[ package:dds ] Add 30 second keep alive period for SSE connections

Uberproxy actively kills long standing connections after a set period of
time. This change adds a 30 second keep alive period for SSE connections
so connections can be reestablished after being killed by Uberproxy
without DDS assuming the connection has disappeared.

Change-Id: I18363da475bc5d785f85f5ffbec4102a2b7941af
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/183141
Reviewed-by: Gary Roumanis <[email protected]>
Commit-Queue: Ben Konyi <[email protected]>

Author: bkonyi

pkg/dds/CHANGELOG.md

@@ -1,3 +1,6 @@
+# 1.7.5
+- Add 30 second keep alive period for SSE connections.
+
 # 1.7.4
 - Update `package:vm_service` to 6.0.1-nullsafety.0.
 

pkg/dds/lib/src/dds_impl.dart

@@ -231,9 +231,18 @@ class DartDevelopmentServiceImpl implements DartDevelopmentService {
       });
 
   Handler _sseHandler() {
+    // Give connections time to reestablish before considering them closed.
+    // Required to reestablish connections killed by UberProxy.
+    const keepAlive = Duration(seconds: 30);
     final handler = authCodesEnabled
-        ? SseHandler(Uri.parse('/$_authCode/$_kSseHandlerPath'))
-        : SseHandler(Uri.parse('/$_kSseHandlerPath'));
+        ? SseHandler(
+            Uri.parse('/$_authCode/$_kSseHandlerPath'),
+            keepAlive: keepAlive,
+          )
+        : SseHandler(
+            Uri.parse('/$_kSseHandlerPath'),
+            keepAlive: keepAlive,
+          );
 
     handler.connections.rest.listen((sseConnection) {
       final client = DartDevelopmentServiceClient.fromSSEConnection(

pkg/dds/pubspec.yaml

@@ -3,7 +3,7 @@ description: >-
   A library used to spawn the Dart Developer Service, used to communicate with
   a Dart VM Service instance.
 
-version: 1.7.4
+version: 1.7.5
 
 homepage: https://github.com/dart-lang/sdk/tree/master/pkg/dds