grpc-js: Propagate keepalive throttling throughout channel

packages/grpc-js/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@grpc/grpc-js",
-  "version": "1.8.8",
+  "version": "1.8.9",
   "description": "gRPC Library for Node - pure JS implementation",
   "homepage": "https://grpc.io/",
   "repository": "https://github.com/grpc/grpc-node/tree/master/packages/grpc-js",

packages/grpc-js/src/internal-channel.ts

@@ -51,6 +51,7 @@ import { ResolvingCall } from './resolving-call';
 import { getNextCallNumber } from './call-number';
 import { restrictControlPlaneStatusCode } from './control-plane-status';
 import { MessageBufferTracker, RetryingCall, RetryThrottler } from './retrying-call';
+import { BaseSubchannelWrapper, ConnectivityStateListener, SubchannelInterface } from './subchannel-interface';
 
 /**
  * See https://nodejs.org/api/timers.html#timers_setinterval_callback_delay_args
@@ -84,6 +85,33 @@ const RETRY_THROTTLER_MAP: Map<string, RetryThrottler> = new Map();
 const DEFAULT_RETRY_BUFFER_SIZE_BYTES = 1<<24; // 16 MB
 const DEFAULT_PER_RPC_RETRY_BUFFER_SIZE_BYTES = 1<<20; // 1 MB
 
+class ChannelSubchannelWrapper extends BaseSubchannelWrapper implements SubchannelInterface {
+  private stateListeners: ConnectivityStateListener[] = [];
+  private refCount = 0;
+  constructor(childSubchannel: SubchannelInterface, private channel: InternalChannel) {
+    super(childSubchannel);
+    childSubchannel.addConnectivityStateListener((subchannel, previousState, newState, keepaliveTime) => {
+      channel.throttleKeepalive(keepaliveTime);
+      for (const listener of this.stateListeners) {
+        listener(this, previousState, newState, keepaliveTime);
+      }
+    });
+  }
+
+  ref(): void {
+    this.child.ref();
+    this.refCount += 1;
+  }
+
+  unref(): void {
+    this.child.unref();
+    this.refCount -= 1;
+    if (this.refCount <= 0) {
+      this.channel.removeWrappedSubchannel(this);
+    }
+  }
+}
+
 export class InternalChannel {
 
   private resolvingLoadBalancer: ResolvingLoadBalancer;
@@ -116,8 +144,10 @@ export class InternalChannel {
    * configSelector becomes set or the channel state becomes anything other
    * than TRANSIENT_FAILURE.
    */
-   private currentResolutionError: StatusObject | null = null;
-   private retryBufferTracker: MessageBufferTracker;
+  private currentResolutionError: StatusObject | null = null;
+  private retryBufferTracker: MessageBufferTracker;
+  private keepaliveTime: number;
+  private wrappedSubchannels: Set<ChannelSubchannelWrapper> = new Set();
 
   // Channelz info
   private readonly channelzEnabled: boolean = true;
@@ -190,6 +220,7 @@ export class InternalChannel {
       options['grpc.retry_buffer_size'] ?? DEFAULT_RETRY_BUFFER_SIZE_BYTES,
       options['grpc.per_rpc_retry_buffer_size'] ?? DEFAULT_PER_RPC_RETRY_BUFFER_SIZE_BYTES
     );
+    this.keepaliveTime = options['grpc.keepalive_time_ms'] ?? -1;
     const channelControlHelper: ChannelControlHelper = {
       createSubchannel: (
         subchannelAddress: SubchannelAddress,
@@ -201,10 +232,13 @@ export class InternalChannel {
           Object.assign({}, this.options, subchannelArgs),
           this.credentials
         );
+        subchannel.throttleKeepalive(this.keepaliveTime);
         if (this.channelzEnabled) {
           this.channelzTrace.addTrace('CT_INFO', 'Created subchannel or used existing subchannel', subchannel.getChannelzRef());
         }
-        return subchannel;
+        const wrappedSubchannel = new ChannelSubchannelWrapper(subchannel, this);
+        this.wrappedSubchannels.add(wrappedSubchannel);
+        return wrappedSubchannel;
       },
       updateState: (connectivityState: ConnectivityState, picker: Picker) => {
         this.currentPicker = picker;
@@ -369,6 +403,19 @@ export class InternalChannel {
     }
   }
 
