From 66e8fc9b629c22417fc7573a499a5abdec713cb2 Mon Sep 17 00:00:00 2001
From: 0SkillAllLuck <43417046+0SkillAllLuck@users.noreply.github.com>
Date: Thu, 18 Mar 2021 18:59:54 +0100
Subject: [PATCH] gRPC LoadBalancingPolicy Support

---
 .../grpc/runtime/config/GrpcClientConfiguration.java        | 6 ++++++
 .../java/io/quarkus/grpc/runtime/supports/Channels.java     | 1 +
 2 files changed, 7 insertions(+)

diff --git a/extensions/grpc/runtime/src/main/java/io/quarkus/grpc/runtime/config/GrpcClientConfiguration.java b/extensions/grpc/runtime/src/main/java/io/quarkus/grpc/runtime/config/GrpcClientConfiguration.java
index 8801f5036e283..0d1f94c7f5eea 100644
--- a/extensions/grpc/runtime/src/main/java/io/quarkus/grpc/runtime/config/GrpcClientConfiguration.java
+++ b/extensions/grpc/runtime/src/main/java/io/quarkus/grpc/runtime/config/GrpcClientConfiguration.java
@@ -137,4 +137,10 @@ public class GrpcClientConfiguration {
     @ConfigItem
     public Optional<String> userAgent;
 
+    /**
+     * Use a custom load balancing policy.
+     * Accepted values are: {@code pick_value}, {@code round_robin}, {@code grpclb}
+     */
+    @ConfigItem(defaultValue = "pick_first")
+    public String loadBalancingPolicy;
 }
diff --git a/extensions/grpc/runtime/src/main/java/io/quarkus/grpc/runtime/supports/Channels.java b/extensions/grpc/runtime/src/main/java/io/quarkus/grpc/runtime/supports/Channels.java
index a9c86fd383ee9..9fe04ee248977 100644
--- a/extensions/grpc/runtime/src/main/java/io/quarkus/grpc/runtime/supports/Channels.java
+++ b/extensions/grpc/runtime/src/main/java/io/quarkus/grpc/runtime/supports/Channels.java
@@ -86,6 +86,7 @@ public static Channel createChannel(String name) throws SSLException {
         }
 
         NettyChannelBuilder builder = NettyChannelBuilder.forAddress(host, port)
+                .defaultLoadBalancingPolicy(config.loadBalancingPolicy)
                 .flowControlWindow(config.flowControlWindow.orElse(DEFAULT_FLOW_CONTROL_WINDOW))
                 .keepAliveWithoutCalls(config.keepAliveWithoutCalls)
                 .maxHedgedAttempts(config.maxHedgedAttempts)