100 lines
2.9 KiB
JavaScript
100 lines
2.9 KiB
JavaScript
var EventEmitter = require('events').EventEmitter;
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var defaults = require(__dirname + '/defaults');
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var genericPool = require('generic-pool');
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//takes the same config structure as client
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var createPool = function(clientConfig) {
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clientConfig = clientConfig || {};
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var name = JSON.stringify(clientConfig);
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var pool = createPool.all[name];
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if(pool) {
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return pool;
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}
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pool = genericPool.Pool({
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name: name,
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max: defaults.poolSize,
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idleTimeoutMillis: defaults.poolIdleTimeout,
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reapIntervalMillis: defaults.reapIntervalMillis,
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log: defaults.poolLog,
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create: function(cb) {
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var client = new createPool.Client(clientConfig);
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client.connect(function(err) {
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if(err) return cb(err, null);
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//handle connected client background errors by emitting event
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//via the pg object and then removing errored client from the pool
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client.on('error', function(e) {
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pool.emit('error', e, client);
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pool.destroy(client);
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});
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return cb(null, client);
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});
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},
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destroy: function(client) {
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client.end();
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}
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});
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createPool.all[name] = pool;
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//mixin EventEmitter to pool
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EventEmitter.call(pool);
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for(var key in EventEmitter.prototype) {
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if(EventEmitter.prototype.hasOwnProperty(key)) {
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pool[key] = EventEmitter.prototype[key];
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}
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}
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//monkey-patch with connect method
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pool.connect = function(cb) {
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pool.acquire(function(err, client) {
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if(err) return cb(err, null, function() {/*NOOP*/});
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//support both 2 (old) and 3 arguments
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(cb.length > 2 ? newConnect : oldConnect)(pool, client, cb);
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});
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};
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return pool;
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};
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//the old connect method of the pool
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//would automatically subscribe to the 'drain'
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//event and automatically return the client to
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//the pool once 'drain' fired once. This caused
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//a bunch of problems, but for backwards compatibility
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//we're leaving it in
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var alarmDuration = 5000;
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var errorMessage = ['A client has been checked out from the pool for longer than ' + alarmDuration + ' ms.',
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'You might have a leak!',
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'You should use the following new way to check out clients','pg.connect(function(err, client, done)) {',
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' //do something',
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' done(); //call done() to signal you are finished with the client',
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'}'].join(require('os').EOL);
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var oldConnect = function(pool, client, cb) {
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var tid = setTimeout(function() {
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console.error(errorMessage);
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}, alarmDuration);
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var release = function() {
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clearTimeout(tid);
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pool.release(client);
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};
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client.once('drain', release);
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cb(null, client);
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};
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var newConnect = function(pool, client, cb) {
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cb(null, client, function(err) {
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if(err) {
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pool.destroy(client);
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} else {
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pool.release(client);
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}
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});
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};
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//list of all created pools
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createPool.all = {};
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//reference to client constructor
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createPool.Client = require(__dirname + '/client');
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module.exports = createPool;
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