+  throttleKeepalive(newKeepaliveTime: number) {
+    if (newKeepaliveTime > this.keepaliveTime) {
+      this.keepaliveTime = newKeepaliveTime;
+      for (const wrappedSubchannel of this.wrappedSubchannels) {
+        wrappedSubchannel.throttleKeepalive(newKeepaliveTime);
+      }
+    }
+  }
+
+  removeWrappedSubchannel(wrappedSubchannel: ChannelSubchannelWrapper) {
+    this.wrappedSubchannels.delete(wrappedSubchannel);
+  }
+
   doPick(metadata: Metadata, extraPickInfo: {[key: string]: string}) {
     return this.currentPicker.pick({metadata: metadata, extraPickInfo: extraPickInfo});
   }

packages/grpc-js/src/load-balancer-outlier-detection.ts

@@ -205,11 +205,11 @@ class OutlierDetectionSubchannelWrapper extends BaseSubchannelWrapper implements
   constructor(childSubchannel: SubchannelInterface, private mapEntry?: MapEntry) {
     super(childSubchannel);
     this.childSubchannelState = childSubchannel.getConnectivityState();
-    childSubchannel.addConnectivityStateListener((subchannel, previousState, newState) => {
+    childSubchannel.addConnectivityStateListener((subchannel, previousState, newState, keepaliveTime) => {
       this.childSubchannelState = newState;
       if (!this.ejected) {
         for (const listener of this.stateListeners) {
-          listener(this, previousState, newState);
+          listener(this, previousState, newState, keepaliveTime);
         }
       }
     });
@@ -265,14 +265,14 @@ class OutlierDetectionSubchannelWrapper extends BaseSubchannelWrapper implements
   eject() {
     this.ejected = true;
     for (const listener of this.stateListeners) {
-      listener(this, this.childSubchannelState, ConnectivityState.TRANSIENT_FAILURE);
+      listener(this, this.childSubchannelState, ConnectivityState.TRANSIENT_FAILURE, -1);
     }
   }
 
   uneject() {
     this.ejected = false;
     for (const listener of this.stateListeners) {
-      listener(this, ConnectivityState.TRANSIENT_FAILURE, this.childSubchannelState);
+      listener(this, ConnectivityState.TRANSIENT_FAILURE, this.childSubchannelState, -1);
     }
   }
 

packages/grpc-js/src/subchannel-interface.ts

@@ -22,7 +22,8 @@ import { Subchannel } from "./subchannel";
 export type ConnectivityStateListener = (
   subchannel: SubchannelInterface,
   previousState: ConnectivityState,
-  newState: ConnectivityState
+  newState: ConnectivityState,
+  keepaliveTime: number
 ) => void;
 
 /**
@@ -40,6 +41,7 @@ export interface SubchannelInterface {
   removeConnectivityStateListener(listener: ConnectivityStateListener): void;
   startConnecting(): void;
   getAddress(): string;
+  throttleKeepalive(newKeepaliveTime: number): void;
   ref(): void;
   unref(): void;
   getChannelzRef(): SubchannelRef;
@@ -67,6 +69,9 @@ export abstract class BaseSubchannelWrapper implements SubchannelInterface {
   getAddress(): string {
     return this.child.getAddress();
   }
+  throttleKeepalive(newKeepaliveTime: number): void {
+    this.child.throttleKeepalive(newKeepaliveTime);
+  }
   ref(): void {
     this.child.ref();
   }

packages/grpc-js/src/subchannel.ts

@@ -64,7 +64,7 @@ export class Subchannel {
 
   private backoffTimeout: BackoffTimeout;
 
