From 54b7d03e0ff0adee3b18ea65af9ac8f849accf47 Mon Sep 17 00:00:00 2001
From: Zach Reyes <39203661+zasweq@users.noreply.github.com>
Date: Fri, 16 Dec 2022 20:02:04 -0500
Subject: [PATCH] grpc: Add join Dial Option (#5861)

---
 default_dial_option_server_option_test.go | 36 +++++++++++++++++++++++
 dialoptions.go                            | 15 ++++++++++
 internal/internal.go                      |  3 ++
 3 files changed, 54 insertions(+)

diff --git a/default_dial_option_server_option_test.go b/default_dial_option_server_option_test.go
index eecd6b846f28..c6cdd7c84838 100644
--- a/default_dial_option_server_option_test.go
+++ b/default_dial_option_server_option_test.go
@@ -80,3 +80,39 @@ func (s) TestAddExtraServerOptions(t *testing.T) {
 		t.Fatalf("Unexpected len of extraServerOptions: %d != 0", len(extraServerOptions))
 	}
 }
+
+// TestJoinDialOption tests the join dial option. It configures a joined dial
+// option with three individual dial options, and verifies that all three are
+// successfully applied.
+func (s) TestJoinDialOption(t *testing.T) {
+	const maxRecvSize = 998765
+	const initialWindowSize = 100
+	jdo := newJoinDialOption(WithTransportCredentials(insecure.NewCredentials()), WithReadBufferSize(maxRecvSize), WithInitialWindowSize(initialWindowSize))
+	cc, err := Dial("fake", jdo)
+	if err != nil {
+		t.Fatalf("Dialing with insecure credentials failed: %v", err)
+	}
+	defer cc.Close()
+	if cc.dopts.copts.ReadBufferSize != maxRecvSize {
+		t.Fatalf("Unexpected cc.dopts.copts.ReadBufferSize: %d != %d", cc.dopts.copts.ReadBufferSize, maxRecvSize)
+	}
+	if cc.dopts.copts.InitialWindowSize != initialWindowSize {
+		t.Fatalf("Unexpected cc.dopts.copts.InitialWindowSize: %d != %d", cc.dopts.copts.InitialWindowSize, initialWindowSize)
+	}
+}
+
+// TestJoinDialOption tests the join server option. It configures a joined
+// server option with three individual server options, and verifies that all
+// three are successfully applied.
+func (s) TestJoinServerOption(t *testing.T) {
+	const maxRecvSize = 998765
+	const initialWindowSize = 100
+	jso := newJoinServerOption(Creds(insecure.NewCredentials()), MaxRecvMsgSize(maxRecvSize), InitialWindowSize(initialWindowSize))
+	s := NewServer(jso)
+	if s.opts.maxReceiveMessageSize != maxRecvSize {
+		t.Fatalf("Unexpected s.opts.maxReceiveMessageSize: %d != %d", s.opts.maxReceiveMessageSize, maxRecvSize)
+	}
+	if s.opts.initialWindowSize != initialWindowSize {
+		t.Fatalf("Unexpected s.opts.initialWindowSize: %d != %d", s.opts.initialWindowSize, initialWindowSize)
+	}
+}
diff --git a/dialoptions.go b/dialoptions.go
index 8f5b536f11eb..4866da101c60 100644
--- a/dialoptions.go
+++ b/dialoptions.go
@@ -44,6 +44,7 @@ func init() {
 		extraDialOptions = nil
 	}
 	internal.WithBinaryLogger = withBinaryLogger
+	internal.JoinDialOptions = newJoinDialOption
 }
 
 // dialOptions configure a Dial call. dialOptions are set by the DialOption
@@ -111,6 +112,20 @@ func newFuncDialOption(f func(*dialOptions)) *funcDialOption {
 	}
 }
 
+type joinDialOption struct {
+	opts []DialOption
+}
+
+func (jdo *joinDialOption) apply(do *dialOptions) {
+	for _, opt := range jdo.opts {
+		opt.apply(do)
+	}
+}
+
+func newJoinDialOption(opts ...DialOption) DialOption {
+	return &joinDialOption{opts: opts}
+}
+
 // WithWriteBufferSize determines how much data can be batched before doing a
 // write on the wire. The corresponding memory allocation for this buffer will
 // be twice the size to keep syscalls low. The default value for this buffer is
diff --git a/internal/internal.go b/internal/internal.go
index fd0ee3dcaf1e..0a76d9de6e02 100644
--- a/internal/internal.go
+++ b/internal/internal.go
@@ -77,6 +77,9 @@ var (
 	// ClearGlobalDialOptions clears the array of extra DialOption. This
 	// method is useful in testing and benchmarking.
 	ClearGlobalDialOptions func()
+	// JoinDialOptions combines the dial options passed as arguments into a
+	// single dial option.
+	JoinDialOptions interface{} // func(...grpc.DialOption) grpc.DialOption
 	// JoinServerOptions combines the server options passed as arguments into a
 	// single server option.
 	JoinServerOptions interface{} // func(...grpc.ServerOption) grpc.ServerOption