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Merge pull request #2202 from murgatroid99/grpc-js-xds_priority_fixes 

grpc-js-xds: Make various fixes to the priority LB policy
This commit is contained in:
Michael Lumish 2022-08-22 16:06:09 -07:00 committed by GitHub
parent 552b710b93 e1b2cad25e
commit ae53dd1a19
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 56 additions and 64 deletions
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120
packages/grpc-js-xds/src/load-balancer-priority.ts
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@ -115,7 +115,6 @@ interface PriorityChildBalancer {
resetBackoff(): void;
deactivate(): void;
maybeReactivate(): void;
cancelFailoverTimer(): void;
isFailoverTimerPending(): boolean;
getConnectivityState(): ConnectivityState;
getPicker(): Picker;
@ -138,6 +137,7 @@ export class PriorityLoadBalancer implements LoadBalancer {
private childBalancer: ChildLoadBalancerHandler;
private failoverTimer: NodeJS.Timer | null = null;
private deactivationTimer: NodeJS.Timer | null = null;
private seenReadyOrIdleSinceTransientFailure = false;
constructor(private parent: PriorityLoadBalancer, private name: string) {
this.childBalancer = new ChildLoadBalancerHandler(experimental.createChildChannelControlHelper(this.parent.channelControlHelper, {
updateState: (connectivityState: ConnectivityState, picker: Picker) => {
@ -145,12 +145,24 @@ export class PriorityLoadBalancer implements LoadBalancer {
},
}));
this.picker = new QueuePicker(this.childBalancer);
this.startFailoverTimer();
}
private updateState(connectivityState: ConnectivityState, picker: Picker) {
trace('Child ' + this.name + ' ' + ConnectivityState[this.connectivityState] + ' -> ' + ConnectivityState[connectivityState]);
this.connectivityState = connectivityState;
this.picker = picker;
if (connectivityState === ConnectivityState.CONNECTING) {
if (this.seenReadyOrIdleSinceTransientFailure && this.failoverTimer === null) {
this.startFailoverTimer();
}
} else if (connectivityState === ConnectivityState.READY || connectivityState === ConnectivityState.IDLE) {
this.seenReadyOrIdleSinceTransientFailure = true;
this.cancelFailoverTimer();
} else if (connectivityState === ConnectivityState.TRANSIENT_FAILURE) {
this.seenReadyOrIdleSinceTransientFailure = false;
this.cancelFailoverTimer();
}
this.parent.onChildStateChange(this);
}
@ -174,13 +186,9 @@ export class PriorityLoadBalancer implements LoadBalancer {
attributes: { [key: string]: unknown }
): void {
this.childBalancer.updateAddressList(addressList, lbConfig, attributes);
this.startFailoverTimer();
}
exitIdle() {
if (this.connectivityState === ConnectivityState.IDLE) {
this.startFailoverTimer();
}
this.childBalancer.exitIdle();
}
@ -204,7 +212,7 @@ export class PriorityLoadBalancer implements LoadBalancer {
}
}
cancelFailoverTimer() {
private cancelFailoverTimer() {
if (this.failoverTimer !== null) {
clearTimeout(this.failoverTimer);
this.failoverTimer = null;
@ -267,6 +275,8 @@ export class PriorityLoadBalancer implements LoadBalancer {
*/
private currentChildFromBeforeUpdate: PriorityChildBalancer | null = null;
private updatesPaused = false;
constructor(private channelControlHelper: ChannelControlHelper) {}
private updateState(state: ConnectivityState, picker: Picker) {
@ -286,6 +296,9 @@ export class PriorityLoadBalancer implements LoadBalancer {
private onChildStateChange(child: PriorityChildBalancer) {
const childState = child.getConnectivityState();
trace('Child ' + child.getName() + ' transitioning to ' + ConnectivityState[childState]);
if (this.updatesPaused) {
return;
}
if (child === this.currentChildFromBeforeUpdate) {
if (
childState === ConnectivityState.READY ||
@ -294,40 +307,11 @@ export class PriorityLoadBalancer implements LoadBalancer {
this.updateState(childState, child.getPicker());
} else {
this.currentChildFromBeforeUpdate = null;
this.tryNextPriority(true);
this.choosePriority();
}
return;
}
const childPriority = this.priorities.indexOf(child.getName());
if (childPriority < 0) {
// child is not in the priority list, ignore updates
return;
}
if (this.currentPriority !== null && childPriority > this.currentPriority) {
// child is lower priority than the currently selected child, ignore updates
return;
}
if (childState === ConnectivityState.TRANSIENT_FAILURE) {
/* Report connecting if and only if the currently selected child is the
* one entering TRANSIENT_FAILURE */
this.tryNextPriority(childPriority === this.currentPriority);
return;
}
if (this.currentPriority === null || childPriority < this.currentPriority) {
/* In this case, either there is no currently selected child or this
* child is higher priority than the currently selected child, so we want
* to switch to it if it is READY or IDLE. */
if (
childState === ConnectivityState.READY ||
childState === ConnectivityState.IDLE
) {
this.selectPriority(childPriority);
}
return;
}
/* The currently selected child has updated state to something other than
* TRANSIENT_FAILURE, so we pass that update along */
this.updateState(childState, child.getPicker());
this.choosePriority();
}
private deleteChild(child: PriorityChildBalancer) {
@ -335,7 +319,7 @@ export class PriorityLoadBalancer implements LoadBalancer {
this.currentChildFromBeforeUpdate = null;
/* If we get to this point, the currentChildFromBeforeUpdate was still in
* use, so we are still trying to connect to the specified priorities */
this.tryNextPriority(true);
this.choosePriority();
}
}
@ -348,7 +332,6 @@ export class PriorityLoadBalancer implements LoadBalancer {
private selectPriority(priority: number) {
this.currentPriority = priority;
const chosenChild = this.children.get(this.priorities[priority])!;
chosenChild.cancelFailoverTimer();
this.updateState(
chosenChild.getConnectivityState(),
chosenChild.getPicker()
@ -360,20 +343,22 @@ export class PriorityLoadBalancer implements LoadBalancer {
}
}
/**
* Check each child in priority order until we find one to use
* @param reportConnecting Whether we should report a CONNECTING state if we
* stop before picking a specific child. This should be true when we have
* not already selected a child.
