From 318fef809ac115e509d09a22257c03cd8e2c83c0 Mon Sep 17 00:00:00 2001
From: Eric Anderson <ejona@google.com>
Date: Tue, 18 Jan 2022 12:38:04 -0800
Subject: [PATCH] xds: Handle negative random numbers in c2p resolver

This was noticed because Mockito can't mock Random in Java 17, so it was
replaced with actual Random. But when doing that change it exposed that
negative numbers would cause the id to have a double '-'.
---
 .../java/io/grpc/xds/GoogleCloudToProdNameResolver.java   | 2 +-
 .../io/grpc/xds/GoogleCloudToProdNameResolverTest.java    | 8 +++-----
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/xds/src/main/java/io/grpc/xds/GoogleCloudToProdNameResolver.java b/xds/src/main/java/io/grpc/xds/GoogleCloudToProdNameResolver.java
index 2845d0a00e8..3ec0434a22a 100644
--- a/xds/src/main/java/io/grpc/xds/GoogleCloudToProdNameResolver.java
+++ b/xds/src/main/java/io/grpc/xds/GoogleCloudToProdNameResolver.java
@@ -175,7 +175,7 @@ public void run() {
 
   private ImmutableMap<String, ?> generateBootstrap(String zone, boolean supportIpv6) {
     ImmutableMap.Builder<String, Object> nodeBuilder = ImmutableMap.builder();
-    nodeBuilder.put("id", "C2P-" + rand.nextInt());
+    nodeBuilder.put("id", "C2P-" + (rand.nextInt() & Integer.MAX_VALUE));
     if (!zone.isEmpty()) {
       nodeBuilder.put("locality", ImmutableMap.of("zone", zone));
     }
diff --git a/xds/src/test/java/io/grpc/xds/GoogleCloudToProdNameResolverTest.java b/xds/src/test/java/io/grpc/xds/GoogleCloudToProdNameResolverTest.java
index 58be7108405..7c777b84bf7 100644
--- a/xds/src/test/java/io/grpc/xds/GoogleCloudToProdNameResolverTest.java
+++ b/xds/src/test/java/io/grpc/xds/GoogleCloudToProdNameResolverTest.java
@@ -104,8 +104,7 @@ public void close(Executor instance) {}
 
   @Mock
   private NameResolver.Listener2 mockListener;
-  @Mock
-  private Random mockRandom;
+  private Random random = new Random(1);
   @Captor
   private ArgumentCaptor<Status> errorCaptor;
   private boolean originalIsOnGcp;
@@ -114,7 +113,6 @@ public void close(Executor instance) {}
 
   @Before
   public void setUp() {
-    when(mockRandom.nextInt()).thenReturn(123456789);
     nsRegistry.register(new FakeNsProvider("dns"));
     nsRegistry.register(new FakeNsProvider("xds"));
     originalIsOnGcp = GoogleCloudToProdNameResolver.isOnGcp;
@@ -146,7 +144,7 @@ public HttpURLConnection createConnection(String url) throws IOException {
       }
     };
     resolver = new GoogleCloudToProdNameResolver(
-        TARGET_URI, args, fakeExecutorResource, mockRandom, fakeXdsClientPoolFactory,
+        TARGET_URI, args, fakeExecutorResource, random, fakeXdsClientPoolFactory,
         nsRegistry.asFactory());
     resolver.setHttpConnectionProvider(httpConnections);
   }
@@ -183,7 +181,7 @@ public void onGcpAndNoProvidedBootstrapDelegateToXds() {
     Map<String, ?> bootstrap = fakeXdsClientPoolFactory.bootstrapRef.get();
     Map<String, ?> node = (Map<String, ?>) bootstrap.get("node");
     assertThat(node).containsExactly(
-        "id", "C2P-123456789",
+        "id", "C2P-991614323",
         "locality", ImmutableMap.of("zone", ZONE),
         "metadata", ImmutableMap.of("TRAFFICDIRECTOR_DIRECTPATH_C2P_IPV6_CAPABLE", true));
     Map<String, ?> server = Iterables.getOnlyElement(