-  private keepaliveTimeMultiplier = 1;
+  private keepaliveTime: number;
   /**
    * Tracks channels and subchannel pools with references to this subchannel
    */
@@ -111,6 +111,8 @@ export class Subchannel {
     }, backoffOptions);
     this.subchannelAddressString = subchannelAddressToString(subchannelAddress);
 
+    this.keepaliveTime = options['grpc.keepalive_time_ms'] ?? -1;
+
     if (options['grpc.enable_channelz'] === 0) {
       this.channelzEnabled = false;
     }
@@ -169,7 +171,7 @@ export class Subchannel {
   private startConnectingInternal() {
     let options = this.options;
     if (options['grpc.keepalive_time_ms']) {
-      const adjustedKeepaliveTime = Math.min(options['grpc.keepalive_time_ms'] * this.keepaliveTimeMultiplier, KEEPALIVE_MAX_TIME_MS);
+      const adjustedKeepaliveTime = Math.min(this.keepaliveTime, KEEPALIVE_MAX_TIME_MS);
       options = {...options, 'grpc.keepalive_time_ms': adjustedKeepaliveTime};
     }
     this.connector.connect(this.subchannelAddress, this.credentials, options).then(
@@ -181,14 +183,14 @@ export class Subchannel {
           }
           transport.addDisconnectListener((tooManyPings) => {
             this.transitionToState([ConnectivityState.READY], ConnectivityState.IDLE);
-            if (tooManyPings) {
-              this.keepaliveTimeMultiplier *= 2;
+            if (tooManyPings && this.keepaliveTime > 0) {
+              this.keepaliveTime *= 2;
               logging.log(
                 LogVerbosity.ERROR,
                 `Connection to ${uriToString(this.channelTarget)} at ${
                   this.subchannelAddressString
-                } rejected by server because of excess pings. Increasing ping interval multiplier to ${
-                  this.keepaliveTimeMultiplier
+                } rejected by server because of excess pings. Increasing ping interval to ${
+                  this.keepaliveTime
                 } ms`
               );
             }
@@ -262,7 +264,7 @@ export class Subchannel {
     /* We use a shallow copy of the stateListeners array in case a listener
      * is removed during this iteration */
     for (const listener of [...this.stateListeners]) {
-      listener(this, previousState, newState);
+      listener(this, previousState, newState, this.keepaliveTime);
     }
     return true;
   }
@@ -403,4 +405,10 @@ export class Subchannel {
   getRealSubchannel(): this {
     return this;
   }
+
+  throttleKeepalive(newKeepaliveTime: number) {
+    if (newKeepaliveTime > this.keepaliveTime) {
+      this.keepaliveTime = newKeepaliveTime;
+    }
+  }
 }

packages/grpc-js/src/transport.ts

@@ -77,7 +77,7 @@ class Http2Transport implements Transport {
   /**
    * The amount of time in between sending pings
    */
-  private keepaliveTimeMs: number = KEEPALIVE_MAX_TIME_MS;
+  private keepaliveTimeMs: number = -1;
   /**
    * The amount of time to wait for an acknowledgement after sending a ping
    */
@@ -133,7 +133,7 @@ class Http2Transport implements Transport {
     ]
       .filter((e) => e)
       .join(' '); // remove falsey values first
-
+    
     if ('grpc.keepalive_time_ms' in options) {
       this.keepaliveTimeMs = options['grpc.keepalive_time_ms']!;
     }
@@ -334,6 +334,9 @@ class Http2Transport implements Transport {
   }
 
   private startKeepalivePings() {
+    if (this.keepaliveTimeMs < 0) {
+      return;
+    }
     this.keepaliveIntervalId = setInterval(() => {
       this.sendPing();
     }, this.keepaliveTimeMs);