subchannel-pool.js
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"use strict";
/*
* Copyright 2019 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
Object.defineProperty(exports, "__esModule", { value: true });
const channel_options_1 = require("./channel-options");
const subchannel_1 = require("./subchannel");
// 10 seconds in milliseconds. This value is arbitrary.
/**
* The amount of time in between checks for dropping subchannels that have no
* other references
*/
const REF_CHECK_INTERVAL = 10000;
class SubchannelPool {
/**
* A pool of subchannels use for making connections. Subchannels with the
* exact same parameters will be reused.
* @param global If true, this is the global subchannel pool. Otherwise, it
* is the pool for a single channel.
*/
constructor(global) {
this.global = global;
this.pool = Object.create(null);
if (global) {
setInterval(() => {
/* These objects are created with Object.create(null), so they do not
* have a prototype, which means that for (... in ...) loops over them
* do not need to be filtered */
// tslint:disable-next-line:forin
for (const channelTarget in this.pool) {
// tslint:disable-next-line:forin
for (const subchannelTarget in this.pool[channelTarget]) {
const subchannelObjArray = this.pool[channelTarget][subchannelTarget];
/* For each subchannel in the pool, try to unref it if it has
* exactly one ref (which is the ref from the pool itself). If that
* does happen, remove the subchannel from the pool */
this.pool[channelTarget][subchannelTarget] = subchannelObjArray.filter(value => !value.subchannel.unrefIfOneRef());
}
}
/* Currently we do not delete keys with empty values. If that results
* in significant memory usage we should change it. */
}, REF_CHECK_INTERVAL).unref();
// Unref because this timer should not keep the event loop running
}
}
/**
* Get a subchannel if one already exists with exactly matching parameters.
* Otherwise, create and save a subchannel with those parameters.
* @param channelTarget
* @param subchannelTarget
* @param channelArguments
* @param channelCredentials
*/
getOrCreateSubchannel(channelTarget, subchannelTarget, channelArguments, channelCredentials) {
if (channelTarget in this.pool) {
if (subchannelTarget in this.pool[channelTarget]) {
const subchannelObjArray = this.pool[channelTarget][subchannelTarget];
for (const subchannelObj of subchannelObjArray) {
if (channel_options_1.channelOptionsEqual(channelArguments, subchannelObj.channelArguments) &&
channelCredentials._equals(subchannelObj.channelCredentials)) {
return subchannelObj.subchannel;
}
}
}
}
// If we get here, no matching subchannel was found
const subchannel = new subchannel_1.Subchannel(channelTarget, subchannelTarget, channelArguments, channelCredentials);
if (!(channelTarget in this.pool)) {
this.pool[channelTarget] = Object.create(null);
}
if (!(subchannelTarget in this.pool[channelTarget])) {
this.pool[channelTarget][subchannelTarget] = [];
}
this.pool[channelTarget][subchannelTarget].push({
channelArguments,
channelCredentials,
subchannel,
});
if (this.global) {
subchannel.ref();
}
return subchannel;
}
}
exports.SubchannelPool = SubchannelPool;
const globalSubchannelPool = new SubchannelPool(true);
/**
* Get either the global subchannel pool, or a new subchannel pool.
* @param global
*/
function getSubchannelPool(global) {
if (global) {
return globalSubchannelPool;
}
else {
return new SubchannelPool(false);
}
}
exports.getSubchannelPool = getSubchannelPool;
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