'use strict';
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const EventEmitter = require('events');
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const ServerDescription = require('./server_description').ServerDescription;
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const ServerType = require('./server_description').ServerType;
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const TopologyDescription = require('./topology_description').TopologyDescription;
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const TopologyType = require('./topology_description').TopologyType;
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const monitoring = require('./monitoring');
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const calculateDurationInMs = require('../utils').calculateDurationInMs;
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const MongoTimeoutError = require('../error').MongoTimeoutError;
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const Server = require('./server');
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const relayEvents = require('../utils').relayEvents;
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const ReadPreference = require('../topologies/read_preference');
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const readPreferenceServerSelector = require('./server_selectors').readPreferenceServerSelector;
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const writableServerSelector = require('./server_selectors').writableServerSelector;
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const isRetryableWritesSupported = require('../topologies/shared').isRetryableWritesSupported;
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const CoreCursor = require('../cursor').CoreCursor;
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const deprecate = require('util').deprecate;
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const BSON = require('../connection/utils').retrieveBSON();
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const createCompressionInfo = require('../topologies/shared').createCompressionInfo;
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const isRetryableError = require('../error').isRetryableError;
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const isSDAMUnrecoverableError = require('../error').isSDAMUnrecoverableError;
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const ClientSession = require('../sessions').ClientSession;
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const createClientInfo = require('../topologies/shared').createClientInfo;
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const MongoError = require('../error').MongoError;
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const resolveClusterTime = require('../topologies/shared').resolveClusterTime;
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const SrvPoller = require('./srv_polling').SrvPoller;
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const getMMAPError = require('../topologies/shared').getMMAPError;
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// Global state
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let globalTopologyCounter = 0;
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// Constants
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const TOPOLOGY_DEFAULTS = {
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localThresholdMS: 15,
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serverSelectionTimeoutMS: 30000,
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heartbeatFrequencyMS: 10000,
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minHeartbeatFrequencyMS: 500
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};
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// events that we relay to the `Topology`
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const SERVER_RELAY_EVENTS = [
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'serverHeartbeatStarted',
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'serverHeartbeatSucceeded',
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'serverHeartbeatFailed',
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'commandStarted',
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'commandSucceeded',
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'commandFailed',
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// NOTE: Legacy events
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'monitoring'
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];
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// all events we listen to from `Server` instances
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const LOCAL_SERVER_EVENTS = SERVER_RELAY_EVENTS.concat([
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'error',
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'connect',
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'descriptionReceived',
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'close',
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'ended'
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]);
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/**
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* A container of server instances representing a connection to a MongoDB topology.
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*
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* @fires Topology#serverOpening
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* @fires Topology#serverClosed
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* @fires Topology#serverDescriptionChanged
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* @fires Topology#topologyOpening
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* @fires Topology#topologyClosed
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* @fires Topology#topologyDescriptionChanged
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* @fires Topology#serverHeartbeatStarted
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* @fires Topology#serverHeartbeatSucceeded
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* @fires Topology#serverHeartbeatFailed
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*/
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class Topology extends EventEmitter {
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/**
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* Create a topology
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*
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* @param {Array|String} [seedlist] a string list, or array of Server instances to connect to
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* @param {Object} [options] Optional settings
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* @param {Number} [options.localThresholdMS=15] The size of the latency window for selecting among multiple suitable servers
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* @param {Number} [options.serverSelectionTimeoutMS=30000] How long to block for server selection before throwing an error
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* @param {Number} [options.heartbeatFrequencyMS=10000] The frequency with which topology updates are scheduled
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*/
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constructor(seedlist, options) {
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super();
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if (typeof options === 'undefined' && typeof seedlist !== 'string') {
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options = seedlist;
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seedlist = [];
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// this is for legacy single server constructor support
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if (options.host) {
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seedlist.push({ host: options.host, port: options.port });
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}
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}
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seedlist = seedlist || [];
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if (typeof seedlist === 'string') {
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seedlist = parseStringSeedlist(seedlist);
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}
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options = Object.assign({}, TOPOLOGY_DEFAULTS, options);
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const topologyType = topologyTypeFromSeedlist(seedlist, options);
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const topologyId = globalTopologyCounter++;
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const serverDescriptions = seedlist.reduce((result, seed) => {
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if (seed.domain_socket) seed.host = seed.domain_socket;
