Express_Crud_Example/node_modules/mongodb/lib/cmap/connection_pool.js
2022-01-28 22:33:42 +01:00

484 lines
19 KiB
JavaScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.ConnectionPool = void 0;
const Denque = require("denque");
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 kPermits = Symbol('permits');
/** @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 kCheckedOut = Symbol('checkedOut');
/** @internal */
const kProcessingWaitQueue = Symbol('processingWaitQueue');
/**
* 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;
super();
this.closed = false;
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,
maxIdleTimeMS: (_c = options.maxIdleTimeMS) !== null && _c !== void 0 ? _c : 0,
waitQueueTimeoutMS: (_d = options.waitQueueTimeoutMS) !== null && _d !== void 0 ? _d : 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[kLogger] = new logger_1.Logger('ConnectionPool');
this[kConnections] = new Denque();
this[kPermits] = this.options.maxPoolSize;
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[kCheckedOut] = 0;
this[kProcessingWaitQueue] = false;
process.nextTick(() => {
this.emit(ConnectionPool.CONNECTION_POOL_CREATED, new connection_pool_events_1.ConnectionPoolCreatedEvent(this));
ensureMinPoolSize(this);
});
}
/** The address of the endpoint the pool is connected to */
get address() {
return this.options.hostAddress.toString();
}
/** An integer representing the SDAM generation of the pool */
get generation() {
return this[kGeneration];
}
/** An integer expressing how many total connections (active + in use) the pool currently has */
get totalConnectionCount() {
return this[kConnections].length + (this.options.maxPoolSize - this[kPermits]);
}
/** An integer expressing how many connections are currently available in the pool. */
get availableConnectionCount() {
return this[kConnections].length;
}
get waitQueueSize() {
return this[kWaitQueue].length;
}
get loadBalanced() {
return this.options.loadBalanced;
}
get serviceGenerations() {
return this[kServiceGenerations];
}
get currentCheckedOutCount() {
return this[kCheckedOut];
}
/**
* Get the metrics information for the pool when a wait queue timeout occurs.
*/
waitQueueErrorMetrics() {
return this[kMetrics].info(this.options.maxPoolSize);
}
/**
* 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));
if (this.closed) {
this.emit(ConnectionPool.CONNECTION_CHECK_OUT_FAILED, new connection_pool_events_1.ConnectionCheckOutFailedEvent(this, 'poolClosed'));
callback(new errors_1.PoolClosedError(this));
return;
}
const waitQueueMember = { callback };
const waitQueueTimeoutMS = this.options.waitQueueTimeoutMS;
if (waitQueueTimeoutMS) {
waitQueueMember.timer = 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[kCheckedOut] = this[kCheckedOut] + 1;
this[kWaitQueue].push(waitQueueMember);
process.nextTick(processWaitQueue, this);
}
/**
* Check a connection into the pool.
*
* @param connection - The connection to check in
*/
checkIn(connection) {
const poolClosed = this.closed;
const stale = connectionIsStale(this, connection);
const willDestroy = !!(poolClosed || stale || connection.closed);
if (!willDestroy) {
connection.markAvailable();
this[kConnections].unshift(connection);
}
this[kCheckedOut] = this[kCheckedOut] - 1;
this.emit(ConnectionPool.CONNECTION_CHECKED_IN, new connection_pool_events_1.ConnectionCheckedInEvent(this, connection));
if (willDestroy) {
const reason = connection.closed ? 'error' : poolClosed ? 'poolClosed' : 'stale';
destroyConnection(this, connection, reason);
}
process.nextTick(processWaitQueue, this);
}
/**
* 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.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) {
// TODO(NODE-3483)
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);
}
}
else {
this[kGeneration] += 1;
}
this.emit('connectionPoolCleared', new connection_pool_events_1.ConnectionPoolClearedEvent(this, serviceId));
}
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');
// drain the wait queue
while (this.waitQueueSize) {
const waitQueueMember = this[kWaitQueue].pop();
if (waitQueueMember) {
if (waitQueueMember.timer) {
clearTimeout(waitQueueMember.timer);
}
if (!waitQueueMember[kCancelled]) {
// TODO(NODE-3483): Replace with MongoConnectionPoolClosedError
waitQueueMember.callback(new error_1.MongoRuntimeError('Connection pool closed'));
}
}
}
// clear the min pool size timer
const minPoolSizeTimer = this[kMinPoolSizeTimer];
if (minPoolSizeTimer) {
clearTimeout(minPoolSizeTimer);
}
// end the connection counter
if (typeof this[kConnectionCounter].return === 'function') {
this[kConnectionCounter].return(undefined);
}
// mark the pool as closed immediately
this.closed = true;
(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);
}
});
});
}
}
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 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;
