Rangediff: Implement RawRangeDiff Service and Range Notation Validationissue_5123_rangediff

Implement the RawRangeDiff function in the rangediff service to process
RangeDiffRequests and send the results back to the client. The revisions
and range notation from the request are validated, with unsupported range
notations returning appropriate errors. An error is also returned when any
revision is empty.

The sendRawOutput function is introduced to execute the provided git.Command
and direct the output to the supplied io.Writer.

Signed-off-by: Siddharth Asthana <siddharthasthana31@gmail.com>

3 files changed, 211 insertions, 0 deletions

diff --git a/internal/gitaly/service/rangediff/rangediff.go b/internal/gitaly/service/rangediff/rangediff.go
new file mode 100644
index 000000000..21409dd4d
--- /dev/null
+++ b/internal/gitaly/service/rangediff/rangediff.go
@@ -0,0 +1,56 @@
+package rangediff
+
+import (
+	"context"
+	"io"
+
+	"gitlab.com/gitlab-org/gitaly/v16/internal/git"
+	"gitlab.com/gitlab-org/gitaly/v16/internal/structerr"
+	"gitlab.com/gitlab-org/gitaly/v16/proto/go/gitalypb"
+	"gitlab.com/gitlab-org/gitaly/v16/streamio"
+)
+
+// RawRangeDiff processes the RangeDiffRequest and sends the result back to the client.
+func (s *server) RawRangeDiff(in *gitalypb.RangeDiffRequest, stream gitalypb.RangeDiffService_RawRangeDiffServer) error {
+	if in.GetRangeNotation() != gitalypb.RangeDiffRequest_TWO_REVS {
+		return structerr.NewInvalidArgument("only TWO_REVS range notation is supported")
+	}
+
+	if !isValidRevision(stream.Context(), in.GetRev1OrRange1()) || !isValidRevision(stream.Context(), in.GetRev2OrRange2()) {
+		return structerr.NewInvalidArgument("revisions are not valid")
+	}
+
+	// Create the range-diff command
+	cmd := git.Command{
+		Name:  "range-diff",
+		Flags: []git.Option{},
+		Args:  []string{in.GetRev1OrRange1(), "...", in.GetRev2OrRange2()},
+	}
+
+	sw := streamio.NewWriter(func(p []byte) error {
+		return stream.Send(&gitalypb.RawRangeDiffResponse{Data: p})
+	})
+
+	return sendRawOutput(stream.Context(), s.gitCmdFactory, in.Repository, sw, cmd)
+}
+
+// sendRawOutput runs the provided git.Command and sends the output to the provided io.Writer.
+func sendRawOutput(ctx context.Context, gitCmdFactory git.CommandFactory, repo *gitalypb.Repository, sender io.Writer, subCmd git.Command) error {
+	cmd, err := gitCmdFactory.New(ctx, repo, subCmd)
+	if err != nil {
+		return structerr.NewInternal("cmd: %w", err)
+	}
+
+	if _, err := io.Copy(sender, cmd); err != nil {
+		return structerr.NewAborted("send: %w", err)
+	}
+
+	return cmd.Wait()
+}
+
+func isValidRevision(ctx context.Context, revision string) bool {
+	if len(revision) == 0 {
+		return false
+	}
+	return true
+}
diff --git a/internal/gitaly/service/rangediff/rangediff_test.go b/internal/gitaly/service/rangediff/rangediff_test.go
new file mode 100644
index 000000000..ece1a09fb
--- /dev/null
+++ b/internal/gitaly/service/rangediff/rangediff_test.go
@@ -0,0 +1,134 @@
+package rangediff
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"gitlab.com/gitlab-org/gitaly/v16/internal/git/gittest"
+	"gitlab.com/gitlab-org/gitaly/v16/internal/gitaly/config"
+	"gitlab.com/gitlab-org/gitaly/v16/internal/gitaly/service"
+	"gitlab.com/gitlab-org/gitaly/v16/internal/structerr"
+	"gitlab.com/gitlab-org/gitaly/v16/internal/testhelper"
+	"gitlab.com/gitlab-org/gitaly/v16/internal/testhelper/testcfg"
+	"gitlab.com/gitlab-org/gitaly/v16/internal/testhelper/testserver"
+	"gitlab.com/gitlab-org/gitaly/v16/proto/go/gitalypb"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+)
+
+func setupRangeDiffService(tb testing.TB, ctx context.Context, opt ...testserver.GitalyServerOpt) (config.Cfg, *gitalypb.Repository, string, gitalypb.RangeDiffServiceClient) {
+	cfg := testcfg.Build(tb)
+