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const address = seed.port ? `${seed.host}:${seed.port}` : `${seed.host}:27017`;
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result.set(address, new ServerDescription(address));
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return result;
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}, new Map());
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this.s = {
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// the id of this topology
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id: topologyId,
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// passed in options
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options,
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// initial seedlist of servers to connect to
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seedlist: seedlist,
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// the topology description
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description: new TopologyDescription(
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topologyType,
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serverDescriptions,
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options.replicaSet,
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null,
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null,
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null,
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options
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),
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serverSelectionTimeoutMS: options.serverSelectionTimeoutMS,
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heartbeatFrequencyMS: options.heartbeatFrequencyMS,
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minHeartbeatIntervalMS: options.minHeartbeatIntervalMS,
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// allow users to override the cursor factory
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Cursor: options.cursorFactory || CoreCursor,
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// the bson parser
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bson: options.bson || new BSON(),
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// a map of server instances to normalized addresses
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servers: new Map(),
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// Server Session Pool
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sessionPool: null,
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// Active client sessions
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sessions: new Set(),
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// Promise library
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promiseLibrary: options.promiseLibrary || Promise,
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credentials: options.credentials,
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clusterTime: null,
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// timer management
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monitorTimers: [],
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iterationTimers: []
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};
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// amend options for server instance creation
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this.s.options.compression = { compressors: createCompressionInfo(options) };
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// add client info
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this.s.clientInfo = createClientInfo(options);
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if (options.srvHost) {
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this.s.srvPoller =
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options.srvPoller ||
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new SrvPoller({
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heartbeatFrequencyMS: this.s.heartbeatFrequencyMS,
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srvHost: options.srvHost, // TODO: GET THIS
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logger: options.logger,
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loggerLevel: options.loggerLevel
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});
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this.s.detectTopologyDescriptionChange = ev => {
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const previousType = ev.previousDescription.type;
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const newType = ev.newDescription.type;
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if (previousType !== TopologyType.Sharded && newType === TopologyType.Sharded) {
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this.s.handleSrvPolling = srvPollingHandler(this);
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this.s.srvPoller.on('srvRecordDiscovery', this.s.handleSrvPolling);
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this.s.srvPoller.start();
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}
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};
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this.on('topologyDescriptionChanged', this.s.detectTopologyDescriptionChange);
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}
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}
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/**
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* @return A `TopologyDescription` for this topology
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*/
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get description() {
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return this.s.description;
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}
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get parserType() {
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return BSON.native ? 'c++' : 'js';
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}
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/**
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* All raw connections
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* @method
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* @return {Connection[]}
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*/
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connections() {
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return Array.from(this.s.servers.values()).reduce((result, server) => {
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return result.concat(server.s.pool.allConnections());
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}, []);
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}
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/**
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* Initiate server connect
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*
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* @param {Object} [options] Optional settings
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* @param {Array} [options.auth=null] Array of auth options to apply on connect
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* @param {function} [callback] An optional callback called once on the first connected server
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*/
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connect(options, callback) {
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if (typeof options === 'function') (callback = options), (options = {});
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options = options || {};
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// emit SDAM monitoring events
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this.emit('topologyOpening', new monitoring.TopologyOpeningEvent(this.s.id));
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// emit an event for the topology change
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this.emit(
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'topologyDescriptionChanged',
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new monitoring.TopologyDescriptionChangedEvent(
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this.s.id,
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new TopologyDescription(TopologyType.Unknown), // initial is always Unknown
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this.s.description
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)
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);
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connectServers(this, Array.from(this.s.description.servers.values()));
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this.s.connected = true;
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// otherwise, wait for a server to properly connect based on user provided read preference,
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// or primary.
