, data)
   *   If a callback is supplied, it is called when a response is returned
   *   from the service.
   *   @param err [Error] the error object returned from the request.
   *     Set to `null` if the request is successful.
   *   @param data [Object] the de-serialized data returned from
   *     the request. Set to `null` if a request error occurs.
   */
  waitFor: function waitFor(state, params, callback) {
    var waiter = new AWS.ResourceWaiter(this, state);
    return waiter.wait(params, callback);
  },

  /**
   * @api private
   */
  addAllRequestListeners: function addAllRequestListeners(request) {
    var list = [AWS.events, AWS.EventListeners.Core, this.serviceInterface(),
                AWS.EventListeners.CorePost];
    for (var i = 0; i < list.length; i++) {
      if (list[i]) request.addListeners(list[i]);
    }

    // disable parameter validation
    if (!this.config.paramValidation) {
      request.removeListener('validate',
        AWS.EventListeners.Core.VALIDATE_PARAMETERS);
    }

    if (this.config.logger) { // add logging events
      request.addListeners(AWS.EventListeners.Logger);
    }

    this.setupRequestListeners(request);
    // call prototype's customRequestHandler
    if (typeof this.constructor.prototype.customRequestHandler === 'function') {
      this.constructor.prototype.customRequestHandler(request);
    }
    // call instance's customRequestHandler
    if (Object.prototype.hasOwnProperty.call(this, 'customRequestHandler') && typeof this.customRequestHandler === 'function') {
      this.customRequestHandler(request);
    }
  },

  /**
   * Event recording metrics for a whole API call.
   * @returns {object} a subset of api call metrics
   * @api private
   */
  apiCallEvent: function apiCallEvent(request) {
    var api = request.service.api.operations[request.operation];
    var monitoringEvent = {
      Type: 'ApiCall',
      Api: api ? api.name : request.operation,
      Version: 1,
      Service: request.service.api.serviceId || request.service.api.endpointPrefix,
      Region: request.httpRequest.region,
      MaxRetriesExceeded: 0,
      UserAgent: request.httpRequest.getUserAgent(),
    };
    var response = request.response;
    if (response.httpResponse.statusCode) {
      monitoringEvent.FinalHttpStatusCode = response.httpResponse.statusCode;
    }
    if (response.error) {
      var error = response.error;
      var statusCode = response.httpResponse.statusCode;
      if (statusCode > 299) {
        if (error.code) monitoringEvent.FinalAwsException = error.code;
        if (error.message) monitoringEvent.FinalAwsExceptionMessage = error.message;
      } else {
        if (error.code || error.name) monitoringEvent.FinalSdkException = error.code || error.name;
        if (error.message) monitoringEvent.FinalSdkExceptionMessage = error.message;
      }
    }
    return monitoringEvent;
  },

  /**
   * Event recording metrics for an API call attempt.
   * @returns {object} a subset of api call attempt metrics
   * @api private
   */
  apiAttemptEvent: function apiAttemptEvent(request) {
    var api = request.service.api.operations[request.operation];
    var monitoringEvent = {
      Type: 'ApiCallAttempt',
      Api: api ? api.name : request.operation,
      Version: 1,
      Service: request.service.api.serviceId || request.service.api.endpointPrefix,
      Fqdn: request.httpRequest.endpoint.hostname,
      UserAgent: request.httpRequest.getUserAgent(),
    };
    var response = request.response;
    if (response.httpResponse.statusCode) {
      monitoringEvent.HttpStatusCode = response.httpResponse.statusCode;
    }
    if (
      !request._unAuthenticated &&
      request.service.config.credentials &&
      request.service.config.credentials.accessKeyId
    ) {
      monitoringEvent.AccessKey = request.service.config.credentials.accessKeyId;
    }
    if (!response.httpResponse.headers) return monitoringEvent;
    if (request.httpRequest.headers['x-amz-security-token']) {
      monitoringEvent.SessionToken = request.httpRequest.headers['x-amz-security-token'];
    }
    if (response.httpResponse.headers['x-amzn-requestid']) {
      monitoringEvent.XAmznRequestId = response.httpResponse.headers['x-amzn-requestid'];
    }
    if (response.httpResponse.headers['x-amz-request-id']) {
      monitoringEvent.XAmzRequestId = response.httpResponse.headers['x-amz-request-id'];
    }
    if (response.httpResponse.headers['x-amz-id-2']) {
      monitoringEvent.XAmzId2 = response.httpResponse.headers['x-amz-id-2'];
    }
    return monitoringEvent;
  },

