Merge branch '1293-re-implement-findbranch-in-go' into 'master'

Re-implemented FindBranch in Go

See merge request gitlab-org/gitaly!981

3 files changed, 47 insertions, 3 deletions

diff --git a/changelogs/unreleased/1293-re-implement-findbranch-in-go.yml b/changelogs/unreleased/1293-re-implement-findbranch-in-go.yml
new file mode 100644
index 000000000..73adc15d6
--- /dev/null
+++ b/changelogs/unreleased/1293-re-implement-findbranch-in-go.yml
@@ -0,0 +1,5 @@
+---
+title: Re-implemented FindBranch in Go
+merge_request: 981
+author:
+type: performance
diff --git a/internal/service/ref/branches.go b/internal/service/ref/branches.go
index 6d03816f7..09aa25189 100644
--- a/internal/service/ref/branches.go
+++ b/internal/service/ref/branches.go
@@ -1,9 +1,17 @@
 package ref
 
 import (
+	"bufio"
+	"io"
+	"strings"
+
 	"gitlab.com/gitlab-org/gitaly-proto/go/gitalypb"
+	"gitlab.com/gitlab-org/gitaly/internal/git"
+	"gitlab.com/gitlab-org/gitaly/internal/git/log"
 	"gitlab.com/gitlab-org/gitaly/internal/rubyserver"
 	"golang.org/x/net/context"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 )
 
 func (s *server) CreateBranch(ctx context.Context, req *gitalypb.CreateBranchRequest) (*gitalypb.CreateBranchResponse, error) {
@@ -35,15 +43,45 @@ func (s *server) DeleteBranch(ctx context.Context, req *gitalypb.DeleteBranchReq
 }
 
 func (s *server) FindBranch(ctx context.Context, req *gitalypb.FindBranchRequest) (*gitalypb.FindBranchResponse, error) {
-	client, err := s.RefServiceClient(ctx)
+	refName := string(req.GetName())
+	if len(refName) == 0 {
+		return nil, status.Errorf(codes.InvalidArgument, "Branch name cannot be empty")
+	}
+	repo := req.GetRepository()
+
+	if strings.HasPrefix(refName, "refs/heads/") {
+		refName = strings.TrimPrefix(refName, "refs/heads/")
+	} else if strings.HasPrefix(refName, "heads/") {
+		refName = strings.TrimPrefix(refName, "heads/")
+	}
+
+	cmd, err := git.Command(ctx, repo, "for-each-ref", "--format", "%(objectname)", "refs/heads/"+refName)
 	if err != nil {
 		return nil, err
 	}
 
-	clientCtx, err := rubyserver.SetHeaders(ctx, req.GetRepository())
+	reader := bufio.NewReader(cmd)
+	revision, _, err := reader.ReadLine()
 	if err != nil {
+		if err == io.EOF {
+			return &gitalypb.FindBranchResponse{}, nil
+		}
+		return nil, err
+	}
+
+	commit, err := log.GetCommit(ctx, repo, string(revision))
+	if err != nil {
+		return nil, err
+	}
+
+	if err := cmd.Wait(); err != nil {
 		return nil, err
 	}
 
-	return client.FindBranch(clientCtx, req)
+	return &gitalypb.FindBranchResponse{
+		Branch: &gitalypb.Branch{
+			Name:         []byte(refName),
+			TargetCommit: commit,
+		},
+	}, nil
 }
diff --git a/ruby/lib/gitaly_server/ref_service.rb b/ruby/lib/gitaly_server/ref_service.rb
index 4c0497cf9..9b3fa036c 100644
--- a/ruby/lib/gitaly_server/ref_service.rb
+++ b/ruby/lib/gitaly_server/ref_service.rb
@@ -44,6 +44,7 @@ module GitalyServer
       raise GRPC::Internal.new(e.to_s)
     end
 
+    # Deprecated: Will be removed in GitLab 11.8
     def find_branch(request, call)
       branch_name = request.name
       raise GRPC::InvalidArgument.new("empty Name") if branch_name.empty?