+	addr := testserver.RunGitalyServer(tb, cfg, func(srv *grpc.Server, deps *service.Dependencies) {
+		gitalypb.RegisterRangeDiffServiceServer(srv, NewServer(
+			deps.GetLocator(),
+			deps.GetGitCmdFactory(),
+		))
+	}, opt...)
+	cfg.SocketPath = addr
+
+	conn, err := grpc.Dial(addr, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	require.NoError(tb, err)
+	tb.Cleanup(func() { testhelper.MustClose(tb, conn) })
+
+	client := gitalypb.NewRangeDiffServiceClient(conn)
+
+	repo, repoPath := gittest.CreateRepository(tb, ctx, cfg, gittest.CreateRepositoryConfig{
+		Seed: gittest.SeedGitLabTest,
+	})
+
+	return cfg, repo, repoPath, client
+}
+
+func TestRawRangeDiff_successful(t *testing.T) {
+	t.Parallel()
+
+	ctx := testhelper.Context(t)
+	cfg, repoProto, _, client := setupRangeDiffService(t, ctx)
+	repoProto, _ = gittest.CreateRepository(t, ctx, cfg)
+
+	request := &gitalypb.RangeDiffRequest{
+		Repository:    repoProto,
+		Rev1OrRange1:  "master~2",
+		Rev2OrRange2:  "master",
+		RangeNotation: gitalypb.RangeDiffRequest_TWO_REVS,
+	}
+
+	stream, err := client.RawRangeDiff(ctx, request)
+	require.NoError(t, err)
+
+	var buffer bytes.Buffer
+	writer := io.Writer(&buffer)
+
+	for {
+		resp, err := stream.Recv()
+		if err == io.EOF {
+			break
+		}
+		require.NoError(t, err)
+		_, err = writer.Write(resp.GetData())
+		require.NoError(t, err)
+	}
+}
+
+func TestRawRangeDiff_inputValidation(t *testing.T) {
+	t.Parallel()
+
+	ctx := testhelper.Context(t)
+	cfg, repoProto, _, client := setupRangeDiffService(t, ctx)
+	repoProto, _ = gittest.CreateRepository(t, ctx, cfg)
+
+	tests := []struct {
+		desc        string
+		request     *gitalypb.RangeDiffRequest
+		expectedErr error
+	}{
+		{
+			desc: "empty rev1 or range1",
+			request: &gitalypb.RangeDiffRequest{
+				Repository:    repoProto,
+				Rev2OrRange2:  "master",
+				RangeNotation: gitalypb.RangeDiffRequest_TWO_REVS,
+			},
+			expectedErr: structerr.NewInvalidArgument("revisions cannot be empty"),
+		},
+		{
+			desc: "empty rev2 or range2",
+			request: &gitalypb.RangeDiffRequest{
+				Repository:    repoProto,
+				Rev1OrRange1:  "master~2",
+				RangeNotation: gitalypb.RangeDiffRequest_TWO_REVS,
+			},
+			expectedErr: structerr.NewInvalidArgument("revisions cannot be empty"),
+		},
+		{
+			desc: "unsupported range notation",
+			request: &gitalypb.RangeDiffRequest{
+				Repository:   repoProto,
+				Rev1OrRange1: "master~2",
+				Rev2OrRange2: "master",
+			},
+			expectedErr: structerr.NewInvalidArgument("only TWO_REVS range notation is supported"),
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.desc, func(t *testing.T) {
+			stream, err := client.RawRangeDiff(ctx, tc.request)
+			require.NoError(t, err)
+			err = drainRawRangeDiffResponse(stream)
+			testhelper.RequireGrpcError(t, tc.expectedErr, err)
+		})
+	}
+}
+
+func drainRawRangeDiffResponse(c gitalypb.RangeDiffService_RawRangeDiffClient) error {
+	var err error
+	for err == nil {
+		_, err = c.Recv()
+	}
+	return err
+}
diff --git a/internal/gitaly/service/rangediff/server.go b/internal/gitaly/service/rangediff/server.go
new file mode 100644
index 000000000..c444be16a
--- /dev/null
+++ b/internal/gitaly/service/rangediff/server.go
@@ -0,0 +1,21 @@
+package rangediff
+
+import (
+	"gitlab.com/gitlab-org/gitaly/v16/internal/git"
+	"gitlab.com/gitlab-org/gitaly/v16/internal/gitaly/storage"
+	"gitlab.com/gitlab-org/gitaly/v16/proto/go/gitalypb"
+)
+
+type server struct {
+	gitalypb.UnimplementedRangeDiffServiceServer
+	locator       storage.Locator
+	gitCmdFactory git.CommandFactory
+}
+
+// NewServer creates a new instance of a grpc RangeDiffServiceServer
+func NewServer(locator storage.Locator, gitCmdFactory git.CommandFactory) gitalypb.RangeDiffServiceServer {
+	return &server{
+		locator:       locator,
+		gitCmdFactory: gitCmdFactory,
+	}
+}