function ensureMinPoolSize(pool) {
if (pool.closed || pool.options.minPoolSize === 0) {
return;
}
const minPoolSize = pool.options.minPoolSize;
for (let i = pool.totalConnectionCount; i < minPoolSize; ++i) {
createConnection(pool);
}
pool[kMinPoolSizeTimer] = setTimeout(() => ensureMinPoolSize(pool), 10);
}
function connectionIsStale(pool, connection) {
const serviceId = connection.serviceId;
if (pool.loadBalanced && serviceId) {
const sid = serviceId.toHexString();
const generation = pool.serviceGenerations.get(sid);
return connection.generation !== generation;
}
return connection.generation !== pool[kGeneration];
}
function connectionIsIdle(pool, connection) {
return !!(pool.options.maxIdleTimeMS && connection.idleTime > pool.options.maxIdleTimeMS);
}
function createConnection(pool, callback) {
const connectOptions = {
...pool.options,
id: pool[kConnectionCounter].next().value,
generation: pool[kGeneration],
cancellationToken: pool[kCancellationToken]
};
pool[kPermits]--;
(0, connect_1.connect)(connectOptions, (err, connection) => {
if (err || !connection) {
pool[kPermits]++;
pool[kLogger].debug(`connection attempt failed with error [${JSON.stringify(err)}]`);
if (typeof callback === 'function') {
callback(err);
}
return;
}
// The pool might have closed since we started trying to create a connection
if (pool.closed) {
connection.destroy({ force: true });
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) => pool.emit(event, e));
}
pool.emit(ConnectionPool.CONNECTION_CREATED, new connection_pool_events_1.ConnectionCreatedEvent(pool, connection));
if (pool.loadBalanced) {
connection.on(connection_1.Connection.PINNED, pinType => pool[kMetrics].markPinned(pinType));
connection.on(connection_1.Connection.UNPINNED, pinType => pool[kMetrics].markUnpinned(pinType));
const serviceId = connection.serviceId;
if (serviceId) {
let generation;
const sid = serviceId.toHexString();
if ((generation = pool.serviceGenerations.get(sid))) {
connection.generation = generation;
}
else {
pool.serviceGenerations.set(sid, 0);
connection.generation = 0;
}
}
}
connection.markAvailable();
pool.emit(ConnectionPool.CONNECTION_READY, new connection_pool_events_1.ConnectionReadyEvent(pool, connection));
// if a callback has been provided, check out the connection immediately
if (typeof callback === 'function') {
callback(undefined, connection);
return;
}
// otherwise add it to the pool for later acquisition, and try to process the wait queue
pool[kConnections].push(connection);
process.nextTick(processWaitQueue, pool);
});
}
function destroyConnection(pool, connection, reason) {
pool.emit(ConnectionPool.CONNECTION_CLOSED, new connection_pool_events_1.ConnectionClosedEvent(pool, connection, reason));
// allow more connections to be created
pool[kPermits]++;
// destroy the connection
process.nextTick(() => connection.destroy());
}
function processWaitQueue(pool) {
if (pool.closed || pool[kProcessingWaitQueue]) {
return;
}
pool[kProcessingWaitQueue] = true;
while (pool.waitQueueSize) {
const waitQueueMember = pool[kWaitQueue].peekFront();
if (!waitQueueMember) {
pool[kWaitQueue].shift();
continue;
}
if (waitQueueMember[kCancelled]) {
pool[kWaitQueue].shift();
continue;
}
if (!pool.availableConnectionCount) {
break;
}
const connection = pool[kConnections].shift();
if (!connection) {
break;
}
const isStale = connectionIsStale(pool, connection);
const isIdle = connectionIsIdle(pool, connection);
if (!isStale && !isIdle && !connection.closed) {
pool.emit(ConnectionPool.CONNECTION_CHECKED_OUT, new connection_pool_events_1.ConnectionCheckedOutEvent(pool, connection));
if (waitQueueMember.timer) {
clearTimeout(waitQueueMember.timer);
}
pool[kWaitQueue].shift();
waitQueueMember.callback(undefined, connection);
}
else {
const reason = connection.closed ? 'error' : isStale ? 'stale' : 'idle';
destroyConnection(pool, connection, reason);
}
}
const maxPoolSize = pool.options.maxPoolSize;
if (pool.waitQueueSize && (maxPoolSize <= 0 || pool.totalConnectionCount < maxPoolSize)) {
createConnection(pool, (err, connection) => {
const waitQueueMember = pool[kWaitQueue].shift();
if (!waitQueueMember || waitQueueMember[kCancelled]) {
if (!err && connection) {
pool[kConnections].push(connection);
}
pool[kProcessingWaitQueue] = false;
return;
}
if (err) {
pool.emit(ConnectionPool.CONNECTION_CHECK_OUT_FAILED, new connection_pool_events_1.ConnectionCheckOutFailedEvent(pool, err));
}
else if (connection) {
pool.emit(ConnectionPool.CONNECTION_CHECKED_OUT, new connection_pool_events_1.ConnectionCheckedOutEvent(pool, connection));
}
if (waitQueueMember.timer) {
clearTimeout(waitQueueMember.timer);
}
waitQueueMember.callback(err, connection);
pool[kProcessingWaitQueue] = false;
process.nextTick(() => processWaitQueue(pool));
});
}
else {
pool[kProcessingWaitQueue] = false;
}
}
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