204 lines
8.7 KiB
JavaScript
204 lines
8.7 KiB
JavaScript
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"use strict";
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/*
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* Copyright 2019 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.RoundRobinLoadBalancer = void 0;
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exports.setup = setup;
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const load_balancer_1 = require("./load-balancer");
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const connectivity_state_1 = require("./connectivity-state");
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const picker_1 = require("./picker");
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const logging = require("./logging");
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const constants_1 = require("./constants");
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const subchannel_address_1 = require("./subchannel-address");
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const load_balancer_pick_first_1 = require("./load-balancer-pick-first");
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const TRACER_NAME = 'round_robin';
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function trace(text) {
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logging.trace(constants_1.LogVerbosity.DEBUG, TRACER_NAME, text);
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}
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const TYPE_NAME = 'round_robin';
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class RoundRobinLoadBalancingConfig {
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getLoadBalancerName() {
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return TYPE_NAME;
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}
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constructor() { }
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toJsonObject() {
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return {
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[TYPE_NAME]: {},
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};
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}
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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static createFromJson(obj) {
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return new RoundRobinLoadBalancingConfig();
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}
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}
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class RoundRobinPicker {
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constructor(children, nextIndex = 0) {
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this.children = children;
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this.nextIndex = nextIndex;
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}
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pick(pickArgs) {
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const childPicker = this.children[this.nextIndex].picker;
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this.nextIndex = (this.nextIndex + 1) % this.children.length;
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return childPicker.pick(pickArgs);
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}
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/**
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* Check what the next subchannel returned would be. Used by the load
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* balancer implementation to preserve this part of the picker state if
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* possible when a subchannel connects or disconnects.
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*/
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peekNextEndpoint() {
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return this.children[this.nextIndex].endpoint;
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}
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}
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function rotateArray(list, startIndex) {
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return [...list.slice(startIndex), ...list.slice(0, startIndex)];
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}
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class RoundRobinLoadBalancer {
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constructor(channelControlHelper) {
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this.channelControlHelper = channelControlHelper;
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this.children = [];
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this.currentState = connectivity_state_1.ConnectivityState.IDLE;
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this.currentReadyPicker = null;
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this.updatesPaused = false;
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this.lastError = null;
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this.childChannelControlHelper = (0, load_balancer_1.createChildChannelControlHelper)(channelControlHelper, {
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updateState: (connectivityState, picker, errorMessage) => {
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/* Ensure that name resolution is requested again after active
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* connections are dropped. This is more aggressive than necessary to
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* accomplish that, so we are counting on resolvers to have
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* reasonable rate limits. */
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if (this.currentState === connectivity_state_1.ConnectivityState.READY && connectivityState !== connectivity_state_1.ConnectivityState.READY) {
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this.channelControlHelper.requestReresolution();
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}
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if (errorMessage) {
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this.lastError = errorMessage;
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}
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this.calculateAndUpdateState();
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},
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});
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}
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countChildrenWithState(state) {
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return this.children.filter(child => child.getConnectivityState() === state)
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.length;
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}
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calculateAndUpdateState() {
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if (this.updatesPaused) {
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return;
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}
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if (this.countChildrenWithState(connectivity_state_1.ConnectivityState.READY) > 0) {
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const readyChildren = this.children.filter(child => child.getConnectivityState() === connectivity_state_1.ConnectivityState.READY);
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let index = 0;
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if (this.currentReadyPicker !== null) {
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const nextPickedEndpoint = this.currentReadyPicker.peekNextEndpoint();
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index = readyChildren.findIndex(child => (0, subchannel_address_1.endpointEqual)(child.getEndpoint(), nextPickedEndpoint));
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if (index < 0) {
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index = 0;
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}
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}
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this.updateState(connectivity_state_1.ConnectivityState.READY, new RoundRobinPicker(readyChildren.map(child => ({
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endpoint: child.getEndpoint(),
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picker: child.getPicker(),
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})), index), null);
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}
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else if (this.countChildrenWithState(connectivity_state_1.ConnectivityState.CONNECTING) > 0) {
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this.updateState(connectivity_state_1.ConnectivityState.CONNECTING, new picker_1.QueuePicker(this), null);
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}
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else if (this.countChildrenWithState(connectivity_state_1.ConnectivityState.TRANSIENT_FAILURE) > 0) {
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const errorMessage = `round_robin: No connection established. Last error: ${this.lastError}`;
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this.updateState(connectivity_state_1.ConnectivityState.TRANSIENT_FAILURE, new picker_1.UnavailablePicker({
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details: errorMessage,
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}), errorMessage);
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}
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else {
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this.updateState(connectivity_state_1.ConnectivityState.IDLE, new picker_1.QueuePicker(this), null);
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}
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/* round_robin should keep all children connected, this is how we do that.