  /**
   * Add metrics of failed request.
   * @api private
   */
  attemptFailEvent: function attemptFailEvent(request) {
    var monitoringEvent = this.apiAttemptEvent(request);
    var response = request.response;
    var error = response.error;
    if (response.httpResponse.statusCode > 299 ) {
      if (error.code) monitoringEvent.AwsException = error.code;
      if (error.message) monitoringEvent.AwsExceptionMessage = error.message;
    } else {
      if (error.code || error.name) monitoringEvent.SdkException = error.code || error.name;
      if (error.message) monitoringEvent.SdkExceptionMessage = error.message;
    }
    return monitoringEvent;
  },

  /**
   * Attach listeners to request object to fetch metrics of each request
   * and emit data object through \'ApiCall\' and \'ApiCallAttempt\' events.
   * @api private
   */
  attachMonitoringEmitter: function attachMonitoringEmitter(request) {
    var attemptTimestamp; //timestamp marking the beginning of a request attempt
    var attemptStartRealTime; //Start time of request attempt. Used to calculating attemptLatency
    var attemptLatency; //latency from request sent out to http response reaching SDK
    var callStartRealTime; //Start time of API call. Used to calculating API call latency
    var attemptCount = 0; //request.retryCount is not reliable here
    var region; //region cache region for each attempt since it can be updated in plase (e.g. s3)
    var callTimestamp; //timestamp when the request is created
    var self = this;
    var addToHead = true;

    request.on('validate', function () {
      callStartRealTime = AWS.util.realClock.now();
      callTimestamp = Date.now();
    }, addToHead);
    request.on('sign', function () {
      attemptStartRealTime = AWS.util.realClock.now();
      attemptTimestamp = Date.now();
      region = request.httpRequest.region;
      attemptCount++;
    }, addToHead);
    request.on('validateResponse', function() {
      attemptLatency = Math.round(AWS.util.realClock.now() - attemptStartRealTime);
    });
    request.addNamedListener('API_CALL_ATTEMPT', 'success', function API_CALL_ATTEMPT() {
      var apiAttemptEvent = self.apiAttemptEvent(request);
      apiAttemptEvent.Timestamp = attemptTimestamp;
      apiAttemptEvent.AttemptLatency = attemptLatency >= 0 ? attemptLatency : 0;
      apiAttemptEvent.Region = region;
      self.emit('apiCallAttempt', [apiAttemptEvent]);
    });
    request.addNamedListener('API_CALL_ATTEMPT_RETRY', 'retry', function API_CALL_ATTEMPT_RETRY() {
      var apiAttemptEvent = self.attemptFailEvent(request);
      apiAttemptEvent.Timestamp = attemptTimestamp;
      //attemptLatency may not be available if fail before response
      attemptLatency = attemptLatency ||
        Math.round(AWS.util.realClock.now() - attemptStartRealTime);
      apiAttemptEvent.AttemptLatency = attemptLatency >= 0 ? attemptLatency : 0;
      apiAttemptEvent.Region = region;
      self.emit('apiCallAttempt', [apiAttemptEvent]);
    });
    request.addNamedListener('API_CALL', 'complete', function API_CALL() {
      var apiCallEvent = self.apiCallEvent(request);
      apiCallEvent.AttemptCount = attemptCount;
      if (apiCallEvent.AttemptCount <= 0) return;
      apiCallEvent.Timestamp = callTimestamp;
      var latency = Math.round(AWS.util.realClock.now() - callStartRealTime);
      apiCallEvent.Latency = latency >= 0 ? latency : 0;
      var response = request.response;
      if (
        response.error &&
        response.error.retryable &&
        typeof response.retryCount === 'number' &&
        typeof response.maxRetries === 'number' &&
        (response.retryCount >= response.maxRetries)
      ) {
        apiCallEvent.MaxRetriesExceeded = 1;
      }
      self.emit('apiCall', [apiCallEvent]);
    });
  },