|
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translateReadPreference(options);
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const readPreference = options.readPreference || ReadPreference.primary;
|
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this.selectServer(readPreferenceServerSelector(readPreference), options, (err, server) => {
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if (err) {
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if (typeof callback === 'function') {
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callback(err, null);
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} else {
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this.emit('error', err);
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}
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return;
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}
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const errorHandler = err => {
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server.removeListener('connect', connectHandler);
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if (typeof callback === 'function') callback(err, null);
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};
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const connectHandler = (_, err) => {
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server.removeListener('error', errorHandler);
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this.emit('open', err, this);
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this.emit('connect', this);
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if (typeof callback === 'function') callback(err, this);
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};
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const STATE_CONNECTING = 1;
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if (server.s.state === STATE_CONNECTING) {
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server.once('error', errorHandler);
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server.once('connect', connectHandler);
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return;
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}
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connectHandler();
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});
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}
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/**
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* Close this topology
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*/
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close(options, callback) {
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if (typeof options === 'function') (callback = options), (options = {});
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options = options || {};
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// clear all existing monitor timers
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this.s.monitorTimers.map(timer => clearTimeout(timer));
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this.s.monitorTimers = [];
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this.s.iterationTimers.map(timer => clearTimeout(timer));
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this.s.iterationTimers = [];
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if (this.s.sessionPool) {
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this.s.sessions.forEach(session => session.endSession());
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this.s.sessionPool.endAllPooledSessions();
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}
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if (this.s.srvPoller) {
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this.s.srvPoller.stop();
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if (this.s.handleSrvPolling) {
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this.s.srvPoller.removeListener('srvRecordDiscovery', this.s.handleSrvPolling);
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delete this.s.handleSrvPolling;
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}
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}
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if (this.s.detectTopologyDescriptionChange) {
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this.removeListener('topologyDescriptionChanged', this.s.detectTopologyDescriptionChange);
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delete this.s.detectTopologyDescriptionChange;
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}
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const servers = this.s.servers;
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if (servers.size === 0) {
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this.s.connected = false;
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if (typeof callback === 'function') {
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callback(null, null);
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}
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return;
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}
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// destroy all child servers
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let destroyed = 0;
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servers.forEach(server =>
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destroyServer(server, this, () => {
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destroyed++;
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if (destroyed === servers.size) {
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// emit an event for close
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this.emit('topologyClosed', new monitoring.TopologyClosedEvent(this.s.id));
|
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this.s.connected = false;
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if (typeof callback === 'function') {
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callback(null, null);
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}
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}
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})
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);
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}
|
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/**
|
* Selects a server according to the selection predicate provided
|
*
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* @param {function} [selector] An optional selector to select servers by, defaults to a random selection within a latency window
|
* @param {object} [options] Optional settings related to server selection
|
* @param {number} [options.serverSelectionTimeoutMS] How long to block for server selection before throwing an error
|
* @param {function} callback The callback used to indicate success or failure
|
* @return {Server} An instance of a `Server` meeting the criteria of the predicate provided
|
*/
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selectServer(selector, options, callback) {
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if (typeof options === 'function') {
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callback = options;
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if (typeof selector !== 'function') {
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options = selector;
|
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let readPreference;
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if (selector instanceof ReadPreference) {
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readPreference = selector;
|
} else {
|
translateReadPreference(options);
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readPreference = options.readPreference || ReadPreference.primary;
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}
|
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selector = readPreferenceServerSelector(readPreference);
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} else {
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options = {};
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}
|
}
|
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options = Object.assign(
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{},
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{ serverSelectionTimeoutMS: this.s.serverSelectionTimeoutMS },
|
options
|
);
|
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const isSharded = this.description.type === TopologyType.Sharded;
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const session = options.session;
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const transaction = session && session.transaction;
|
|
if (isSharded && transaction && transaction.server) {
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callback(null, transaction.server);
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return;
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}
|
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// clear out any existing iteration timers
|
this.s.iterationTimers.map(timer => clearTimeout(timer));
|
this.s.iterationTimers = [];
|
|
selectServers(
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this,
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selector,
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options.serverSelectionTimeoutMS,
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process.hrtime(),
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(err, servers) => {
|
if (err) return callback(err, null);
|
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const selectedServer = randomSelection(servers);
|
if (isSharded && transaction && transaction.isActive) {
|
transaction.pinServer(selectedServer);
|
}
|
|
callback(null, selectedServer);
|
}
|
);
|
}
|
|
// Sessions related methods
|
|
/**
|
* @return Whether the topology should initiate selection to determine session support
|
*/
|
shouldCheckForSessionSupport() {
|
return (
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(this.description.type === TopologyType.Single && !this.description.hasKnownServers) ||
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!this.description.hasDataBearingServers
|
);
|
}
|
|
/**
|
* @return Whether sessions are supported on the current topology
|
*/
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hasSessionSupport() {
|
return this.description.logicalSessionTimeoutMinutes != null;
|
}
|
|
/**
|
* Start a logical session
|
*/
|
startSession(options, clientOptions) {
|
const session = new ClientSession(this, this.s.sessionPool, options, clientOptions);
|
session.once('ended', () => {
|
this.s.sessions.delete(session);
|
});
|
|
this.s.sessions.add(session);
|
return session;
|
}
|
|
/**
|
* Send endSessions command(s) with the given session ids
|
*
|
* @param {Array} sessions The sessions to end
|
* @param {function} [callback]
|
*/
|
endSessions(sessions, callback) {
|
if (!Array.isArray(sessions)) {
|
sessions = [sessions];
|
}
|
|
this.command(
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'admin.$cmd',
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{ endSessions: sessions },
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{ readPreference: ReadPreference.primaryPreferred, noResponse: true },
|
() => {
|
// intentionally ignored, per spec
|
if (typeof callback === 'function') callback();
|
}
|
);
|
}
|
|
/**
|
* Update the internal TopologyDescription with a ServerDescription
|
*
|
* @param {object} serverDescription The server to update in the internal list of server descriptions
|
*/
|
serverUpdateHandler(serverDescription) {
|
if (!this.s.description.hasServer(serverDescription.address)) {
|
return;
|
}
|
|
// these will be used for monitoring events later
|
const previousTopologyDescription = this.s.description;
|
const previousServerDescription = this.s.description.servers.get(serverDescription.address);
|
|
// first update the TopologyDescription
|
this.s.description = this.s.description.update(serverDescription);
|
if (this.s.description.compatibilityError) {
|
this.emit('error', new MongoError(this.s.description.compatibilityError));
|
return;
|
}
|
|
// emit monitoring events for this change
|
this.emit(
|
'serverDescriptionChanged',
|
new monitoring.ServerDescriptionChangedEvent(
|
this.s.id,
|
serverDescription.address,
|
previousServerDescription,
|
this.s.description.servers.get(serverDescription.address)
|
)
|
);
|
|
// update server list from updated descriptions
|
updateServers(this, serverDescription);
|
|
// Driver Sessions Spec: "Whenever a driver receives a cluster time from
|
// a server it MUST compare it to the current highest seen cluster time
|
// for the deployment. If the new cluster time is higher than the
|
// highest seen cluster time it MUST become the new highest seen cluster
|
// time. Two cluster times are compared using only the BsonTimestamp
|
// value of the clusterTime embedded field."
