/var/www/greso.tech/server/nsm/node_modules/@grpc/grpc-js/src
Edit: /var/www/greso.tech/server/nsm/node_modules/@grpc/grpc-js/src/load-balancer-round-robin.ts (7573B)
/*
* 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.
*
*/
import {
LoadBalancer,
ChannelControlHelper,
LoadBalancingConfig,
registerLoadBalancerType,
} from './load-balancer';
import { ConnectivityState } from './connectivity-state';
import {
QueuePicker,
Picker,
PickArgs,
CompletePickResult,
PickResultType,
UnavailablePicker,
} from './picker';
import {
SubchannelAddress,
subchannelAddressToString,
} from './subchannel-address';
import * as logging from './logging';
import { LogVerbosity } from './constants';
import { ConnectivityStateListener, SubchannelInterface } from './subchannel-interface';
const TRACER_NAME = 'round_robin';
function trace(text: string): void {
logging.trace(LogVerbosity.DEBUG, TRACER_NAME, text);
}
const TYPE_NAME = 'round_robin';
class RoundRobinLoadBalancingConfig implements LoadBalancingConfig {
getLoadBalancerName(): string {
return TYPE_NAME;
}
constructor() {}
toJsonObject(): object {
return {
[TYPE_NAME]: {},
};
}
// eslint-disable-next-line @typescript-eslint/no-explicit-any
static createFromJson(obj: any) {
return new RoundRobinLoadBalancingConfig();
}
}
class RoundRobinPicker implements Picker {
constructor(
private readonly subchannelList: SubchannelInterface[],
private nextIndex = 0
) {}
pick(pickArgs: PickArgs): CompletePickResult {
const pickedSubchannel = this.subchannelList[this.nextIndex];
this.nextIndex = (this.nextIndex + 1) % this.subchannelList.length;
return {
pickResultType: PickResultType.COMPLETE,
subchannel: pickedSubchannel,
status: null,
onCallStarted: null,
onCallEnded: null
};
}
/**
* Check what the next subchannel returned would be. Used by the load
* balancer implementation to preserve this part of the picker state if
* possible when a subchannel connects or disconnects.
*/
peekNextSubchannel(): SubchannelInterface {
return this.subchannelList[this.nextIndex];
}
}
interface ConnectivityStateCounts {
[ConnectivityState.CONNECTING]: number;
[ConnectivityState.IDLE]: number;
[ConnectivityState.READY]: number;
[ConnectivityState.SHUTDOWN]: number;
[ConnectivityState.TRANSIENT_FAILURE]: number;
}
export class RoundRobinLoadBalancer implements LoadBalancer {
private subchannels: SubchannelInterface[] = [];
private currentState: ConnectivityState = ConnectivityState.IDLE;
private subchannelStateListener: ConnectivityStateListener;
private subchannelStateCounts: ConnectivityStateCounts;
private currentReadyPicker: RoundRobinPicker | null = null;
constructor(private readonly channelControlHelper: ChannelControlHelper) {
this.subchannelStateCounts = {
[ConnectivityState.CONNECTING]: 0,
[ConnectivityState.IDLE]: 0,
[ConnectivityState.READY]: 0,
[ConnectivityState.SHUTDOWN]: 0,
[ConnectivityState.TRANSIENT_FAILURE]: 0,
};
this.subchannelStateListener = (
subchannel: SubchannelInterface,
previousState: ConnectivityState,
newState: ConnectivityState
) => {
this.subchannelStateCounts[previousState] -= 1;
this.subchannelStateCounts[newState] += 1;
this.calculateAndUpdateState();
if (
newState === ConnectivityState.TRANSIENT_FAILURE ||
newState === ConnectivityState.IDLE
) {
this.channelControlHelper.requestReresolution();
subchannel.startConnecting();
}
};
}
private calculateAndUpdateState() {
if (this.subchannelStateCounts[ConnectivityState.READY] > 0) {
const readySubchannels = this.subchannels.filter(
(subchannel) =>
subchannel.getConnectivityState() === ConnectivityState.READY
);
let index = 0;
if (this.currentReadyPicker !== null) {
index = readySubchannels.indexOf(
this.currentReadyPicker.peekNextSubchannel()
);
if (index < 0) {
index = 0;
}
}
this.updateState(
ConnectivityState.READY,
new RoundRobinPicker(readySubchannels, index)
);
} else if (this.subchannelStateCounts[ConnectivityState.CONNECTING] > 0) {
this.updateState(ConnectivityState.CONNECTING, new QueuePicker(this));
} else if (
this.subchannelStateCounts[ConnectivityState.TRANSIENT_FAILURE] > 0
) {
this.updateState(
ConnectivityState.TRANSIENT_FAILURE,
new UnavailablePicker()
);
} else {
this.updateState(ConnectivityState.IDLE, new QueuePicker(this));
}
}
private updateState(newState: ConnectivityState, picker: Picker) {
trace(
ConnectivityState[this.currentState] +
' -> ' +
ConnectivityState[newState]
);
if (newState === ConnectivityState.READY) {
this.currentReadyPicker = picker as RoundRobinPicker;
} else {
this.currentReadyPicker = null;
}
this.currentState = newState;
this.channelControlHelper.updateState(newState, picker);
}
private resetSubchannelList() {
for (const subchannel of this.subchannels) {
subchannel.removeConnectivityStateListener(this.subchannelStateListener);
subchannel.unref();
this.channelControlHelper.removeChannelzChild(subchannel.getChannelzRef());
}
this.subchannelStateCounts = {
[ConnectivityState.CONNECTING]: 0,
[ConnectivityState.IDLE]: 0,
[ConnectivityState.READY]: 0,
[ConnectivityState.SHUTDOWN]: 0,
[ConnectivityState.TRANSIENT_FAILURE]: 0,
};
this.subchannels = [];
}
updateAddressList(
addressList: SubchannelAddress[],
lbConfig: LoadBalancingConfig
): void {
this.resetSubchannelList();
trace(
'Connect to address list ' +
addressList.map((address) => subchannelAddressToString(address))
);
this.subchannels = addressList.map((address) =>
this.channelControlHelper.createSubchannel(address, {})
);
for (const subchannel of this.subchannels) {
subchannel.ref();
subchannel.addConnectivityStateListener(this.subchannelStateListener);
this.channelControlHelper.addChannelzChild(subchannel.getChannelzRef());
const subchannelState = subchannel.getConnectivityState();
this.subchannelStateCounts[subchannelState] += 1;
if (
subchannelState === ConnectivityState.IDLE ||
subchannelState === ConnectivityState.TRANSIENT_FAILURE
) {
subchannel.startConnecting();
}
}
this.calculateAndUpdateState();
}
exitIdle(): void {
for (const subchannel of this.subchannels) {
subchannel.startConnecting();
}
}
resetBackoff(): void {
/* The pick first load balancer does not have a connection backoff, so this
* does nothing */
}
destroy(): void {
this.resetSubchannelList();
}
getTypeName(): string {
return TYPE_NAME;
}
}
export function setup() {
registerLoadBalancerType(
TYPE_NAME,
RoundRobinLoadBalancer,
RoundRobinLoadBalancingConfig
);
}