mirror of
https://github.com/bvanroll/yahoo-thing.git
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667 lines
22 KiB
JavaScript
667 lines
22 KiB
JavaScript
'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 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 MongoNetworkError = require('../error').MongoNetworkError;
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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 Cursor = require('./cursor');
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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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// 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: 10000,
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heartbeatFrequencyMS: 30000,
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minHeartbeatIntervalMS: 500
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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') {
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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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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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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: Object.assign({}, 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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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 || Cursor,
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// the bson parser
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bson:
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options.bson ||
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new BSON([
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BSON.Binary,
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BSON.Code,
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BSON.DBRef,
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BSON.Decimal128,
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BSON.Double,
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BSON.Int32,
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BSON.Long,
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BSON.Map,
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BSON.MaxKey,
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BSON.MinKey,
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BSON.ObjectId,
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BSON.BSONRegExp,
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BSON.Symbol,
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BSON.Timestamp
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])
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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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}
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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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/**
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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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*/
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connect(/* 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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}
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/**
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* Close this topology
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*/
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close(callback) {
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// destroy all child servers
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this.s.servers.forEach(server => server.destroy());
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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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* Selects a server according to the selection predicate provided
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*
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* @param {function} [selector] An optional selector to select servers by, defaults to a random selection within a latency window
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* @return {Server} An instance of a `Server` meeting the criteria of the predicate provided
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*/
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selectServer(selector, options, callback) {
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if (typeof options === 'function') (callback = options), (options = {});
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options = Object.assign(
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{},
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{ serverSelectionTimeoutMS: this.s.serverSelectionTimeoutMS },
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options
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);
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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) => {
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if (err) return callback(err, null);
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callback(null, randomSelection(servers));
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}
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);
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}
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/**
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* Update the internal TopologyDescription with a ServerDescription
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*
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* @param {object} serverDescription The server to update in the internal list of server descriptions
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*/
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serverUpdateHandler(serverDescription) {
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if (!this.s.description.hasServer(serverDescription.address)) {
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return;
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}
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// these will be used for monitoring events later
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const previousTopologyDescription = this.s.description;
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const previousServerDescription = this.s.description.servers.get(serverDescription.address);
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// first update the TopologyDescription
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this.s.description = this.s.description.update(serverDescription);
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// emit monitoring events for this change
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this.emit(
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'serverDescriptionChanged',
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new monitoring.ServerDescriptionChangedEvent(
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this.s.id,
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serverDescription.address,
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previousServerDescription,
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this.s.description.servers.get(serverDescription.address)
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)
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);
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// update server list from updated descriptions
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updateServers(this, serverDescription);
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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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previousTopologyDescription,
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this.s.description
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)
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);
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}
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/**
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* Authenticate using a specified mechanism
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*
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* @param {String} mechanism The auth mechanism used for authentication
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* @param {String} db The db we are authenticating against
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* @param {Object} options Optional settings for the authenticating mechanism
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* @param {authResultCallback} callback A callback function
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*/
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auth(mechanism, db, options, callback) {
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callback(null, null);
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}
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/**
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* Logout from a database
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*
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* @param {String} db The db we are logging out from
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* @param {authResultCallback} callback A callback function
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*/
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logout(db, callback) {
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callback(null, null);
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}
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// Basic operation support. Eventually this should be moved into command construction
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// during the command refactor.
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/**
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* Insert one or more documents
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*
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* @param {String} ns The full qualified namespace for this operation
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* @param {Array} ops An array of documents to insert
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* @param {Boolean} [options.ordered=true] Execute in order or out of order
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* @param {Object} [options.writeConcern] Write concern for the operation
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* @param {Boolean} [options.serializeFunctions=false] Specify if functions on an object should be serialized
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* @param {Boolean} [options.ignoreUndefined=false] Specify if the BSON serializer should ignore undefined fields
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* @param {ClientSession} [options.session] Session to use for the operation
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* @param {boolean} [options.retryWrites] Enable retryable writes for this operation
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* @param {opResultCallback} callback A callback function
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*/
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insert(ns, ops, options, callback) {
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executeWriteOperation({ topology: this, op: 'insert', ns, ops }, options, callback);
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}
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/**
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* Perform one or more update operations
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*
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* @param {string} ns The fully qualified namespace for this operation
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* @param {array} ops An array of updates
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* @param {boolean} [options.ordered=true] Execute in order or out of order
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* @param {object} [options.writeConcern] Write concern for the operation
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* @param {Boolean} [options.serializeFunctions=false] Specify if functions on an object should be serialized
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* @param {Boolean} [options.ignoreUndefined=false] Specify if the BSON serializer should ignore undefined fields
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* @param {ClientSession} [options.session] Session to use for the operation
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* @param {boolean} [options.retryWrites] Enable retryable writes for this operation
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* @param {opResultCallback} callback A callback function
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*/
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update(ns, ops, options, callback) {
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executeWriteOperation({ topology: this, op: 'update', ns, ops }, options, callback);
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}
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/**
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* Perform one or more remove operations
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*
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* @param {string} ns The MongoDB fully qualified namespace (ex: db1.collection1)
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* @param {array} ops An array of removes
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* @param {boolean} [options.ordered=true] Execute in order or out of order
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* @param {object} [options.writeConcern={}] Write concern for the operation
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* @param {Boolean} [options.serializeFunctions=false] Specify if functions on an object should be serialized.