  /**
   * Override this method to setup any custom request listeners for each
   * new request to the service.
   *
   * @method_abstract This is an abstract method.
   */
  setupRequestListeners: function setupRequestListeners(request) {
  },

  /**
   * Gets the signing name for a given request
   * @api private
   */
  getSigningName: function getSigningName() {
    return this.api.signingName || this.api.endpointPrefix;
  },

  /**
   * Gets the signer class for a given request
   * @api private
   */
  getSignerClass: function getSignerClass(request) {
    var version;
    // get operation authtype if present
    var operation = null;
    var authtype = '';
    if (request) {
      var operations = request.service.api.operations || {};
      operation = operations[request.operation] || null;
      authtype = operation ? operation.authtype : '';
    }
    if (this.config.signatureVersion) {
      version = this.config.signatureVersion;
    } else if (authtype === 'v4' || authtype === 'v4-unsigned-body') {
      version = 'v4';
    } else if (authtype === 'bearer') {
      version = 'bearer';
    } else {
      version = this.api.signatureVersion;
    }
    return AWS.Signers.RequestSigner.getVersion(version);
  },

  /**
   * @api private
   */
  serviceInterface: function serviceInterface() {
    switch (this.api.protocol) {
      case 'ec2': return AWS.EventListeners.Query;
      case 'query': return AWS.EventListeners.Query;
      case 'json': return AWS.EventListeners.Json;
      case 'rest-json': return AWS.EventListeners.RestJson;
      case 'rest-xml': return AWS.EventListeners.RestXml;
    }
    if (this.api.protocol) {
      throw new Error('Invalid service `protocol\' ' +
        this.api.protocol + ' in API config');
    }
  },

  /**
   * @api private
   */
  successfulResponse: function successfulResponse(resp) {
    return resp.httpResponse.statusCode < 300;
  },

  /**
   * How many times a failed request should be retried before giving up.
   * the defaultRetryCount can be overriden by service classes.
   *
   * @api private
   */
  numRetries: function numRetries() {
    if (this.config.maxRetries !== undefined) {
      return this.config.maxRetries;
    } else {
      return this.defaultRetryCount;
    }
  },

  /**
   * @api private
   */
  retryDelays: function retryDelays(retryCount, err) {
    return AWS.util.calculateRetryDelay(retryCount, this.config.retryDelayOptions, err);
  },

  /**
   * @api private
   */
  retryableError: function retryableError(error) {
    if (this.timeoutError(error)) return true;
    if (this.networkingError(error)) return true;
    if (this.expiredCredentialsError(error)) return true;
    if (this.throttledError(error)) return true;
    if (error.statusCode >= 500) return true;
    return false;
  },

  /**
   * @api private
   */
  networkingError: function networkingError(error) {
    return error.code === 'NetworkingError';
  },

  /**
   * @api private
   */
  timeoutError: function timeoutError(error) {
    return error.code === 'TimeoutError';
  },

  /**
   * @api private
   */
  expiredCredentialsError: function expiredCredentialsError(error) {
    // TODO : this only handles *one* of the expired credential codes
    return (error.code === 'ExpiredTokenException');
  },

