prevent running reconcile with repository specific primaries

`praefect reconcile` command is unnecessary with repository specific
primaries and doesn't work together with them. There are few reasons
for this:

1. When repository specific primaries are enabled, Praefect expects
   to have database records for every repository. As such, the automatic
   reconciler can already perform all of the reconciling the manual command
   would do. This makes the manual command unnecessary.

2. The manual command works on the level of a storage. Running the command
   would very likely result in jobs from secondaries to the primaries. While
   this is not harmful as Praefect has checks against downgrading, we should
   not produce such jobs.

3. Reconcile automatically figures out the primary of the virtual storage and
   uses it as the reference storage. This is not a good approach as the primary
   might not even be up to date. More so, there is no single primary when
   repository specific primaries are enabled.

Due to the above points, the reconcile subcommand is not needed when repository
specific primaries are enabled. While we should keep it around for backwards
compatibility as long as virtual storage scoped primaries can be enabled, we should
prevent it from being used with repository specific primaries.

2 files changed, 20 insertions, 0 deletions

diff --git a/internal/praefect/service/info/consistencycheck.go b/internal/praefect/service/info/consistencycheck.go
index 1f1b0c399..3d7848768 100644
--- a/internal/praefect/service/info/consistencycheck.go
+++ b/internal/praefect/service/info/consistencycheck.go
@@ -7,6 +7,7 @@ import (
 
 	"gitlab.com/gitlab-org/gitaly/internal/helper"
 	"gitlab.com/gitlab-org/gitaly/internal/middleware/metadatahandler"
+	"gitlab.com/gitlab-org/gitaly/internal/praefect/config"
 	"gitlab.com/gitlab-org/gitaly/internal/praefect/datastore"
 	"gitlab.com/gitlab-org/gitaly/internal/praefect/nodes"
 	"gitlab.com/gitlab-org/gitaly/proto/go/gitalypb"
@@ -16,9 +17,15 @@ import (
 	"google.golang.org/grpc/status"
 )
 
+var errRepositorySpecificPrimariesUnsupported = status.Error(codes.FailedPrecondition, "`praefect reconcile` should not be used with repository specific primaries enabled. Please enable automatic reconciler instead.")
+
 var errReconciliationInternal = errors.New("internal error(s) occurred during execution")
 
 func (s *Server) validateConsistencyCheckRequest(req *gitalypb.ConsistencyCheckRequest) error {
+	if s.conf.Failover.ElectionStrategy == config.ElectionStrategyPerRepository {
+		return errRepositorySpecificPrimariesUnsupported
+	}
+
 	if req.GetTargetStorage() == "" {
 		return status.Error(codes.InvalidArgument, "missing target storage")
 	}
@@ -32,6 +39,7 @@ func (s *Server) validateConsistencyCheckRequest(req *gitalypb.ConsistencyCheckR
 			req.GetTargetStorage(), req.GetReferenceStorage(),
 		)
 	}
+
 	return nil
 }
 
diff --git a/internal/praefect/service/info/consistencycheck_test.go b/internal/praefect/service/info/consistencycheck_test.go
index e9266784c..2a77e7d0f 100644
--- a/internal/praefect/service/info/consistencycheck_test.go
+++ b/internal/praefect/service/info/consistencycheck_test.go
@@ -28,6 +28,18 @@ import (
 	"google.golang.org/grpc/status"
 )
 
+func TestServer_ConsistencyCheck_repositorySpecificPrimariesUnsupported(t *testing.T) {
+	require.Equal(
+		t,
+		errRepositorySpecificPrimariesUnsupported,
+		NewServer(nil,
+			config.Config{
+				Failover: config.Failover{ElectionStrategy: config.ElectionStrategyPerRepository},
+			}, nil, nil, nil,
+		).ConsistencyCheck(nil, nil),
+	)
+}
+
 func TestServer_ConsistencyCheck(t *testing.T) {
 	cfg := gconfig.Config