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* @param {Boolean} [options.ignoreUndefined=false] Specify if the BSON serializer should ignore undefined fields.
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* @param {ClientSession} [options.session=null] Session to use for the operation
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* @param {boolean} [options.retryWrites] Enable retryable writes for this operation
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* @param {opResultCallback} callback A callback function
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*/
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remove(ns, ops, options, callback) {
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executeWriteOperation({ topology: this, op: 'remove', ns, ops }, options, callback);
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}
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/**
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* Execute a command
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*
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* @method
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* @param {string} ns The MongoDB fully qualified namespace (ex: db1.collection1)
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* @param {object} cmd The command hash
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* @param {ReadPreference} [options.readPreference] Specify read preference if command supports it
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* @param {Connection} [options.connection] Specify connection object to execute command against
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* @param {Boolean} [options.serializeFunctions=false] Specify if functions on an object should be serialized.
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* @param {Boolean} [options.ignoreUndefined=false] Specify if the BSON serializer should ignore undefined fields.
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* @param {ClientSession} [options.session=null] Session to use for the operation
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* @param {opResultCallback} callback A callback function
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*/
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command(ns, cmd, options, callback) {
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if (typeof options === 'function') {
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(callback = options), (options = {}), (options = options || {});
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}
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const readPreference = options.readPreference ? options.readPreference : ReadPreference.primary;
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this.selectServer(readPreferenceServerSelector(readPreference), (err, server) => {
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if (err) {
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callback(err, null);
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return;
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}
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server.command(ns, cmd, options, callback);
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});
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}
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/**
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* Create a new cursor
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*
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* @method
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* @param {string} ns The MongoDB fully qualified namespace (ex: db1.collection1)
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* @param {object|Long} cmd Can be either a command returning a cursor or a cursorId
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* @param {object} [options] Options for the cursor
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* @param {object} [options.batchSize=0] Batchsize for the operation
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* @param {array} [options.documents=[]] Initial documents list for cursor
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* @param {ReadPreference} [options.readPreference] Specify read preference if command supports it
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* @param {Boolean} [options.serializeFunctions=false] Specify if functions on an object should be serialized.
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* @param {Boolean} [options.ignoreUndefined=false] Specify if the BSON serializer should ignore undefined fields.
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* @param {ClientSession} [options.session=null] Session to use for the operation
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* @param {object} [options.topology] The internal topology of the created cursor
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* @returns {Cursor}
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*/
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cursor(ns, cmd, options) {
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options = options || {};
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const topology = options.topology || this;
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const CursorClass = options.cursorFactory || this.s.Cursor;
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return new CursorClass(this.s.bson, ns, cmd, options, topology, this.s.options);
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}
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}
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// legacy aliases
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Topology.prototype.destroy = deprecate(
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Topology.prototype.close,
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'destroy() is deprecated, please use close() instead'
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);
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function topologyTypeFromSeedlist(seedlist, options) {
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if (seedlist.length === 1 && !options.replicaSet) return TopologyType.Single;
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if (options.replicaSet) return TopologyType.ReplicaSetNoPrimary;
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return TopologyType.Unknown;
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}
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function randomSelection(array) {
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return array[Math.floor(Math.random() * array.length)];
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}
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/**
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* Selects servers using the provided selector
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*
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* @private
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* @param {Topology} topology The topology to select servers from
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* @param {function} selector The actual predicate used for selecting servers
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* @param {Number} timeout The max time we are willing wait for selection
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* @param {Number} start A high precision timestamp for the start of the selection process
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* @param {function} callback The callback used to convey errors or the resultant servers
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*/
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function selectServers(topology, selector, timeout, start, callback) {
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const serverDescriptions = Array.from(topology.description.servers.values());
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let descriptions;
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try {
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descriptions = selector
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? selector(topology.description, serverDescriptions)
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: serverDescriptions;
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} catch (e) {
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return callback(e, null);
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}
