adding feature flag for FindAllTags

3 files changed, 83 insertions, 24 deletions

diff --git a/changelogs/unreleased/jc-add-find-all-tags-feature-flag.yml b/changelogs/unreleased/jc-add-find-all-tags-feature-flag.yml
new file mode 100644
index 000000000..f9298b43b
--- /dev/null
+++ b/changelogs/unreleased/jc-add-find-all-tags-feature-flag.yml
@@ -0,0 +1,5 @@
+---
+title: Add feature flag for FindAllTags
+merge_request: 1106
+author:
+type: other
diff --git a/internal/service/ref/refs.go b/internal/service/ref/refs.go
index 1aab6f40d..940b69869 100644
--- a/internal/service/ref/refs.go
+++ b/internal/service/ref/refs.go
@@ -8,6 +8,10 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/prometheus/client_golang/prometheus"
+	"gitlab.com/gitlab-org/gitaly/internal/featureflag"
+	"gitlab.com/gitlab-org/gitaly/internal/rubyserver"
+
 	"gitlab.com/gitlab-org/gitaly-proto/go/gitalypb"
 	"gitlab.com/gitlab-org/gitaly/internal/git"
 	"gitlab.com/gitlab-org/gitaly/internal/git/catfile"
@@ -24,8 +28,22 @@ var (
 	headReference = _headReference
 	// FindBranchNames is exported to be used in other packages
 	FindBranchNames = _findBranchNames
+
+	findAllTagsFeatureFlag = "go-find-all-tags"
+
+	findAllTagsRequests = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "gitaly_find_all_tags_requests_total",
+			Help: "Counter of go vs ruby implementation of FindAllTags",
+		},
+		[]string{"implementation"},
+	)
 )
 
+func init() {
+	prometheus.Register(findAllTagsRequests)
+}
+
 type findRefsOpts struct {
 	cmdArgs []string
 	delim   []byte
@@ -137,11 +155,39 @@ func (s *server) FindAllTags(in *gitalypb.FindAllTagsRequest, stream gitalypb.Re
 		return helper.ErrInvalidArgument(err)
 	}
 
-	if err := parseAndReturnTags(ctx, in.GetRepository(), stream); err != nil {
-		return helper.ErrInternal(err)
+	if featureflag.IsEnabled(ctx, findAllTagsFeatureFlag) {
+		findAllTagsRequests.WithLabelValues("go").Inc()
+		if err := parseAndReturnTags(ctx, in.GetRepository(), stream); err != nil {
+			return helper.ErrInternal(err)
+		}
+		return nil
 	}
 
-	return nil
+	findAllTagsRequests.WithLabelValues("ruby").Inc()
+	client, err := s.RefServiceClient(ctx)
+	if err != nil {
+		return err
+	}
+
+	clientCtx, err := rubyserver.SetHeaders(ctx, in.GetRepository())
+	if err != nil {
+		return err
+	}
+
+	rubyStream, err := client.FindAllTags(clientCtx, in)
+	if err != nil {
+		return err
+	}
+
+	return rubyserver.Proxy(func() error {
+		resp, err := rubyStream.Recv()
+		if err != nil {
+			md := rubyStream.Trailer()
+			stream.SetTrailer(md)
+			return err
+		}
+		return stream.Send(resp)
+	})
 }
 
 func validateFindAllTagsRequest(request *gitalypb.FindAllTagsRequest) error {
diff --git a/internal/service/ref/refs_test.go b/internal/service/ref/refs_test.go
index c4431c376..5db6a232e 100644
--- a/internal/service/ref/refs_test.go
+++ b/internal/service/ref/refs_test.go
@@ -13,11 +13,13 @@ import (
 	"github.com/golang/protobuf/ptypes/timestamp"
 	"github.com/stretchr/testify/require"
 	"gitlab.com/gitlab-org/gitaly-proto/go/gitalypb"
+	"gitlab.com/gitlab-org/gitaly/internal/featureflag"
 	"gitlab.com/gitlab-org/gitaly/internal/git/log"
 	"gitlab.com/gitlab-org/gitaly/internal/git/updateref"
 	"gitlab.com/gitlab-org/gitaly/internal/helper"
 	"gitlab.com/gitlab-org/gitaly/internal/testhelper"
 	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/metadata"
 )
 
 func containsRef(refs [][]byte, ref string) bool {
@@ -489,9 +491,7 @@ func TestSuccessfulFindAllTagsRequest(t *testing.T) {
 	rpcRequest := &gitalypb.FindAllTagsRequest{Repository: testRepoCopy}
 
 	c, err := client.FindAllTags(ctx, rpcRequest)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 
 	var receivedTags []*gitalypb.Tag
 	for {
@@ -499,9 +499,7 @@ func TestSuccessfulFindAllTagsRequest(t *testing.T) {
 		if err == io.EOF {
 			break
 		}
-		if err != nil {
-			t.Fatal(err)
-		}
+		require.NoError(t, err)
 		receivedTags = append(receivedTags, r.GetTags()...)
 	}
 
@@ -570,26 +568,36 @@ func TestSuccessfulFindAllTagsRequest(t *testing.T) {
 		},
 	}
 
-	if len(receivedTags) < len(expectedTags) {
-		t.Fatalf("expected at least %d tags, got %d", len(expectedTags), len(receivedTags))
-	}
+	require.Len(t, receivedTags, len(expectedTags))
 
-	for _, expectedTag := range expectedTags {
-		t.Run(string(expectedTag.Name), func(t *testing.T) {
-			receivedTag := findTag(receivedTags, expectedTag.Name)
-			require.NotNil(t, receivedTag, "tag not found")
-			require.Equal(t, expectedTag, receivedTag)
-		})
+	for i, expectedTag := range expectedTags {
+		require.Equal(t, expectedTag, receivedTags[i])
 	}
-}
 
-func findTag(tags []*gitalypb.Tag, tagName []byte) *gitalypb.Tag {
-	for _, t := range tags {
-		if bytes.Equal(t.Name, tagName) {
-			return t
+	expectedNumberOfTags := len(receivedTags)
+	// using Go implementation
+
+	md := metadata.New(map[string]string{featureflag.HeaderKey(findAllTagsFeatureFlag): "true"})
+	ctx = metadata.NewOutgoingContext(context.Background(), md)
+
+	c, err = client.FindAllTags(ctx, rpcRequest)
+	require.NoError(t, err)
+
+	receivedTags = nil
+	for {
+		r, err := c.Recv()
+		if err == io.EOF {
+			break
 		}
+		require.NoError(t, err)
+		receivedTags = append(receivedTags, r.GetTags()...)
+	}
+
+	require.Len(t, receivedTags, expectedNumberOfTags, "received wrong number of tags")
+
+	for i, expectedTag := range expectedTags {
+		require.Equal(t, expectedTag, receivedTags[i])
 	}
-	return nil
 }
 
 func TestInvalidFindAllTagsRequest(t *testing.T) {