|
const clusterTime = serverDescription.$clusterTime;
|
if (clusterTime) {
|
resolveClusterTime(this, clusterTime);
|
}
|
|
this.emit(
|
'topologyDescriptionChanged',
|
new monitoring.TopologyDescriptionChangedEvent(
|
this.s.id,
|
previousTopologyDescription,
|
this.s.description
|
)
|
);
|
}
|
|
auth(credentials, callback) {
|
if (typeof credentials === 'function') (callback = credentials), (credentials = null);
|
if (typeof callback === 'function') callback(null, true);
|
}
|
|
logout(callback) {
|
if (typeof callback === 'function') callback(null, true);
|
}
|
|
// Basic operation support. Eventually this should be moved into command construction
|
// during the command refactor.
|
|
/**
|
* Insert one or more documents
|
*
|
* @param {String} ns The full qualified namespace for this operation
|
* @param {Array} ops An array of documents to insert
|
* @param {Boolean} [options.ordered=true] Execute in order or out of order
|
* @param {Object} [options.writeConcern] Write concern for the operation
|
* @param {Boolean} [options.serializeFunctions=false] Specify if functions on an object should be serialized
|
* @param {Boolean} [options.ignoreUndefined=false] Specify if the BSON serializer should ignore undefined fields
|
* @param {ClientSession} [options.session] Session to use for the operation
|
* @param {boolean} [options.retryWrites] Enable retryable writes for this operation
|
* @param {opResultCallback} callback A callback function
|
*/
|
insert(ns, ops, options, callback) {
|
executeWriteOperation({ topology: this, op: 'insert', ns, ops }, options, callback);
|
}
|
|
/**
|
* Perform one or more update operations
|
*
|
* @param {string} ns The fully qualified namespace for this operation
|
* @param {array} ops An array of updates
|
* @param {boolean} [options.ordered=true] Execute in order or out of order
|
* @param {object} [options.writeConcern] Write concern for the operation
|
* @param {Boolean} [options.serializeFunctions=false] Specify if functions on an object should be serialized
|
* @param {Boolean} [options.ignoreUndefined=false] Specify if the BSON serializer should ignore undefined fields
|
* @param {ClientSession} [options.session] Session to use for the operation
|
* @param {boolean} [options.retryWrites] Enable retryable writes for this operation
|
* @param {opResultCallback} callback A callback function
|
*/
|
update(ns, ops, options, callback) {
|
executeWriteOperation({ topology: this, op: 'update', ns, ops }, options, callback);
|
}
|
|
/**
|
* Perform one or more remove operations
|
*
|
* @param {string} ns The MongoDB fully qualified namespace (ex: db1.collection1)
|
* @param {array} ops An array of removes
|
* @param {boolean} [options.ordered=true] Execute in order or out of order
|
* @param {object} [options.writeConcern={}] Write concern for the operation
|
* @param {Boolean} [options.serializeFunctions=false] Specify if functions on an object should be serialized.
|
* @param {Boolean} [options.ignoreUndefined=false] Specify if the BSON serializer should ignore undefined fields.
