Merge pull request #1612 from murgatroid99/grpc-js_keepalive_without_calls

grpc-js: Add support for grpc.keepalive_permit_without_calls channel arg

PACKAGE-COMPARISON.md

@@ -36,6 +36,7 @@ In addition, all channel arguments defined in [this header file](https://github.
  - `grpc.default_authority`
  - `grpc.keepalive_time_ms`
  - `grpc.keepalive_timeout_ms`
+ - `grpc.keepalive_permit_without_calls`
  - `grpc.service_config`
  - `grpc.max_concurrent_streams`
  - `grpc.initial_reconnect_backoff_ms`

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

@@ -25,6 +25,7 @@ export interface ChannelOptions {
   'grpc.default_authority'?: string;
   'grpc.keepalive_time_ms'?: number;
   'grpc.keepalive_timeout_ms'?: number;
+  'grpc.keepalive_permit_without_calls'?: number;
   'grpc.service_config'?: string;
   'grpc.max_concurrent_streams'?: number;
   'grpc.initial_reconnect_backoff_ms'?: number;
@@ -49,6 +50,7 @@ export const recognizedOptions = {
   'grpc.default_authority': true,
   'grpc.keepalive_time_ms': true,
   'grpc.keepalive_timeout_ms': true,
+  'grpc.keepalive_permit_without_calls': true,
   'grpc.service_config': true,
   'grpc.max_concurrent_streams': true,
   'grpc.initial_reconnect_backoff_ms': true,

packages/grpc-js/src/subchannel.ts

@@ -180,6 +180,10 @@ export class Subchannel {
    * Timer reference tracking when the most recent ping will be considered lost
    */
   private keepaliveTimeoutId: NodeJS.Timer;
+  /**
+   * Indicates whether keepalive pings should be sent without any active calls
+   */
+  private keepaliveWithoutCalls: boolean = false;
 
   /**
    * Tracks calls with references to this subchannel
@@ -226,6 +230,11 @@ export class Subchannel {
     if ('grpc.keepalive_timeout_ms' in options) {
       this.keepaliveTimeoutMs = options['grpc.keepalive_timeout_ms']!;
     }
+    if ('grpc.keepalive_permit_without_calls' in options) {
+      this.keepaliveWithoutCalls = options['grpc.keepalive_permit_without_calls'] === 1;
+    } else {
+      this.keepaliveWithoutCalls = false;
+    }
     this.keepaliveIntervalId = setTimeout(() => {}, 0);
     clearTimeout(this.keepaliveIntervalId);
     this.keepaliveTimeoutId = setTimeout(() => {}, 0);
@@ -532,6 +541,9 @@ export class Subchannel {
             listener();
           }
         });
+        if (this.keepaliveWithoutCalls) {
+          this.startKeepalivePings();
+        }
         break;
       case ConnectivityState.CONNECTING:
         this.startBackoff();
@@ -602,7 +614,9 @@ export class Subchannel {
       if (this.session) {
         this.session.ref();
       }
-      this.startKeepalivePings();
+      if (!this.keepaliveWithoutCalls) {
+        this.startKeepalivePings();
+      }
     }
     this.callRefcount += 1;
   }
@@ -620,7 +634,9 @@ export class Subchannel {
       if (this.session) {
         this.session.unref();
       }
-      this.stopKeepalivePings();
+      if (!this.keepaliveWithoutCalls) {
+        this.stopKeepalivePings();
+      }
       this.checkBothRefcounts();
     }
   }