pubsub: reconnect with old executor (#2498)

pongad · web-flow · commit e5d47b9d27ac · 2017-10-12T10:33:15.000+11:00
We register a callback to reconnect connection when old connection closes. When we shut down the subscriber, we close all connections and begin to shutdown executor. There is a race: if the callback is called after executor closes, an exception occurs and we print a scary stack trace. It doesn't do anything bad; the subscriber is going to go away anyway, but the stack trace is still confusing. This commit avoids registering new jobs on executors. When a connection closes, the callback to determine whether we should reconnect is called in the RPC thread. If the connection closes due to some error, the callback should quickly determine whether we should reconnection. If so, we register the actual reconnection job on a separate thread. This does not block RPC thread, and everyone should be happy. If the connection closes because we're shutting down, the callback running on RPC thread should determine that we should NOT reconnect, not register a reconnection job, and we shouldn't see a stack trace. Fixes #2485.
diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/StreamingSubscriberConnection.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/StreamingSubscriberConnection.java
@@ -250,8 +250,7 @@ public void run() {
                 backoffMillis,
                 TimeUnit.MILLISECONDS);
           }
-        },
-        executor);
+        });
   }
 
   private boolean isAlive() {

Original file line number	Diff line number	Diff line change
`@@ -250,8 +250,7 @@ public void run() {`
`250`	`250`	`backoffMillis,`
`251`	`251`	`TimeUnit.MILLISECONDS);`
`252`	`252`	`}`
`253`		`- },`
`254`		`- executor);`
	`253`	`+ });`
`255`	`254`	`}`
`256`	`255`
`257`	`256`	`private boolean isAlive() {`