|
* @param {ClientSession} [options.session=null] Session to use for the operation
|
* @param {boolean} [options.retryWrites] Enable retryable writes for this operation
|
* @param {opResultCallback} callback A callback function
|
*/
|
remove(ns, ops, options, callback) {
|
executeWriteOperation({ topology: this, op: 'remove', ns, ops }, options, callback);
|
}
|
|
/**
|
* Execute a command
|
*
|
* @method
|
* @param {string} ns The MongoDB fully qualified namespace (ex: db1.collection1)
|
* @param {object} cmd The command hash
|
* @param {ReadPreference} [options.readPreference] Specify read preference if command supports it
|
* @param {Connection} [options.connection] Specify connection object to execute command against
|
* @param {Boolean} [options.serializeFunctions=false] Specify if functions on an object should be serialized.
|
* @param {Boolean} [options.ignoreUndefined=false] Specify if the BSON serializer should ignore undefined fields.
|
* @param {ClientSession} [options.session=null] Session to use for the operation
|
* @param {opResultCallback} callback A callback function
|
*/
|
command(ns, cmd, options, callback) {
|
if (typeof options === 'function') {
|
(callback = options), (options = {}), (options = options || {});
|
}
|
|
translateReadPreference(options);
|
const readPreference = options.readPreference || ReadPreference.primary;
|
|
this.selectServer(readPreferenceServerSelector(readPreference), options, (err, server) => {
|
if (err) {
|
callback(err, null);
|
return;
|
}
|
|
const willRetryWrite =
|
!options.retrying &&
|
!!options.retryWrites &&
|
options.session &&
|
isRetryableWritesSupported(this) &&
|
!options.session.inTransaction() &&
|
isWriteCommand(cmd);
|
|
const cb = (err, result) => {
|
if (!err) return callback(null, result);
|
if (!isRetryableError(err)) {
|
return callback(err);
|
}
|
|
if (willRetryWrite) {
|
const newOptions = Object.assign({}, options, { retrying: true });
|
return this.command(ns, cmd, newOptions, callback);
|
}
|
|
return callback(err);
|
};
|
|
// increment and assign txnNumber
|
if (willRetryWrite) {
|
options.session.incrementTransactionNumber();
|
options.willRetryWrite = willRetryWrite;
|
}
|
|
server.command(ns, cmd, options, cb);
|
});
|
}
|
|
/**
|
* Create a new cursor
|
*
|
* @method
|
* @param {string} ns The MongoDB fully qualified namespace (ex: db1.collection1)
|
* @param {object|Long} cmd Can be either a command returning a cursor or a cursorId
|
* @param {object} [options] Options for the cursor
|
* @param {object} [options.batchSize=0] Batchsize for the operation
|
* @param {array} [options.documents=[]] Initial documents list for cursor
|
* @param {ReadPreference} [options.readPreference] Specify read preference if command supports it
|
* @param {Boolean} [options.serializeFunctions=false] Specify if functions on an object should be serialized.
|
* @param {Boolean} [options.ignoreUndefined=false] Specify if the BSON serializer should ignore undefined fields.
|
* @param {ClientSession} [options.session=null] Session to use for the operation
|
* @param {object} [options.topology] The internal topology of the created cursor
|
* @returns {Cursor}
|
*/
|
cursor(ns, cmd, options) {
|
options = options || {};
|
const topology = options.topology || this;
|
const CursorClass = options.cursorFactory || this.s.Cursor;
|
translateReadPreference(options);
|
|
return new CursorClass(topology, ns, cmd, options);
|
}
|
|
get clientInfo() {
|
return this.s.clientInfo;
|
}
|
|
// Legacy methods for compat with old topology types
|
isConnected() {
|
// console.log('not implemented: `isConnected`');
|
return true;
|
}
|
|
isDestroyed() {
|
// console.log('not implemented: `isDestroyed`');
|
return false;
|
}
|
|
unref() {
|
console.log('not implemented: `unref`');
|
}
|
|
// NOTE: There are many places in code where we explicitly check the last isMaster
|
// to do feature support detection. This should be done any other way, but for
|
// now we will just return the first isMaster seen, which should suffice.