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if (descriptions.length) {
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const servers = descriptions.map(description => topology.s.servers.get(description.address));
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return callback(null, servers);
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}
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const duration = calculateDurationInMs(start);
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if (duration >= timeout) {
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return callback(new MongoTimeoutError(`Server selection timed out after ${timeout} ms`));
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}
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const retrySelection = () => {
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// ensure all server monitors attempt monitoring immediately
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topology.s.servers.forEach(server => server.monitor());
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const iterationTimer = setTimeout(() => {
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callback(new MongoTimeoutError('Server selection timed out due to monitoring'));
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}, topology.s.minHeartbeatIntervalMS);
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topology.once('topologyDescriptionChanged', () => {
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// successful iteration, clear the check timer
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clearTimeout(iterationTimer);
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// topology description has changed due to monitoring, reattempt server selection
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selectServers(topology, selector, timeout, start, callback);
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});
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};
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// ensure we are connected
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if (!topology.s.connected) {
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topology.connect();
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// we want to make sure we're still within the requested timeout window
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const failToConnectTimer = setTimeout(() => {
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callback(new MongoTimeoutError('Server selection timed out waiting to connect'));
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}, timeout - duration);
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topology.once('connect', () => {
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clearTimeout(failToConnectTimer);
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retrySelection();
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});
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return;
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}
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retrySelection();
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}
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/**
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* Create `Server` instances for all initially known servers, connect them, and assign
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* them to the passed in `Topology`.
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*
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* @param {Topology} topology The topology responsible for the servers
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* @param {ServerDescription[]} serverDescriptions A list of server descriptions to connect
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*/
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function connectServers(topology, serverDescriptions) {
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topology.s.servers = serverDescriptions.reduce((servers, serverDescription) => {
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// publish an open event for each ServerDescription created
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topology.emit(
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'serverOpening',
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new monitoring.ServerOpeningEvent(topology.s.id, serverDescription.address)
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);
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const server = new Server(serverDescription, topology.s.options);
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relayEvents(server, topology, [
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'serverHeartbeatStarted',
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'serverHeartbeatSucceeded',
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'serverHeartbeatFailed'
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]);
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server.on('descriptionReceived', topology.serverUpdateHandler.bind(topology));
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server.on('connect', serverConnectEventHandler(server, topology));
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servers.set(serverDescription.address, server);
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server.connect();
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return servers;
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}, new Map());
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}
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function updateServers(topology, currentServerDescription) {
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// update the internal server's description
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if (topology.s.servers.has(currentServerDescription.address)) {
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const server = topology.s.servers.get(currentServerDescription.address);
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server.s.description = currentServerDescription;
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}
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// add new servers for all descriptions we currently don't know about locally
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for (const serverDescription of topology.description.servers.values()) {
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if (!topology.s.servers.has(serverDescription.address)) {
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topology.emit(
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'serverOpening',
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new monitoring.ServerOpeningEvent(topology.s.id, serverDescription.address)
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);
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const server = new Server(serverDescription, topology.s.options);
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relayEvents(server, topology, [
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'serverHeartbeatStarted',
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'serverHeartbeatSucceeded',
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'serverHeartbeatFailed'
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]);
|
|
|
|
server.on('descriptionReceived', topology.serverUpdateHandler.bind(topology));
|
|
server.on('connect', serverConnectEventHandler(server, topology));
|
|
topology.s.servers.set(serverDescription.address, server);
|
|
server.connect();
|
|
}
|
|
}
|
|
|
|
// 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);
|
|
|
|
server.destroy(() =>
|
|
topology.emit('serverClosed', new monitoring.ServerClosedEvent(topology.s.id, serverAddress))
|
|
);
|
|
}
|
|
}
|
|
|
|
function serverConnectEventHandler(server, topology) {
|
|
return function(/* ismaster */) {
|
|
topology.emit('connect', topology);
|
|
};
|
|
}
|
|
|
|
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(), (err, server) => {
|
|
if (err) {
|
|
callback(err, null);
|
|
return;
|
|
}
|
|
|
|
const handler = (err, result) => {
|
|
if (!err) return callback(null, result);
|
|
if (!(err instanceof MongoNetworkError) && !err.message.match(/not master/)) {
|
|
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);
|
|
|
|
// we need to increment the statement id if we're in a transaction
|
|
if (options.session && options.session.inTransaction()) {
|
|
options.session.incrementStatementId(ops.length);
|
|
}
|
|
});
|
|
}
|
|
|
|
/**
|
|
* 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}
|
|
*/
|
|
|
|
module.exports = Topology;
|