"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.ConnectionPool = exports.PoolState = void 0;
const Denque = require("denque");
const timers_1 = require("timers");
const constants_1 = require("../constants");
const error_1 = require("../error");
const logger_1 = require("../logger");
const mongo_types_1 = require("../mongo_types");
const utils_1 = require("../utils");
const connect_1 = require("./connect");
const connection_1 = require("./connection");
const connection_pool_events_1 = require("./connection_pool_events");
const errors_1 = require("./errors");
const metrics_1 = require("./metrics");
/** @internal */
const kLogger = Symbol('logger');
/** @internal */
const kConnections = Symbol('connections');
/** @internal */
const kPending = Symbol('pending');
/** @internal */
const kCheckedOut = Symbol('checkedOut');
/** @internal */
const kMinPoolSizeTimer = Symbol('minPoolSizeTimer');
/** @internal */
const kGeneration = Symbol('generation');
/** @internal */
const kServiceGenerations = Symbol('serviceGenerations');
/** @internal */
const kConnectionCounter = Symbol('connectionCounter');
/** @internal */
const kCancellationToken = Symbol('cancellationToken');
/** @internal */
const kWaitQueue = Symbol('waitQueue');
/** @internal */
const kCancelled = Symbol('cancelled');
/** @internal */
const kMetrics = Symbol('metrics');
/** @internal */
const kProcessingWaitQueue = Symbol('processingWaitQueue');
/** @internal */
const kPoolState = Symbol('poolState');
/** @internal */
exports.PoolState = Object.freeze({
paused: 'paused',
ready: 'ready',
closed: 'closed'
});
/**
* A pool of connections which dynamically resizes, and emit events related to pool activity
* @internal
*/
class ConnectionPool extends mongo_types_1.TypedEventEmitter {
/** @internal */
constructor(options) {
var _a, _b, _c, _d, _e;
super();
this.options = Object.freeze({
...options,
connectionType: connection_1.Connection,
maxPoolSize: (_a = options.maxPoolSize) !== null && _a !== void 0 ? _a : 100,
minPoolSize: (_b = options.minPoolSize) !== null && _b !== void 0 ? _b : 0,
maxConnecting: (_c = options.maxConnecting) !== null && _c !== void 0 ? _c : 2,
maxIdleTimeMS: (_d = options.maxIdleTimeMS) !== null && _d !== void 0 ? _d : 0,
waitQueueTimeoutMS: (_e = options.waitQueueTimeoutMS) !== null && _e !== void 0 ? _e : 0,
autoEncrypter: options.autoEncrypter,
metadata: options.metadata
});
if (this.options.minPoolSize > this.options.maxPoolSize) {
throw new error_1.MongoInvalidArgumentError('Connection pool minimum size must not be greater than maximum pool size');
}
this[kPoolState] = exports.PoolState.paused;
this[kLogger] = new logger_1.Logger('ConnectionPool');
this[kConnections] = new Denque();
this[kPending] = 0;
this[kCheckedOut] = 0;
this[kMinPoolSizeTimer] = undefined;
this[kGeneration] = 0;
this[kServiceGenerations] = new Map();
this[kConnectionCounter] = (0, utils_1.makeCounter)(1);
this[kCancellationToken] = new mongo_types_1.CancellationToken();
this[kCancellationToken].setMaxListeners(Infinity);
this[kWaitQueue] = new Denque();
this[kMetrics] = new metrics_1.ConnectionPoolMetrics();
this[kProcessingWaitQueue] = false;
process.nextTick(() => {
this.emit(ConnectionPool.CONNECTION_POOL_CREATED, new connection_pool_events_1.ConnectionPoolCreatedEvent(this));
});
}
/** The address of the endpoint the pool is connected to */
get address() {
return this.options.hostAddress.toString();
}
/**
* Check if the pool has been closed
*
* TODO(NODE-3263): We can remove this property once shell no longer needs it
*/
get closed() {
return this[kPoolState] === exports.PoolState.closed;
}
/** An integer representing the SDAM generation of the pool */
get generation() {
return this[kGeneration];
}
/** An integer expressing how many total connections (available + pending + in use) the pool currently has */
get totalConnectionCount() {
return (this.availableConnectionCount + this.pendingConnectionCount + this.currentCheckedOutCount);
}
/** An integer expressing how many connections are currently available in the pool. */
get availableConnectionCount() {
return this[kConnections].length;
}
get pendingConnectionCount() {
return this[kPending];
}
get currentCheckedOutCount() {
return this[kCheckedOut];
}
get waitQueueSize() {
return this[kWaitQueue].length;
}
get loadBalanced() {
return this.options.loadBalanced;
}
get serviceGenerations() {
return this[kServiceGenerations];
}
/**
* Get the metrics information for the pool when a wait queue timeout occurs.
