grpc-js-xds: Implement ring_hash LB policy

Author: murgatroid99

packages/grpc-js-xds/gulpfile.ts

@@ -63,6 +63,7 @@ const compile = checkTask(() => execNpmCommand('compile'));
 const runTests = checkTask(() => {
   process.env.GRPC_EXPERIMENTAL_XDS_FEDERATION = 'true';
   process.env.GRPC_EXPERIMENTAL_XDS_CUSTOM_LB_CONFIG = 'true';
+  process.env.GRPC_XDS_EXPERIMENTAL_ENABLE_RING_HASH = 'true';
   return gulp.src(`${outDir}/test/**/*.js`)
     .pipe(mocha({reporter: 'mocha-jenkins-reporter',
                  require: ['ts-node/register']}));

packages/grpc-js-xds/src/environment.ts

@@ -20,3 +20,4 @@ export const EXPERIMENTAL_OUTLIER_DETECTION = (process.env.GRPC_EXPERIMENTAL_ENA
 export const EXPERIMENTAL_RETRY = (process.env.GRPC_XDS_EXPERIMENTAL_ENABLE_RETRY ?? 'true') === 'true';
 export const EXPERIMENTAL_FEDERATION = (process.env.GRPC_EXPERIMENTAL_XDS_FEDERATION ?? 'false') === 'true';
 export const EXPERIMENTAL_CUSTOM_LB_CONFIG = (process.env.GRPC_EXPERIMENTAL_XDS_CUSTOM_LB_CONFIG ?? 'false') === 'true';
+export const EXPERIMENTAL_RING_HASH = (process.env.GRPC_XDS_EXPERIMENTAL_ENABLE_RING_HASH ?? 'false') === 'true';

packages/grpc-js-xds/src/http-filter.ts

@@ -116,7 +116,7 @@ export function validateTopLevelFilter(httpFilter: HttpFilter__Output): boolean
   try {
     typeUrl = getTopLevelFilterUrl(encodedConfig);
   } catch (e) {
-    trace(httpFilter.name + ' validation failed with error ' + e.message);
+    trace(httpFilter.name + ' validation failed with error ' + (e as Error).message);
     return false;
   }
   const registryEntry = FILTER_REGISTRY.get(typeUrl);
@@ -243,4 +243,4 @@ export function createHttpFilter(config: HttpFilterConfig, overrideConfig?: Http
   } else {
     return null;
   }
-}
+}

packages/grpc-js-xds/src/index.ts

@@ -23,6 +23,7 @@ import * as load_balancer_priority from './load-balancer-priority';
 import * as load_balancer_weighted_target from './load-balancer-weighted-target';
 import * as load_balancer_xds_cluster_manager from './load-balancer-xds-cluster-manager';
 import * as xds_wrr_locality from './load-balancer-xds-wrr-locality';
+import * as ring_hash from './load-balancer-ring-hash';
 import * as router_filter from './http-filter/router-filter';
 import * as fault_injection_filter from './http-filter/fault-injection-filter';
 import * as csds from './csds';
@@ -41,6 +42,7 @@ export function register() {
   load_balancer_weighted_target.setup();
   load_balancer_xds_cluster_manager.setup();
   xds_wrr_locality.setup();
+  ring_hash.setup();
   router_filter.setup();
   fault_injection_filter.setup();
   csds.setup();

packages/grpc-js-xds/src/load-balancer-priority.ts

@@ -41,9 +41,26 @@ const DEFAULT_FAILOVER_TIME_MS = 10_000;
 const DEFAULT_RETENTION_INTERVAL_MS = 15 * 60 * 1000;
 
 export interface LocalityEndpoint extends Endpoint {
+  /**
+   * A sequence of strings that determines how to divide endpoints up in priority and
+   * weighted_target.
+   */
   localityPath: string[];
+  /**
+   * The locality this endpoint is in. Used in wrr_locality and xds_cluster_impl.
+   */
   locality: Locality__Output;
-  weight: number;
+  /**
+   * The load balancing weight for the entire locality that contains this
+   * endpoint. Used in xds_wrr_locality.
+   */
+  localityWeight: number;
+  /**
+   * The overall load balancing weight for this endpoint, calculated as the
+   * product of the load balancing weight for this endpoint within its locality
+   * and the load balancing weight of the locality. Used in ring_hash.
+   */
+  endpointWeight: number;
 };
 
 export function isLocalityEndpoint(
@@ -317,7 +334,7 @@ export class PriorityLoadBalancer implements LoadBalancer {
      * so that when the picker calls exitIdle, that in turn calls exitIdle on
      * the PriorityChildImpl, which will start the failover timer. */
     if (state === ConnectivityState.IDLE) {
-      picker = new QueuePicker(this);
+      picker = new QueuePicker(this, picker);
     }
     this.channelControlHelper.updateState(state, picker);
   }