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* We can't do this more efficiently in the individual child's updateState
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* callback because that doesn't have a reference to which child the state
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* change is associated with. */
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for (const child of this.children) {
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if (child.getConnectivityState() === connectivity_state_1.ConnectivityState.IDLE) {
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child.exitIdle();
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}
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}
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}
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updateState(newState, picker, errorMessage) {
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trace(connectivity_state_1.ConnectivityState[this.currentState] +
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' -> ' +
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connectivity_state_1.ConnectivityState[newState]);
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if (newState === connectivity_state_1.ConnectivityState.READY) {
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this.currentReadyPicker = picker;
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}
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else {
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this.currentReadyPicker = null;
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}
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this.currentState = newState;
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this.channelControlHelper.updateState(newState, picker, errorMessage);
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}
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resetSubchannelList() {
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for (const child of this.children) {
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child.destroy();
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}
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this.children = [];
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}
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updateAddressList(maybeEndpointList, lbConfig, options, resolutionNote) {
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if (!(lbConfig instanceof RoundRobinLoadBalancingConfig)) {
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return false;
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}
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if (!maybeEndpointList.ok) {
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if (this.children.length === 0) {
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this.updateState(connectivity_state_1.ConnectivityState.TRANSIENT_FAILURE, new picker_1.UnavailablePicker(maybeEndpointList.error), maybeEndpointList.error.details);
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}
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return true;
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}
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const startIndex = (Math.random() * maybeEndpointList.value.length) | 0;
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const endpointList = rotateArray(maybeEndpointList.value, startIndex);
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this.resetSubchannelList();
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if (endpointList.length === 0) {
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const errorMessage = `No addresses resolved. Resolution note: ${resolutionNote}`;
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this.updateState(connectivity_state_1.ConnectivityState.TRANSIENT_FAILURE, new picker_1.UnavailablePicker({ details: errorMessage }), errorMessage);
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}
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trace('Connect to endpoint list ' + endpointList.map(subchannel_address_1.endpointToString));
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this.updatesPaused = true;
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this.children = endpointList.map(endpoint => new load_balancer_pick_first_1.LeafLoadBalancer(endpoint, this.childChannelControlHelper, options, resolutionNote));
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for (const child of this.children) {
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child.startConnecting();
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}
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this.updatesPaused = false;
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this.calculateAndUpdateState();
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return true;
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}
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exitIdle() {
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/* The round_robin LB policy is only in the IDLE state if it has no
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* addresses to try to connect to and it has no picked subchannel.
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* In that case, there is no meaningful action that can be taken here. */
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}
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resetBackoff() {
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// This LB policy has no backoff to reset
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}
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destroy() {
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this.resetSubchannelList();
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}
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getTypeName() {
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return TYPE_NAME;
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}
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}
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exports.RoundRobinLoadBalancer = RoundRobinLoadBalancer;
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function setup() {
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(0, load_balancer_1.registerLoadBalancerType)(TYPE_NAME, RoundRobinLoadBalancer, RoundRobinLoadBalancingConfig);
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}
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//# sourceMappingURL=load-balancer-round-robin.js.map
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