95 lines
3.2 KiB
TypeScript
95 lines
3.2 KiB
TypeScript
import { StatusObject } from './call-interface';
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import { Metadata } from './metadata';
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import { Status } from './constants';
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import { LoadBalancer } from './load-balancer';
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import { SubchannelInterface } from './subchannel-interface';
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export declare enum PickResultType {
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COMPLETE = 0,
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QUEUE = 1,
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TRANSIENT_FAILURE = 2,
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DROP = 3
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}
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export interface PickResult {
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pickResultType: PickResultType;
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/**
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* The subchannel to use as the transport for the call. Only meaningful if
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* `pickResultType` is COMPLETE. If null, indicates that the call should be
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* dropped.
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*/
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subchannel: SubchannelInterface | null;
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/**
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* The status object to end the call with. Populated if and only if
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* `pickResultType` is TRANSIENT_FAILURE.
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*/
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status: StatusObject | null;
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onCallStarted: (() => void) | null;
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onCallEnded: ((statusCode: Status) => void) | null;
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}
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export interface CompletePickResult extends PickResult {
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pickResultType: PickResultType.COMPLETE;
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subchannel: SubchannelInterface | null;
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status: null;
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onCallStarted: (() => void) | null;
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onCallEnded: ((statusCode: Status) => void) | null;
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}
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export interface QueuePickResult extends PickResult {
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pickResultType: PickResultType.QUEUE;
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subchannel: null;
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status: null;
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onCallStarted: null;
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onCallEnded: null;
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}
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export interface TransientFailurePickResult extends PickResult {
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pickResultType: PickResultType.TRANSIENT_FAILURE;
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subchannel: null;
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status: StatusObject;
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onCallStarted: null;
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onCallEnded: null;
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}
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export interface DropCallPickResult extends PickResult {
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pickResultType: PickResultType.DROP;
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subchannel: null;
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status: StatusObject;
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onCallStarted: null;
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onCallEnded: null;
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}
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export interface PickArgs {
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metadata: Metadata;
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extraPickInfo: {
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[key: string]: string;
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};
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}
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/**
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* A proxy object representing the momentary state of a load balancer. Picks
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* subchannels or returns other information based on that state. Should be
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* replaced every time the load balancer changes state.
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*/
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export interface Picker {
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pick(pickArgs: PickArgs): PickResult;
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}
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/**
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* A standard picker representing a load balancer in the TRANSIENT_FAILURE
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* state. Always responds to every pick request with an UNAVAILABLE status.
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*/
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export declare class UnavailablePicker implements Picker {
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private status;
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constructor(status?: Partial<StatusObject>);
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pick(pickArgs: PickArgs): TransientFailurePickResult;
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}
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/**
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* A standard picker representing a load balancer in the IDLE or CONNECTING
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* state. Always responds to every pick request with a QUEUE pick result
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* indicating that the pick should be tried again with the next `Picker`. Also
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* reports back to the load balancer that a connection should be established
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* once any pick is attempted.
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* If the childPicker is provided, delegate to it instead of returning the
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* hardcoded QUEUE pick result, but still calls exitIdle.
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*/
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export declare class QueuePicker {
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private loadBalancer;
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private childPicker?;
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private calledExitIdle;
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constructor(loadBalancer: LoadBalancer, childPicker?: Picker | undefined);
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pick(pickArgs: PickArgs): PickResult;
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}
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