*/
private tryNextPriority(reportConnecting: boolean) {
for (const [index, childName] of this.priorities.entries()) {
private choosePriority() {
if (this.priorities.length === 0) {
this.updateState(ConnectivityState.TRANSIENT_FAILURE, new UnavailablePicker({code: Status.UNAVAILABLE, details: 'priority policy has empty priority list', metadata: new Metadata()}));
return;
}
this.currentPriority = null;
for (const [priority, childName] of this.priorities.entries()) {
trace('Trying priority ' + priority + ' child ' + childName);
let child = this.children.get(childName);
/* If the child doesn't already exist, create it and update it. */
if (child === undefined) {
if (reportConnecting) {
if (this.currentChildFromBeforeUpdate === null) {
this.updateState(ConnectivityState.CONNECTING, new QueuePicker(this));
}
this.currentPriority = priority;
child = new this.PriorityChildImpl(this, childName);
this.children.set(childName, child);
const childUpdate = this.latestUpdates.get(childName);
@ -383,6 +368,7 @@ export class PriorityLoadBalancer implements LoadBalancer {
childUpdate.lbConfig,
this.latestAttributes
);
return;
}
}
/* We're going to try to use this child, so reactivate it if it has been
@ -392,28 +378,33 @@ export class PriorityLoadBalancer implements LoadBalancer {
child.getConnectivityState() === ConnectivityState.READY ||
child.getConnectivityState() === ConnectivityState.IDLE
) {
this.selectPriority(index);
this.selectPriority(priority);
return;
}
if (child.isFailoverTimerPending()) {
/* This child is still trying to connect. Wait until its failover timer
* has ended to continue to the next one */
if (reportConnecting) {
this.currentPriority = priority;
if (this.currentChildFromBeforeUpdate === null) {
/* This child is still trying to connect. Wait until its failover timer
* has ended to continue to the next one */
this.updateState(ConnectivityState.CONNECTING, new QueuePicker(this));
return;
}
}
}
/* If we didn't find any priority to try, pick the first one in the state
* CONNECTING */
for (const [priority, childName] of this.priorities.entries()) {
let child = this.children.get(childName)!;
if (child.getConnectivityState() === ConnectivityState.CONNECTING) {
this.updateState(child.getConnectivityState(), child.getPicker());
return;
}
}
this.currentPriority = null;
this.currentChildFromBeforeUpdate = null;
this.updateState(
ConnectivityState.TRANSIENT_FAILURE,
new UnavailablePicker({
code: Status.UNAVAILABLE,
details: 'No ready priority',
metadata: new Metadata(),
})
);
// Did not find any child in CONNECTING, delegate to last child
const child = this.children.get(this.priorities[this.priorities.length - 1])!;
this.updateState(child.getConnectivityState(), child.getPicker());
}
updateAddressList(
@ -464,6 +455,7 @@ export class PriorityLoadBalancer implements LoadBalancer {
this.latestAttributes = attributes;
this.latestUpdates.clear();
this.priorities = lbConfig.getPriorities();
this.updatesPaused = true;
/* Pair up the new child configs with the corresponding address lists, and
* update all existing children with their new configs */
for (const [childName, childConfig] of lbConfig.getChildren()) {
@ -492,8 +484,8 @@ export class PriorityLoadBalancer implements LoadBalancer {
child.deactivate();
}
}
// Only report connecting if there are no existing children
this.tryNextPriority(this.children.size === 0);
this.updatesPaused = false;
this.choosePriority();
}
exitIdle(): void {
if (this.currentPriority !== null) {