|
lastIsMaster() {
|
const serverDescriptions = Array.from(this.description.servers.values());
|
if (serverDescriptions.length === 0) return {};
|
|
const sd = serverDescriptions.filter(sd => sd.type !== ServerType.Unknown)[0];
|
const result = sd || { maxWireVersion: this.description.commonWireVersion };
|
return result;
|
}
|
|
get logicalSessionTimeoutMinutes() {
|
return this.description.logicalSessionTimeoutMinutes;
|
}
|
|
get bson() {
|
return this.s.bson;
|
}
|
}
|
|
Object.defineProperty(Topology.prototype, 'clusterTime', {
|
enumerable: true,
|
get: function() {
|
return this.s.clusterTime;
|
},
|
set: function(clusterTime) {
|
this.s.clusterTime = clusterTime;
|
}
|
});
|
|
// legacy aliases
|
Topology.prototype.destroy = deprecate(
|
Topology.prototype.close,
|
'destroy() is deprecated, please use close() instead'
|
);
|
|
const RETRYABLE_WRITE_OPERATIONS = ['findAndModify', 'insert', 'update', 'delete'];
|
function isWriteCommand(command) {
|
return RETRYABLE_WRITE_OPERATIONS.some(op => command[op]);
|
}
|
|
/**
|
* Destroys a server, and removes all event listeners from the instance
|
*
|
* @param {Server} server
|
*/
|
function destroyServer(server, topology, callback) {
|
LOCAL_SERVER_EVENTS.forEach(event => server.removeAllListeners(event));
|
|
server.destroy(() => {
|
topology.emit(
|
'serverClosed',
|
new monitoring.ServerClosedEvent(topology.s.id, server.description.address)
|
);
|
|
if (typeof callback === 'function') callback(null, null);
|
});
|
}
|
|
/**
|
* Parses a basic seedlist in string form
|
*
|
* @param {string} seedlist The seedlist to parse
|
*/
|
function parseStringSeedlist(seedlist) {
|
return seedlist.split(',').map(seed => ({
|
host: seed.split(':')[0],
|
port: seed.split(':')[1] || 27017
|
}));
|
}
|
|
function topologyTypeFromSeedlist(seedlist, options) {
|
const replicaSet = options.replicaSet || options.setName || options.rs_name;
|
if (seedlist.length === 1 && !replicaSet) return TopologyType.Single;
|
if (replicaSet) return TopologyType.ReplicaSetNoPrimary;
|
return TopologyType.Unknown;
|
}
|
|
function randomSelection(array) {
|
return array[Math.floor(Math.random() * array.length)];
|
}
|
|
/**
|
* Selects servers using the provided selector
|
*
|
* @private
|
* @param {Topology} topology The topology to select servers from
|
* @param {function} selector The actual predicate used for selecting servers
|
* @param {Number} timeout The max time we are willing wait for selection
|
* @param {Number} start A high precision timestamp for the start of the selection process
|
* @param {function} callback The callback used to convey errors or the resultant servers
|
*/
|
function selectServers(topology, selector, timeout, start, callback) {
|
const duration = calculateDurationInMs(start);
|
if (duration >= timeout) {
|
return callback(new MongoTimeoutError(`Server selection timed out after ${timeout} ms`));
|
}
|
|
// ensure we are connected
|
if (!topology.s.connected) {
|
topology.connect();
|
|
// we want to make sure we're still within the requested timeout window
|
const failToConnectTimer = setTimeout(() => {
|
topology.removeListener('connect', connectHandler);
|
callback(new MongoTimeoutError('Server selection timed out waiting to connect'));
|
}, timeout - duration);
|
|
const connectHandler = () => {
|
clearTimeout(failToConnectTimer);
|
selectServers(topology, selector, timeout, process.hrtime(), callback);
|
};
|
|
topology.once('connect', connectHandler);
|
return;
|
}
|
|
// otherwise, attempt server selection
|
const serverDescriptions = Array.from(topology.description.servers.values());
|
let descriptions;
|
|
// support server selection by options with readPreference
|
if (typeof selector === 'object') {
|
const readPreference = selector.readPreference
|
? selector.readPreference
|
: ReadPreference.primary;
|
|
selector = readPreferenceServerSelector(readPreference);
|
}
|
|
try {
|
descriptions = selector
|
? selector(topology.description, serverDescriptions)
|
: serverDescriptions;
|
} catch (e) {
|
return callback(e, null);
|
}
|
|
if (descriptions.length) {
|
const servers = descriptions.map(description => topology.s.servers.get(description.address));
|
return callback(null, servers);
|
}
|
|
const retrySelection = () => {
|
// clear all existing monitor timers
|
topology.s.monitorTimers.map(timer => clearTimeout(timer));
|
topology.s.monitorTimers = [];
|
|
// ensure all server monitors attempt monitoring soon
|
topology.s.servers.forEach(server => {
|
const timer = setTimeout(
|
() => server.monitor({ heartbeatFrequencyMS: topology.description.heartbeatFrequencyMS }),
|
TOPOLOGY_DEFAULTS.minHeartbeatFrequencyMS
|
);
|
|
topology.s.monitorTimers.push(timer);
|
});
|
|
const descriptionChangedHandler = () => {
|
// successful iteration, clear the check timer
|
clearTimeout(iterationTimer);
|
topology.s.iterationTimers.splice(timerIndex, 1);
|
|
if (topology.description.error) {
|
callback(topology.description.error, null);
|
return;
|
}
|
|
// topology description has changed due to monitoring, reattempt server selection
|
selectServers(topology, selector, timeout, start, callback);
|
};
|
|
const iterationTimer = setTimeout(() => {
|
topology.removeListener('topologyDescriptionChanged', descriptionChangedHandler);
|
callback(new MongoTimeoutError(`Server selection timed out after ${timeout} ms`));
|
}, timeout - duration);
|
|
// track this timer in case we need to clean it up outside this loop
|
const timerIndex = topology.s.iterationTimers.push(iterationTimer);
|
|
topology.once('topologyDescriptionChanged', descriptionChangedHandler);
|
};
|
|
retrySelection();
|
}
|
|
function createAndConnectServer(topology, serverDescription) {
|
topology.emit(
|
'serverOpening',
|
new monitoring.ServerOpeningEvent(topology.s.id, serverDescription.address)
|
);
|
|
const server = new Server(serverDescription, topology.s.options, topology);
|
relayEvents(server, topology, SERVER_RELAY_EVENTS);
|
|
server.once('connect', serverConnectEventHandler(server, topology));
|
server.on('descriptionReceived', topology.serverUpdateHandler.bind(topology));
|
server.on('error', serverErrorEventHandler(server, topology));
|
server.on('close', () => topology.emit('close', server));
|
server.connect();
|
return server;
|
}
|
|
/**
|
* Create `Server` instances for all initially known servers, connect them, and assign
|
* them to the passed in `Topology`.