*/
waitQueueErrorMetrics() {
return this[kMetrics].info(this.options.maxPoolSize);
}
/**
* Set the pool state to "ready"
*/
ready() {
if (this[kPoolState] !== exports.PoolState.paused) {
return;
}
this[kPoolState] = exports.PoolState.ready;
this.emit(ConnectionPool.CONNECTION_POOL_READY, new connection_pool_events_1.ConnectionPoolReadyEvent(this));
(0, timers_1.clearTimeout)(this[kMinPoolSizeTimer]);
this.ensureMinPoolSize();
}
/**
* Check a connection out of this pool. The connection will continue to be tracked, but no reference to it
* will be held by the pool. This means that if a connection is checked out it MUST be checked back in or
* explicitly destroyed by the new owner.
*/
checkOut(callback) {
this.emit(ConnectionPool.CONNECTION_CHECK_OUT_STARTED, new connection_pool_events_1.ConnectionCheckOutStartedEvent(this));
const waitQueueMember = { callback };
const waitQueueTimeoutMS = this.options.waitQueueTimeoutMS;
if (waitQueueTimeoutMS) {
waitQueueMember.timer = (0, timers_1.setTimeout)(() => {
waitQueueMember[kCancelled] = true;
waitQueueMember.timer = undefined;
this.emit(ConnectionPool.CONNECTION_CHECK_OUT_FAILED, new connection_pool_events_1.ConnectionCheckOutFailedEvent(this, 'timeout'));
waitQueueMember.callback(new errors_1.WaitQueueTimeoutError(this.loadBalanced
? this.waitQueueErrorMetrics()
: 'Timed out while checking out a connection from connection pool', this.address));
}, waitQueueTimeoutMS);
}
this[kWaitQueue].push(waitQueueMember);
process.nextTick(() => this.processWaitQueue());
}
/**
* Check a connection into the pool.
*
* @param connection - The connection to check in
*/
checkIn(connection) {
const poolClosed = this.closed;
const stale = this.connectionIsStale(connection);
const willDestroy = !!(poolClosed || stale || connection.closed);
if (!willDestroy) {
connection.markAvailable();
this[kConnections].unshift(connection);
}
this[kCheckedOut]--;
this.emit(ConnectionPool.CONNECTION_CHECKED_IN, new connection_pool_events_1.ConnectionCheckedInEvent(this, connection));
if (willDestroy) {
const reason = connection.closed ? 'error' : poolClosed ? 'poolClosed' : 'stale';
this.destroyConnection(connection, reason);
}
process.nextTick(() => this.processWaitQueue());
}
/**
* Clear the pool
*
* Pool reset is handled by incrementing the pool's generation count. Any existing connection of a
* previous generation will eventually be pruned during subsequent checkouts.
*/
clear(serviceId) {
if (this.closed) {
return;
}
// handle load balanced case
if (this.loadBalanced && serviceId) {
const sid = serviceId.toHexString();
const generation = this.serviceGenerations.get(sid);
// Only need to worry if the generation exists, since it should
// always be there but typescript needs the check.
if (generation == null) {
throw new error_1.MongoRuntimeError('Service generations are required in load balancer mode.');
}
else {
// Increment the generation for the service id.
