grpc-js: Big refactor in preparation for implementing retries

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

@@ -231,7 +231,7 @@ const NUMBER_REGEX = /\d+/;
 let totalActiveFaults = 0;
 
 class FaultInjectionFilter extends BaseFilter implements Filter {
-  constructor(private callStream: CallStream, private config: FaultInjectionConfig) {
+  constructor(private config: FaultInjectionConfig) {
     super();
   }
 
@@ -316,7 +316,7 @@ class FaultInjectionFilter extends BaseFilter implements Filter {
         }
       }
       if (abortStatus !== null && rollRandomPercentage(numerator, denominator)) {
-        this.callStream.cancelWithStatus(abortStatus, 'Fault injected');
+        return Promise.reject({code: abortStatus, details: 'Fault injected', metadata: new Metadata()});
       }
     }
     return metadata;
@@ -333,8 +333,8 @@ class FaultInjectionFilterFactory implements FilterFactory<FaultInjectionFilter>
     }
   }
 
-  createFilter(callStream: experimental.CallStream): FaultInjectionFilter {
-    return new FaultInjectionFilter(callStream, this.config);
+  createFilter(): FaultInjectionFilter {
+    return new FaultInjectionFilter(this.config);
   }
 }
 

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

@@ -26,7 +26,7 @@ class RouterFilter extends BaseFilter implements Filter {}
 class RouterFilterFactory implements FilterFactory<RouterFilter> {
   constructor(config: HttpFilterConfig, overrideConfig?: HttpFilterConfig) {}
 
-  createFilter(callStream: experimental.CallStream): RouterFilter {
+  createFilter(): RouterFilter {
     return new RouterFilter();
   }
 }

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

@@ -146,24 +146,6 @@ export class EdsLoadBalancingConfig implements LoadBalancingConfig {
   }
 }
 
-class CallEndTrackingFilter extends BaseFilter implements Filter {
-  constructor(private onCallEnd: () => void) {
-    super();
-  }
-  receiveTrailers(status: StatusObject) {
-    this.onCallEnd();
-    return status;
-  }
-}
-
-class CallTrackingFilterFactory implements FilterFactory<CallEndTrackingFilter> {
-  constructor(private onCallEnd: () => void) {}
-
-  createFilter(callStream: CallStream) {
-    return new CallEndTrackingFilter(this.onCallEnd);
-  }
-}
-
 /**
  * This class load balances over a cluster by making an EDS request and then
  * transforming the result into a configuration for another load balancing
@@ -217,9 +199,6 @@ export class EdsLoadBalancer implements LoadBalancer {
              * balancer. */
             if (dropCategory === null) {
               const originalPick = originalPicker.pick(pickArgs);
-              const trackingFilterFactory: FilterFactory<Filter> = new CallTrackingFilterFactory(() => {
-                this.concurrentRequests -= 1;
-              });
               return {
                 pickResultType: originalPick.pickResultType,
                 status: originalPick.status,
@@ -228,7 +207,10 @@ export class EdsLoadBalancer implements LoadBalancer {
                   originalPick.onCallStarted?.();
                   this.concurrentRequests += 1;
                 },
-                extraFilterFactories: originalPick.extraFilterFactories.concat(trackingFilterFactory)
+                onCallEnded: status => {
+                  originalPick.onCallEnded?.(status);
+                  this.concurrentRequests -= 1;
+                }
               };
             } else {
               let details: string;
@@ -247,7 +229,7 @@ export class EdsLoadBalancer implements LoadBalancer {
                   metadata: new Metadata(),
                 },
                 subchannel: null,
-                extraFilterFactories: [],
+                onCallEnded: null,
                 onCallStarted: null
               };
             }

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

@@ -108,29 +108,6 @@ export class LrsLoadBalancingConfig implements LoadBalancingConfig {
   }
 }
 
-/**
- * Filter class that reports when the call ends.
- */
-class CallEndTrackingFilter extends BaseFilter implements Filter {
-  constructor(private localityStatsReporter: XdsClusterLocalityStats) {
-    super();
-  }
-
-  receiveTrailers(status: StatusObject) {
-    this.localityStatsReporter.addCallFinished(status.code !== Status.OK);
-    return status;
-  }
-}
-
-class CallEndTrackingFilterFactory
-  implements FilterFactory<CallEndTrackingFilter> {
-  constructor(private localityStatsReporter: XdsClusterLocalityStats) {}
-
-  createFilter(callStream: Call): CallEndTrackingFilter {
-    return new CallEndTrackingFilter(this.localityStatsReporter);
-  }
-}
-
 /**
  * Picker that delegates picking to another picker, and reports when calls
  * created using those picks start and end.
@@ -144,9 +121,6 @@ class LoadReportingPicker implements Picker {
   pick(pickArgs: PickArgs): PickResult {
     const wrappedPick = this.wrappedPicker.pick(pickArgs);
     if (wrappedPick.pickResultType === PickResultType.COMPLETE) {
-      const trackingFilterFactory = new CallEndTrackingFilterFactory(
-        this.localityStatsReporter
-      );
       return {
         pickResultType: PickResultType.COMPLETE,
         subchannel: wrappedPick.subchannel,
@@ -155,7 +129,10 @@ class LoadReportingPicker implements Picker {
           wrappedPick.onCallStarted?.();
           this.localityStatsReporter.addCallStarted();
         },
-        extraFilterFactories: wrappedPick.extraFilterFactories.concat(trackingFilterFactory),
+        onCallEnded: status => {
+          wrappedPick.onCallEnded?.(status);
+          this.localityStatsReporter.addCallFinished(status !== Status.OK);
+        }
       };
     } else {
       return wrappedPick;

packages/grpc-js-xds/src/load-balancer-xds-cluster-manager.ts

@@ -107,8 +107,8 @@ class XdsClusterManagerPicker implements Picker {
           metadata: new Metadata(),
         },
         subchannel: null,
-        extraFilterFactories: [],
-        onCallStarted: null
+        onCallStarted: null,
+        onCallEnded: null
       };
     }
   }