| 1 | import { ChannelOptions } from './channel-options';
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| 2 | import { Subchannel, SubchannelAddress } from './subchannel';
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| 3 | import { ConnectivityState } from './channel';
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| 4 | import { Picker } from './picker';
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| 5 | /**
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| 6 | * A collection of functions associated with a channel that a load balancer
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| 7 | * can call as necessary.
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| 8 | */
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| 9 | export interface ChannelControlHelper {
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| 10 | /**
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| 11 | * Returns a subchannel connected to the specified address.
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| 12 | * @param subchannelAddress The address to connect to
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| 13 | * @param subchannelArgs Extra channel arguments specified by the load balancer
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| 14 | */
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| 15 | createSubchannel(subchannelAddress: SubchannelAddress, subchannelArgs: ChannelOptions): Subchannel;
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| 16 | /**
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| 17 | * Passes a new subchannel picker up to the channel. This is called if either
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| 18 | * the connectivity state changes or if a different picker is needed for any
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| 19 | * other reason.
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| 20 | * @param connectivityState New connectivity state
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| 21 | * @param picker New picker
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| 22 | */
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| 23 | updateState(connectivityState: ConnectivityState, picker: Picker): void;
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| 24 | /**
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| 25 | * Request new data from the resolver.
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| 26 | */
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| 27 | requestReresolution(): void;
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| 28 | }
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| 29 | /**
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| 30 | * Tracks one or more connected subchannels and determines which subchannel
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| 31 | * each request should use.
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| 32 | */
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| 33 | export interface LoadBalancer {
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| 34 | /**
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| 35 | * Gives the load balancer a new list of addresses to start connecting to.
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| 36 | * The load balancer will start establishing connections with the new list,
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| 37 | * but will continue using any existing connections until the new connections
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| 38 | * are established
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| 39 | * @param addressList The new list of addresses to connect to
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| 40 | * @param lbConfig The load balancing config object from the service config,
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| 41 | * if one was provided
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| 42 | */
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| 43 | updateAddressList(addressList: SubchannelAddress[], lbConfig: LoadBalancingConfig, attributes: {
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| 44 | [key: string]: unknown;
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| 45 | }): void;
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| 46 | /**
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| 47 | * If the load balancer is currently in the IDLE state, start connecting.
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| 48 | */
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| 49 | exitIdle(): void;
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| 50 | /**
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| 51 | * If the load balancer is currently in the CONNECTING or TRANSIENT_FAILURE
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| 52 | * state, reset the current connection backoff timeout to its base value and
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| 53 | * transition to CONNECTING if in TRANSIENT_FAILURE.
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| 54 | */
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| 55 | resetBackoff(): void;
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| 56 | /**
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| 57 | * The load balancer unrefs all of its subchannels and stops calling methods
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| 58 | * of its channel control helper.
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| 59 | */
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| 60 | destroy(): void;
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| 61 | /**
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| 62 | * Get the type name for this load balancer type. Must be constant across an
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| 63 | * entire load balancer implementation class and must match the name that the
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| 64 | * balancer implementation class was registered with.
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| 65 | */
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| 66 | getTypeName(): string;
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| 67 | }
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| 68 | export interface LoadBalancerConstructor {
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| 69 | new (channelControlHelper: ChannelControlHelper): LoadBalancer;
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| 70 | }
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| 71 | export interface LoadBalancingConfig {
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| 72 | getLoadBalancerName(): string;
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| 73 | toJsonObject(): object;
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| 74 | }
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| 75 | export interface LoadBalancingConfigConstructor {
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| 76 | new (...args: any): LoadBalancingConfig;
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| 77 | createFromJson(obj: any): LoadBalancingConfig;
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| 78 | }
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| 79 | export declare function registerLoadBalancerType(typeName: string, loadBalancerType: LoadBalancerConstructor, loadBalancingConfigType: LoadBalancingConfigConstructor): void;
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| 80 | export declare function createLoadBalancer(config: LoadBalancingConfig, channelControlHelper: ChannelControlHelper): LoadBalancer | null;
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| 81 | export declare function isLoadBalancerNameRegistered(typeName: string): boolean;
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| 82 | export declare function getFirstUsableConfig(configs: LoadBalancingConfig[], defaultPickFirst?: true): LoadBalancingConfig;
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| 83 | export declare function validateLoadBalancingConfig(obj: any): LoadBalancingConfig;
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| 84 | export declare function registerAll(): void;
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