  /**
   * @api private
   */
  clockSkewError: function clockSkewError(error) {
    switch (error.code) {
      case 'RequestTimeTooSkewed':
      case 'RequestExpired':
      case 'InvalidSignatureException':
      case 'SignatureDoesNotMatch':
      case 'AuthFailure':
      case 'RequestInTheFuture':
        return true;
      default: return false;
    }
  },

  /**
   * @api private
   */
  getSkewCorrectedDate: function getSkewCorrectedDate() {
    return new Date(Date.now() + this.config.systemClockOffset);
  },

  /**
   * @api private
   */
  applyClockOffset: function applyClockOffset(newServerTime) {
    if (newServerTime) {
      this.config.systemClockOffset = newServerTime - Date.now();
    }
  },

  /**
   * @api private
   */
  isClockSkewed: function isClockSkewed(newServerTime) {
    if (newServerTime) {
      return Math.abs(this.getSkewCorrectedDate().getTime() - newServerTime) >= 300000;
    }
  },

  /**
   * @api private
   */
  throttledError: function throttledError(error) {
    // this logic varies between services
    if (error.statusCode === 429) return true;
    switch (error.code) {
      case 'ProvisionedThroughputExceededException':
      case 'Throttling':
      case 'ThrottlingException':
      case 'RequestLimitExceeded':
      case 'RequestThrottled':
      case 'RequestThrottledException':
      case 'TooManyRequestsException':
      case 'TransactionInProgressException': //dynamodb
      case 'EC2ThrottledException':
        return true;
      default:
        return false;
    }
  },

  /**
   * @api private
   */
  endpointFromTemplate: function endpointFromTemplate(endpoint) {
    if (typeof endpoint !== 'string') return endpoint;

    var e = endpoint;
    e = e.replace(/\{service\}/g, this.api.endpointPrefix);
    e = e.replace(/\{region\}/g, this.config.region);
    e = e.replace(/\{scheme\}/g, this.config.sslEnabled ? 'https' : 'http');
    return e;
  },

  /**
   * @api private
   */
  setEndpoint: function setEndpoint(endpoint) {
    this.endpoint = new AWS.Endpoint(endpoint, this.config);
  },

  /**
   * @api private
   */
  paginationConfig: function paginationConfig(operation, throwException) {
    var paginator = this.api.operations[operation].paginator;
    if (!paginator) {
      if (throwException) {
        var e = new Error();
        throw AWS.util.error(e, 'No pagination configuration for ' + operation);
      }
      return null;
    }

    return paginator;
  }
});

AWS.util.update(AWS.Service, {

  /**
   * Adds one method for each operation described in the api configuration
   *
   * @api private
   */
  defineMethods: function defineMethods(svc) {
    AWS.util.each(svc.prototype.api.operations, function iterator(method) {
      if (svc.prototype[method]) return;
      var operation = svc.prototype.api.operations[method];
      if (operation.authtype === 'none') {
        svc.prototype[method] = function (params, callback) {
          return this.makeUnauthenticatedRequest(method, params, callback);
        };
      } else {
        svc.prototype[method] = function (params, callback) {
          return this.makeRequest(method, params, callback);
        };
      }
    });
  },

  /**
   * Defines a new Service class using a service identifier and list of versions
   * including an optional set of features (functions) to apply to the class
   * prototype.
   *
   * @param serviceIdentifier [String] the identifier for the service
   * @param versions [Array<String>] a list of versions that work with this
   *   service
   * @param features [Object] an object to attach to the prototype
   * @return [Class<Service>] the service class defined by this function.
   */
  defineService: function defineService(serviceIdentifier, versions, features) {
    AWS.Service._serviceMap[serviceIdentifier] = true;
    if (!Array.isArray(versions)) {
      features = versions;
      versions = [];
    }

    var svc = inherit(AWS.Service, features || {});

    if (typeof serviceIdentifier === 'string') {
      AWS.Service.addVersions(svc, versions);

