feat(client): add settings for gRPC client

Previously, the client provided WithGRPCDialOptions to configure general gRPC client options.
However, it was challenging to use since there are so many options in gRPC, and hard for users to
know the necessary things.

This PR provides more specific options:

- WithGRPCReadBufferSize
- WithGRPCWriteBufferSize
- WithGRPCInitialConnWindowSize
- WithGRPCInitialWindowSize

It also sets up some options like MaxCallRecvMsgSize and MaxCallSendMsgSize. It uses math.MaxInt32
value for them. Varlog users are not necessarily taken into account the maximum message size limit.

internal/varlogcli/append.go

@@ -9,7 +9,6 @@ import (
 
 	"github.com/pkg/errors"
 	"golang.org/x/sync/errgroup"
-	"google.golang.org/grpc"
 
 	"github.com/kakao/varlog/pkg/types"
 	"github.com/kakao/varlog/pkg/varlog"
@@ -102,10 +101,10 @@ func appendInternal(mrAddrs []string, clusterID types.ClusterID, batchSize int,
 func open(mrAddrs []string, clusterID types.ClusterID) (varlog.Log, error) {
 	ctx, cancel := context.WithTimeout(context.Background(), openTimeout)
 	defer cancel()
-	return varlog.Open(ctx, clusterID, mrAddrs, varlog.WithGRPCDialOptions(
-		grpc.WithReadBufferSize(4*1024*1024),
-		grpc.WithWriteBufferSize(4*1024*1024),
-	))
+	return varlog.Open(ctx, clusterID, mrAddrs,
+		varlog.WithGRPCReadBufferSize(4*1024*1024),
+		varlog.WithGRPCWriteBufferSize(4*1024*1024),
+	)
 }
 
 func scanLoop(ctx context.Context, vlog varlog.Log, ch chan<- []byte) error {

pkg/varlog/options.go

@@ -1,6 +1,7 @@
 package varlog
 
 import (
+	"math"
 	"time"
 
 	"go.uber.org/zap"
@@ -40,8 +41,13 @@ func defaultOptions() options {
 		logger:             zap.NewNop(),
 		grpcDialOptions: []grpc.DialOption{
 			grpc.WithTransportCredentials(insecure.NewCredentials()),
-			grpc.WithReadBufferSize(1 << 20),
-			grpc.WithWriteBufferSize(1 << 20),
+			grpc.WithDefaultCallOptions(
+				// They set the maximum message size the client can read and
+				// write. We use the `math.MaxInt32` for those values, which
+				// are the full size possible.
+				grpc.MaxCallRecvMsgSize(math.MaxInt32),
+				grpc.MaxCallSendMsgSize(math.MaxInt32),
+			),
 		},
 	}
 }
@@ -134,9 +140,43 @@ func WithLogger(logger *zap.Logger) Option {
 	})
 }
 
-func WithGRPCDialOptions(grpcDialOptions ...grpc.DialOption) Option {
+// WithGRPCReadBufferSize sets the size of the gRPC read buffer. Internally, it
+// calls `google.golang.org/grpc.WithReadBufferSize`.
+func WithGRPCReadBufferSize(bytes int) Option {
 	return newOption(func(opts *options) {
-		opts.grpcDialOptions = append(opts.grpcDialOptions, grpcDialOptions...)
+		opts.grpcDialOptions = append(opts.grpcDialOptions,
+			grpc.WithReadBufferSize(bytes),
+		)
+	})
+}
+
+// WithGRPCWriteBufferSize sets the size of the gRPC write buffer. Internally,
+// it calls `google.golang.org/grpc.WithWriteBufferSize`.
+func WithGRPCWriteBufferSize(bytes int) Option {
+	return newOption(func(opts *options) {
+		opts.grpcDialOptions = append(opts.grpcDialOptions,
+			grpc.WithWriteBufferSize(bytes),
+		)
+	})
+}
+
+// WithGRPCInitialConnWindowSize sets the initial window size on a connection.
+// Internally, it calls `google.golang.org/grpc.WithInitialConnWindowSize`.
+func WithGRPCInitialConnWindowSize(bytes int32) Option {
+	return newOption(func(opts *options) {
+		opts.grpcDialOptions = append(opts.grpcDialOptions,
+			grpc.WithInitialConnWindowSize(bytes),
+		)
+	})
+}
+
+// WithGRPCInitialWindowSize sets the initial window size on a stream.
+// Internally, it calls `google.golang.org/grpc.WithInitialWindowSize`.
+func WithGRPCInitialWindowSize(bytes int32) Option {
+	return newOption(func(opts *options) {
+		opts.grpcDialOptions = append(opts.grpcDialOptions,
+			grpc.WithInitialWindowSize(bytes),
+		)
 	})
 }