From 85c7b528e22c300efdc5ae39beccfe54802d9780 Mon Sep 17 00:00:00 2001
From: Jeff Mitchell <jeff@hashicorp.com>
Date: Tue, 6 Feb 2018 13:52:35 -0500
Subject: [PATCH] Change grpc's max sent/recv size to a very large value.
 (#3912)

---
 logical/plugin/grpc_backend.go        | 12 ++++++++++++
 logical/plugin/grpc_backend_client.go |  4 ++--
 logical/plugin/grpc_storage.go        |  6 +++---
 vault/request_forwarding.go           |  7 ++++++-
 4 files changed, 23 insertions(+), 6 deletions(-)
 create mode 100644 logical/plugin/grpc_backend.go

diff --git a/logical/plugin/grpc_backend.go b/logical/plugin/grpc_backend.go
new file mode 100644
index 000000000000..a65eeebeb432
--- /dev/null
+++ b/logical/plugin/grpc_backend.go
@@ -0,0 +1,12 @@
+package plugin
+
+import (
+	"math"
+
+	"google.golang.org/grpc"
+)
+
+var largeMsgGRPCCallOpts []grpc.CallOption = []grpc.CallOption{
+	grpc.MaxCallSendMsgSize(math.MaxInt32),
+	grpc.MaxCallRecvMsgSize(math.MaxInt32),
+}
diff --git a/logical/plugin/grpc_backend_client.go b/logical/plugin/grpc_backend_client.go
index ba7bdbdd88c3..8e584d778d3f 100644
--- a/logical/plugin/grpc_backend_client.go
+++ b/logical/plugin/grpc_backend_client.go
@@ -53,7 +53,7 @@ func (b *backendGRPCPluginClient) HandleRequest(ctx context.Context, req *logica
 
 	reply, err := b.client.HandleRequest(ctx, &pb.HandleRequestArgs{
 		Request: protoReq,
-	})
+	}, largeMsgGRPCCallOpts...)
 	if err != nil {
 		if b.doneCtx.Err() != nil {
 			return nil, ErrPluginShutdown
@@ -115,7 +115,7 @@ func (b *backendGRPCPluginClient) HandleExistenceCheck(ctx context.Context, req
 	defer cancel()
 	reply, err := b.client.HandleExistenceCheck(ctx, &pb.HandleExistenceCheckArgs{
 		Request: protoReq,
-	})
+	}, largeMsgGRPCCallOpts...)
 	if err != nil {
 		if b.doneCtx.Err() != nil {
 			return false, false, ErrPluginShutdown
diff --git a/logical/plugin/grpc_storage.go b/logical/plugin/grpc_storage.go
index b3eb7d28ef67..cfc236877357 100644
--- a/logical/plugin/grpc_storage.go
+++ b/logical/plugin/grpc_storage.go
@@ -25,7 +25,7 @@ type GRPCStorageClient struct {
 func (s *GRPCStorageClient) List(ctx context.Context, prefix string) ([]string, error) {
 	reply, err := s.client.List(ctx, &pb.StorageListArgs{
 		Prefix: prefix,
-	})
+	}, largeMsgGRPCCallOpts...)
 	if err != nil {
 		return reply.Keys, err
 	}
@@ -38,7 +38,7 @@ func (s *GRPCStorageClient) List(ctx context.Context, prefix string) ([]string,
 func (s *GRPCStorageClient) Get(ctx context.Context, key string) (*logical.StorageEntry, error) {
 	reply, err := s.client.Get(ctx, &pb.StorageGetArgs{
 		Key: key,
-	})
+	}, largeMsgGRPCCallOpts...)
 	if err != nil {
 		return nil, err
 	}
@@ -51,7 +51,7 @@ func (s *GRPCStorageClient) Get(ctx context.Context, key string) (*logical.Stora
 func (s *GRPCStorageClient) Put(ctx context.Context, entry *logical.StorageEntry) error {
 	reply, err := s.client.Put(ctx, &pb.StoragePutArgs{
 		Entry: pb.LogicalStorageEntryToProtoStorageEntry(entry),
-	})
+	}, largeMsgGRPCCallOpts...)
 	if err != nil {
 		return err
 	}
diff --git a/vault/request_forwarding.go b/vault/request_forwarding.go
index 7ca4465e4778..687e647763ea 100644
--- a/vault/request_forwarding.go
+++ b/vault/request_forwarding.go
@@ -5,6 +5,7 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
+	math "math"
 	"net"
 	"net/http"
 	"net/url"
@@ -263,7 +264,11 @@ func (c *Core) refreshRequestForwardingConnection(ctx context.Context, clusterAd
 		grpc.WithInsecure(), // it's not, we handle it in the dialer
 		grpc.WithKeepaliveParams(keepalive.ClientParameters{
 			Time: 2 * HeartbeatInterval,
-		}))
+		}),
+		grpc.WithDefaultCallOptions(
+			grpc.MaxCallRecvMsgSize(math.MaxInt32),
+			grpc.MaxCallSendMsgSize(math.MaxInt32),
+		))
 	if err != nil {
 		cancelFunc()
 		c.logger.Error("core: err setting up forwarding rpc client", "error", err)