fixes CRDB datastore not reporting proper GRPC codes

- duplicate relationship now reports gRPC code AlreadyExists
- retryable errors now return grpc code Unavailable

internal/datastore/crdb/crdb.go

@@ -336,12 +336,21 @@ func (cds *crdbDatastore) ReadWriteTx(
 		return nil
 	})
 	if err != nil {
-		return datastore.NoRevision, err
+		return datastore.NoRevision, wrapError(err)
 	}
 
 	return commitTimestamp, nil
 }
 
+func wrapError(err error) error {
+	// If a unique constraint violation is returned, then its likely that the cause
+	// was an existing relationship.
+	if cerr := pgxcommon.ConvertToWriteConstraintError(livingTupleConstraint, err); cerr != nil {
+		return cerr
+	}
+	return err
+}
+
 func (cds *crdbDatastore) ReadyState(ctx context.Context) (datastore.ReadyState, error) {
 	headMigration, err := migrations.CRDBMigrations.HeadRevision()
 	if err != nil {

internal/datastore/crdb/pool/slqerrors.go

@@ -4,7 +4,12 @@ import (
 	"errors"
 	"fmt"
 
+	v1 "github.com/authzed/authzed-go/proto/authzed/api/v1"
 	"github.com/jackc/pgx/v5/pgconn"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	"github.com/authzed/spicedb/pkg/spiceerrors"
 )
 
 const (
@@ -35,6 +40,15 @@ func (e *MaxRetryError) Error() string {
 
 func (e *MaxRetryError) Unwrap() error { return e.LastErr }
 
+func (e *MaxRetryError) GRPCStatus() *status.Status {
+	s, ok := status.FromError(e.Unwrap())
+	if !ok {
+		return nil
+	}
+
+	return s
+}
+
 // ResettableError is an error that we think may succeed if retried against a new connection.
 type ResettableError struct {
 	Err error
@@ -43,6 +57,17 @@ type ResettableError struct {
 func (e *ResettableError) Error() string { return "resettable error" + ": " + e.Err.Error() }
 func (e *ResettableError) Unwrap() error { return e.Err }
 
+func (e *ResettableError) GRPCStatus() *status.Status {
+	return spiceerrors.WithCodeAndDetails(
+		e.Unwrap(),
+		codes.Unavailable, // return unavailable so clients are know it's ok to retry
+		spiceerrors.ForReason(
+			v1.ErrorReason_ERROR_REASON_UNSPECIFIED, // FIXME provide a more specific reason
+			map[string]string{},
+		),
+	)
+}
+
 // RetryableError is an error that can be retried against the existing connection.
 type RetryableError struct {
 	Err error
@@ -51,6 +76,17 @@ type RetryableError struct {
 func (e *RetryableError) Error() string { return "retryable error" + ": " + e.Err.Error() }
 func (e *RetryableError) Unwrap() error { return e.Err }
 
+func (e *RetryableError) GRPCStatus() *status.Status {
+	return spiceerrors.WithCodeAndDetails(
+		e.Unwrap(),
+		codes.Unavailable, // return unavailable so clients are know it's ok to retry
+		spiceerrors.ForReason(
+			v1.ErrorReason_ERROR_REASON_UNSPECIFIED, // FIXME provide a more specific reason
+			map[string]string{},
+		),
+	)
+}
+
 // sqlErrorCode attempts to extract the crdb error code from the error state.
 func sqlErrorCode(err error) string {
 	var pgerr *pgconn.PgError

pkg/datastore/test/tuples.go

@@ -566,6 +566,14 @@ func CreateAlreadyExistingTest(t *testing.T, tester DatastoreTester) {
 	require.ErrorAs(err, &common.CreateRelationshipExistsError{})
 	require.Contains(err.Error(), "could not CREATE relationship ")
 	grpcutil.RequireStatus(t, codes.AlreadyExists, err)
+
+	f := func(ctx context.Context, rwt datastore.ReadWriteTransaction) error {
+		_, err := rwt.BulkLoad(ctx, testfixtures.NewBulkTupleGenerator(testResourceNamespace, testReaderRelation, testUserNamespace, 1, t))
+		return err
+	}
+	_, _ = ds.ReadWriteTx(ctx, f)
+	_, err = ds.ReadWriteTx(ctx, f)
+	grpcutil.RequireStatus(t, codes.AlreadyExists, err)
 }
 
 // TouchAlreadyExistingTest tests touching a relationship twice.