this.serviceGenerations.set(sid, generation + 1);
}
this.emit(ConnectionPool.CONNECTION_POOL_CLEARED, new connection_pool_events_1.ConnectionPoolClearedEvent(this, serviceId));
return;
}
// handle non load-balanced case
this[kGeneration] += 1;
const alreadyPaused = this[kPoolState] === exports.PoolState.paused;
this[kPoolState] = exports.PoolState.paused;
this.clearMinPoolSizeTimer();
if (!alreadyPaused) {
this.emit(ConnectionPool.CONNECTION_POOL_CLEARED, new connection_pool_events_1.ConnectionPoolClearedEvent(this));
}
this.processWaitQueue();
}
close(_options, _cb) {
let options = _options;
const callback = (_cb !== null && _cb !== void 0 ? _cb : _options);
if (typeof options === 'function') {
options = {};
}
options = Object.assign({ force: false }, options);
if (this.closed) {
return callback();
}
// immediately cancel any in-flight connections
this[kCancellationToken].emit('cancel');
// end the connection counter
if (typeof this[kConnectionCounter].return === 'function') {
this[kConnectionCounter].return(undefined);
}
this[kPoolState] = exports.PoolState.closed;
this.clearMinPoolSizeTimer();
this.processWaitQueue();
(0, utils_1.eachAsync)(this[kConnections].toArray(), (conn, cb) => {
this.emit(ConnectionPool.CONNECTION_CLOSED, new connection_pool_events_1.ConnectionClosedEvent(this, conn, 'poolClosed'));
conn.destroy(options, cb);
}, err => {
this[kConnections].clear();
this.emit(ConnectionPool.CONNECTION_POOL_CLOSED, new connection_pool_events_1.ConnectionPoolClosedEvent(this));
callback(err);
});
}
/**
* Runs a lambda with an implicitly checked out connection, checking that connection back in when the lambda
* has completed by calling back.
*
* NOTE: please note the required signature of `fn`
*
* @remarks When in load balancer mode, connections can be pinned to cursors or transactions.
* In these cases we pass the connection in to this method to ensure it is used and a new
* connection is not checked out.
*
* @param conn - A pinned connection for use in load balancing mode.
* @param fn - A function which operates on a managed connection
* @param callback - The original callback
*/
withConnection(conn, fn, callback) {
if (conn) {
// use the provided connection, and do _not_ check it in after execution
fn(undefined, conn, (fnErr, result) => {
if (typeof callback === 'function') {
if (fnErr) {
callback(fnErr);
}
else {
callback(undefined, result);
}
}
});
return;
}
this.checkOut((err, conn) => {
// don't callback with `err` here, we might want to act upon it inside `fn`
fn(err, conn, (fnErr, result) => {
if (typeof callback === 'function') {
if (fnErr) {
callback(fnErr);
}
else {
callback(undefined, result);
}
}
if (conn) {
this.checkIn(conn);
}
});
});
}
/** Clear the min pool size timer */
clearMinPoolSizeTimer() {
const minPoolSizeTimer = this[kMinPoolSizeTimer];
if (minPoolSizeTimer) {
(0, timers_1.clearTimeout)(minPoolSizeTimer);
}
}
destroyConnection(connection, reason) {
this.emit(ConnectionPool.CONNECTION_CLOSED, new connection_pool_events_1.ConnectionClosedEvent(this, connection, reason));
// destroy the connection
process.nextTick(() => connection.destroy());
}
connectionIsStale(connection) {
const serviceId = connection.serviceId;
if (this.loadBalanced && serviceId) {
const sid = serviceId.toHexString();
const generation = this.serviceGenerations.get(sid);
return connection.generation !== generation;
}
return connection.generation !== this[kGeneration];
}
connectionIsIdle(connection) {
return !!(this.options.maxIdleTimeMS && connection.idleTime > this.options.maxIdleTimeMS);
}
connectionIsPerished(connection) {
const isStale = this.connectionIsStale(connection);
const isIdle = this.connectionIsIdle(connection);
