From 31d28b5f147e1392bab22e042aa0282c16a18567 Mon Sep 17 00:00:00 2001
From: Michael Lumish <mlumish@google.com>
Date: Mon, 8 Aug 2022 13:05:26 -0700
Subject: [PATCH] grpc-js: Handle errors when trying to ping

---
 packages/grpc-js/src/subchannel.ts | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/packages/grpc-js/src/subchannel.ts b/packages/grpc-js/src/subchannel.ts
index 5d1bf8973..87c0cd2cd 100644
--- a/packages/grpc-js/src/subchannel.ts
+++ b/packages/grpc-js/src/subchannel.ts
@@ -361,12 +361,21 @@ export class Subchannel {
       this.handleDisconnect();
     }, this.keepaliveTimeoutMs);
     this.keepaliveTimeoutId.unref?.();
-    this.session!.ping(
-      (err: Error | null, duration: number, payload: Buffer) => {
-        this.keepaliveTrace('Received ping response');
-        clearTimeout(this.keepaliveTimeoutId);
-      }
-    );
+    try {
+      this.session!.ping(
+        (err: Error | null, duration: number, payload: Buffer) => {
+          this.keepaliveTrace('Received ping response');
+          clearTimeout(this.keepaliveTimeoutId);
+        }
+      );
+    } catch (e) {
+      /* If we fail to send a ping, the connection is no longer functional, so
+       * we should discard it. */
+      this.transitionToState(
+        [ConnectivityState.READY],
+        ConnectivityState.TRANSIENT_FAILURE
+      );
+    }
   }
 
   private startKeepalivePings() {