|
*
|
* @param {Topology} topology The topology responsible for the servers
|
* @param {ServerDescription[]} serverDescriptions A list of server descriptions to connect
|
*/
|
function connectServers(topology, serverDescriptions) {
|
topology.s.servers = serverDescriptions.reduce((servers, serverDescription) => {
|
const server = createAndConnectServer(topology, serverDescription);
|
servers.set(serverDescription.address, server);
|
return servers;
|
}, new Map());
|
}
|
|
function updateServers(topology, incomingServerDescription) {
|
// update the internal server's description
|
if (incomingServerDescription && topology.s.servers.has(incomingServerDescription.address)) {
|
const server = topology.s.servers.get(incomingServerDescription.address);
|
server.s.description = incomingServerDescription;
|
}
|
|
// add new servers for all descriptions we currently don't know about locally
|
for (const serverDescription of topology.description.servers.values()) {
|
if (!topology.s.servers.has(serverDescription.address)) {
|
const server = createAndConnectServer(topology, serverDescription);
|
topology.s.servers.set(serverDescription.address, server);
|
}
|
}
|
|
// for all servers no longer known, remove their descriptions and destroy their instances
|
for (const entry of topology.s.servers) {
|
const serverAddress = entry[0];
|
if (topology.description.hasServer(serverAddress)) {
|
continue;
|
}
|
|
const server = topology.s.servers.get(serverAddress);
|
topology.s.servers.delete(serverAddress);
|
|
// prepare server for garbage collection
|
destroyServer(server, topology);
|
}
|
}
|
|
function serverConnectEventHandler(server, topology) {
|
return function(/* isMaster, err */) {
|
server.monitor({
|
initial: true,
|
heartbeatFrequencyMS: topology.description.heartbeatFrequencyMS
|
});
|
};
|
}
|
|
function serverErrorEventHandler(server, topology) {
|
return function(err) {
|
topology.emit(
|
'serverClosed',
|
new monitoring.ServerClosedEvent(topology.s.id, server.description.address)
|
);
|
|
if (isSDAMUnrecoverableError(err, server)) {
|
resetServerState(server, err, { clearPool: true });
|
return;
|
}
|
|
resetServerState(server, err);
|
};
|
}
|
|
function executeWriteOperation(args, options, callback) {
|
if (typeof options === 'function') (callback = options), (options = {});
|
options = options || {};
|
|
// TODO: once we drop Node 4, use destructuring either here or in arguments.