if (!isStale && !isIdle && !connection.closed) {
return false;
}
const reason = connection.closed ? 'error' : isStale ? 'stale' : 'idle';
this.destroyConnection(connection, reason);
return true;
}
createConnection(callback) {
const connectOptions = {
...this.options,
id: this[kConnectionCounter].next().value,
generation: this[kGeneration],
cancellationToken: this[kCancellationToken]
};
this[kPending]++;
// This is our version of a "virtual" no-I/O connection as the spec requires
this.emit(ConnectionPool.CONNECTION_CREATED, new connection_pool_events_1.ConnectionCreatedEvent(this, { id: connectOptions.id }));
(0, connect_1.connect)(connectOptions, (err, connection) => {
if (err || !connection) {
this[kLogger].debug(`connection attempt failed with error [${JSON.stringify(err)}]`);
this[kPending]--;
callback(err !== null && err !== void 0 ? err : new error_1.MongoRuntimeError('Connection creation failed without error'));
return;
}
// The pool might have closed since we started trying to create a connection
if (this[kPoolState] !== exports.PoolState.ready) {
this[kPending]--;
connection.destroy({ force: true });
callback(this.closed ? new errors_1.PoolClosedError(this) : new errors_1.PoolClearedError(this));
return;
}
// forward all events from the connection to the pool
for (const event of [...constants_1.APM_EVENTS, connection_1.Connection.CLUSTER_TIME_RECEIVED]) {
connection.on(event, (e) => this.emit(event, e));
}
if (this.loadBalanced) {
connection.on(connection_1.Connection.PINNED, pinType => this[kMetrics].markPinned(pinType));
connection.on(connection_1.Connection.UNPINNED, pinType => this[kMetrics].markUnpinned(pinType));
const serviceId = connection.serviceId;
if (serviceId) {
let generation;
const sid = serviceId.toHexString();
if ((generation = this.serviceGenerations.get(sid))) {
connection.generation = generation;
}
else {
this.serviceGenerations.set(sid, 0);
connection.generation = 0;
}
}
}
connection.markAvailable();
this.emit(ConnectionPool.CONNECTION_READY, new connection_pool_events_1.ConnectionReadyEvent(this, connection));
this[kPending]--;
callback(undefined, connection);
return;
});
}
ensureMinPoolSize() {
const minPoolSize = this.options.minPoolSize;
if (this[kPoolState] !== exports.PoolState.ready || minPoolSize === 0) {
return;
}
for (let i = 0; i < this[kConnections].length; i++) {
const connection = this[kConnections].peekAt(i);
if (connection && this.connectionIsPerished(connection)) {
this[kConnections].removeOne(i);
}
}
if (this.totalConnectionCount < minPoolSize &&
this.pendingConnectionCount < this.options.maxConnecting) {
// NOTE: ensureMinPoolSize should not try to get all the pending
// connection permits because that potentially delays the availability of
// the connection to a checkout request
this.createConnection((err, connection) => {
if (!err && connection) {
this[kConnections].push(connection);
process.nextTick(() => this.processWaitQueue());
}
if (this[kPoolState] === exports.PoolState.ready) {
(0, timers_1.clearTimeout)(this[kMinPoolSizeTimer]);
this[kMinPoolSizeTimer] = (0, timers_1.setTimeout)(() => this.ensureMinPoolSize(), 10);
}
});
}
else {
(0, timers_1.clearTimeout)(this[kMinPoolSizeTimer]);
this[kMinPoolSizeTimer] = (0, timers_1.setTimeout)(() => this.ensureMinPoolSize(), 100);
}
}
processWaitQueue() {
if (this[kProcessingWaitQueue]) {
return;
}
this[kProcessingWaitQueue] = true;
while (this.waitQueueSize) {
const waitQueueMember = this[kWaitQueue].peekFront();
if (!waitQueueMember) {
this[kWaitQueue].shift();
continue;
}
if (waitQueueMember[kCancelled]) {
this[kWaitQueue].shift();
continue;
}
if (this[kPoolState] !== exports.PoolState.ready) {