      var identifier = svc.serviceIdentifier || serviceIdentifier;
      svc.serviceIdentifier = identifier;
    } else { // defineService called with an API
      svc.prototype.api = serviceIdentifier;
      AWS.Service.defineMethods(svc);
    }
    AWS.SequentialExecutor.call(this.prototype);
    //util.clientSideMonitoring is only available in node
    if (!this.prototype.publisher && AWS.util.clientSideMonitoring) {
      var Publisher = AWS.util.clientSideMonitoring.Publisher;
      var configProvider = AWS.util.clientSideMonitoring.configProvider;
      var publisherConfig = configProvider();
      this.prototype.publisher = new Publisher(publisherConfig);
      if (publisherConfig.enabled) {
        //if csm is enabled in environment, SDK should send all metrics
        AWS.Service._clientSideMonitoring = true;
      }
    }
    AWS.SequentialExecutor.call(svc.prototype);
    AWS.Service.addDefaultMonitoringListeners(svc.prototype);
    return svc;
  },

  /**
   * @api private
   */
  addVersions: function addVersions(svc, versions) {
    if (!Array.isArray(versions)) versions = [versions];

    svc.services = svc.services || {};
    for (var i = 0; i < versions.length; i++) {
      if (svc.services[versions[i]] === undefined) {
        svc.services[versions[i]] = null;
      }
    }

    svc.apiVersions = Object.keys(svc.services).sort();
  },

  /**
   * @api private
   */
  defineServiceApi: function defineServiceApi(superclass, version, apiConfig) {
    var svc = inherit(superclass, {
      serviceIdentifier: superclass.serviceIdentifier
    });

    function setApi(api) {
      if (api.isApi) {
        svc.prototype.api = api;
      } else {
        svc.prototype.api = new Api(api, {
          serviceIdentifier: superclass.serviceIdentifier
        });
      }
    }

    if (typeof version === 'string') {
      if (apiConfig) {
        setApi(apiConfig);
      } else {
        try {
          setApi(AWS.apiLoader(superclass.serviceIdentifier, version));
        } catch (err) {
          throw AWS.util.error(err, {
            message: 'Could not find API configuration ' +
              superclass.serviceIdentifier + '-' + version
          });
        }
      }
      if (!Object.prototype.hasOwnProperty.call(superclass.services, version)) {
        superclass.apiVersions = superclass.apiVersions.concat(version).sort();
      }
      superclass.services[version] = svc;
    } else {
      setApi(version);
    }

    AWS.Service.defineMethods(svc);
    return svc;
  },

  /**
   * @api private
   */
  hasService: function(identifier) {
    return Object.prototype.hasOwnProperty.call(AWS.Service._serviceMap, identifier);
  },

  /**
   * @param attachOn attach default monitoring listeners to object
   *
   * Each monitoring event should be emitted from service client to service constructor prototype and then
   * to global service prototype like bubbling up. These default monitoring events listener will transfer
   * the monitoring events to the upper layer.
   * @api private
   */
  addDefaultMonitoringListeners: function addDefaultMonitoringListeners(attachOn) {
    attachOn.addNamedListener('MONITOR_EVENTS_BUBBLE', 'apiCallAttempt', function EVENTS_BUBBLE(event) {
      var baseClass = Object.getPrototypeOf(attachOn);
      if (baseClass._events) baseClass.emit('apiCallAttempt', [event]);
    });
    attachOn.addNamedListener('CALL_EVENTS_BUBBLE', 'apiCall', function CALL_EVENTS_BUBBLE(event) {
      var baseClass = Object.getPrototypeOf(attachOn);
      if (baseClass._events) baseClass.emit('apiCall', [event]);
    });
  },

  /**
   * @api private
   */
  _serviceMap: {}
});

AWS.util.mixin(AWS.Service, AWS.SequentialExecutor);

/**
 * @api private
 */
module.exports = AWS.Service;