|
const topology = args.topology;
|
const op = args.op;
|
const ns = args.ns;
|
const ops = args.ops;
|
|
const willRetryWrite =
|
!args.retrying &&
|
!!options.retryWrites &&
|
options.session &&
|
isRetryableWritesSupported(topology) &&
|
!options.session.inTransaction();
|
|
topology.selectServer(writableServerSelector(), options, (err, server) => {
|
if (err) {
|
callback(err, null);
|
return;
|
}
|
|
const handler = (err, result) => {
|
if (!err) return callback(null, result);
|
if (!isRetryableError(err)) {
|
err = getMMAPError(err);
|
return callback(err);
|
}
|
|
if (willRetryWrite) {
|
const newArgs = Object.assign({}, args, { retrying: true });
|
return executeWriteOperation(newArgs, options, callback);
|
}
|
|
return callback(err);
|
};
|
|
if (callback.operationId) {
|
handler.operationId = callback.operationId;
|
}
|
|
// increment and assign txnNumber
|
if (willRetryWrite) {
|
options.session.incrementTransactionNumber();
|
options.willRetryWrite = willRetryWrite;
|
}
|
|
// execute the write operation
|
server[op](ns, ops, options, handler);
|
});
|
}
|
|
/**
|
* Resets the internal state of this server to `Unknown` by simulating an empty ismaster
|
*
|
* @private
|
* @param {Server} server
|
* @param {MongoError} error The error that caused the state reset
|
* @param {object} [options] Optional settings
|
* @param {boolean} [options.clearPool=false] Pool should be cleared out on state reset
|
*/
|
function resetServerState(server, error, options) {
|
options = Object.assign({}, { clearPool: false }, options);
|
|
function resetState() {
|
server.emit(
|
'descriptionReceived',
|
new ServerDescription(server.description.address, null, { error })
|
);
|
server.monitor();
|
}
|
|
if (options.clearPool && server.s.pool) {
|
server.s.pool.reset(() => resetState());
|
return;
|
}
|
|
resetState();
|
}
|
|
function translateReadPreference(options) {
|
if (options.readPreference == null) {
|
return;
|
}
|
|
let r = options.readPreference;
|
if (typeof r === 'string') {
|
options.readPreference = new ReadPreference(r);
|
} else if (r && !(r instanceof ReadPreference) && typeof r === 'object') {
|
const mode = r.mode || r.preference;
|
if (mode && typeof mode === 'string') {
|
options.readPreference = new ReadPreference(mode, r.tags, {
|
maxStalenessSeconds: r.maxStalenessSeconds
|
});
|
}
|
} else if (!(r instanceof ReadPreference)) {
|
throw new TypeError('Invalid read preference: ' + r);
|
}
|
|
return options;
|
}
|
|
function srvPollingHandler(topology) {
|
return function handleSrvPolling(ev) {
|
const previousTopologyDescription = topology.s.description;
|
topology.s.description = topology.s.description.updateFromSrvPollingEvent(ev);
|
if (topology.s.description === previousTopologyDescription) {
|
// Nothing changed, so return
|
return;
|
}
|
|
updateServers(topology);
|
|
topology.emit(
|
'topologyDescriptionChanged',
|
new monitoring.TopologyDescriptionChangedEvent(
|
topology.s.id,
|
previousTopologyDescription,
|
topology.s.description
|
)
|
);
|
};
|
}
|
|
/**
|
* A server opening SDAM monitoring event
|
*
|
* @event Topology#serverOpening
|
* @type {ServerOpeningEvent}
|
*/
|
|
/**
|
* A server closed SDAM monitoring event
|
*
|
* @event Topology#serverClosed
|
* @type {ServerClosedEvent}
|
*/
|
|
/**
|
* A server description SDAM change monitoring event
|
*
|
* @event Topology#serverDescriptionChanged
|
* @type {ServerDescriptionChangedEvent}
|
*/
|
|
/**
|
* A topology open SDAM event
|
*
|
* @event Topology#topologyOpening
|
* @type {TopologyOpeningEvent}
|
*/
|
|
/**
|
* A topology closed SDAM event
|
*
|
* @event Topology#topologyClosed
|
* @type {TopologyClosedEvent}
|
*/
|
|
/**
|
* A topology structure SDAM change event
|
*
|
* @event Topology#topologyDescriptionChanged
|
* @type {TopologyDescriptionChangedEvent}
|
*/
|
|
/**
|
* A topology serverHeartbeatStarted SDAM event
|
*
|
* @event Topology#serverHeartbeatStarted
|
* @type {ServerHeartbeatStartedEvent}
|
*/
|
|
/**
|
* A topology serverHeartbeatFailed SDAM event
|
*
|
* @event Topology#serverHeartbeatFailed
|
* @type {ServerHearbeatFailedEvent}
|
*/
|
|
/**
|
* A topology serverHeartbeatSucceeded SDAM change event
|
*
|
* @event Topology#serverHeartbeatSucceeded
|
* @type {ServerHeartbeatSucceededEvent}
|
*/
|
|
/**
|
* An event emitted indicating a command was started, if command monitoring is enabled
|
*
|
* @event Topology#commandStarted
|
* @type {object}
|
*/
|
|
/**
|
* An event emitted indicating a command succeeded, if command monitoring is enabled
|
*
|
* @event Topology#commandSucceeded
|
* @type {object}
|
*/
|
|
/**
|
* An event emitted indicating a command failed, if command monitoring is enabled
|
*
|
* @event Topology#commandFailed
|
* @type {object}
|
*/
|
|
module.exports = Topology;
|