const reason = this.closed ? 'poolClosed' : 'connectionError';
const error = this.closed ? new errors_1.PoolClosedError(this) : new errors_1.PoolClearedError(this);
this.emit(ConnectionPool.CONNECTION_CHECK_OUT_FAILED, new connection_pool_events_1.ConnectionCheckOutFailedEvent(this, reason));
if (waitQueueMember.timer) {
(0, timers_1.clearTimeout)(waitQueueMember.timer);
}
this[kWaitQueue].shift();
waitQueueMember.callback(error);
continue;
}
if (!this.availableConnectionCount) {
break;
}
const connection = this[kConnections].shift();
if (!connection) {
break;
}
if (!this.connectionIsPerished(connection)) {
this[kCheckedOut]++;
this.emit(ConnectionPool.CONNECTION_CHECKED_OUT, new connection_pool_events_1.ConnectionCheckedOutEvent(this, connection));
if (waitQueueMember.timer) {
(0, timers_1.clearTimeout)(waitQueueMember.timer);
}
this[kWaitQueue].shift();
waitQueueMember.callback(undefined, connection);
}
}
const { maxPoolSize, maxConnecting } = this.options;
while (this.waitQueueSize > 0 &&
this.pendingConnectionCount < maxConnecting &&
(maxPoolSize === 0 || this.totalConnectionCount < maxPoolSize)) {
const waitQueueMember = this[kWaitQueue].shift();
if (!waitQueueMember || waitQueueMember[kCancelled]) {
continue;
}
this.createConnection((err, connection) => {
if (waitQueueMember[kCancelled]) {
if (!err && connection) {
this[kConnections].push(connection);
}
}
else {
if (err) {
this.emit(ConnectionPool.CONNECTION_CHECK_OUT_FAILED, new connection_pool_events_1.ConnectionCheckOutFailedEvent(this, 'connectionError'));
}
else if (connection) {
this[kCheckedOut]++;
this.emit(ConnectionPool.CONNECTION_CHECKED_OUT, new connection_pool_events_1.ConnectionCheckedOutEvent(this, connection));
}
if (waitQueueMember.timer) {
(0, timers_1.clearTimeout)(waitQueueMember.timer);
}
waitQueueMember.callback(err, connection);
}
process.nextTick(() => this.processWaitQueue());
});
}
this[kProcessingWaitQueue] = false;
}
}
exports.ConnectionPool = ConnectionPool;
/**
* Emitted when the connection pool is created.
* @event
*/
ConnectionPool.CONNECTION_POOL_CREATED = constants_1.CONNECTION_POOL_CREATED;
/**
* Emitted once when the connection pool is closed
* @event
*/
ConnectionPool.CONNECTION_POOL_CLOSED = constants_1.CONNECTION_POOL_CLOSED;
/**
* Emitted each time the connection pool is cleared and it's generation incremented
* @event
*/
ConnectionPool.CONNECTION_POOL_CLEARED = constants_1.CONNECTION_POOL_CLEARED;
/**
* Emitted each time the connection pool is marked ready
* @event
*/
ConnectionPool.CONNECTION_POOL_READY = constants_1.CONNECTION_POOL_READY;
/**
* Emitted when a connection is created.
* @event
*/
ConnectionPool.CONNECTION_CREATED = constants_1.CONNECTION_CREATED;
/**
* Emitted when a connection becomes established, and is ready to use
* @event
*/
ConnectionPool.CONNECTION_READY = constants_1.CONNECTION_READY;
/**
* Emitted when a connection is closed
* @event
*/
ConnectionPool.CONNECTION_CLOSED = constants_1.CONNECTION_CLOSED;
/**
* Emitted when an attempt to check out a connection begins
* @event
*/
ConnectionPool.CONNECTION_CHECK_OUT_STARTED = constants_1.CONNECTION_CHECK_OUT_STARTED;
/**
* Emitted when an attempt to check out a connection fails
* @event
*/
ConnectionPool.CONNECTION_CHECK_OUT_FAILED = constants_1.CONNECTION_CHECK_OUT_FAILED;
/**
* Emitted each time a connection is successfully checked out of the connection pool
* @event
*/
ConnectionPool.CONNECTION_CHECKED_OUT = constants_1.CONNECTION_CHECKED_OUT;
/**
* Emitted each time a connection is successfully checked into the connection pool
* @event
*/
ConnectionPool.CONNECTION_CHECKED_IN = constants_1.CONNECTION_CHECKED_IN;
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