additional changes to ensure sameness groups without DefaultForFailover can be used for DNS (#21107)

agent/dns.go

@@ -1096,9 +1096,10 @@ func rCodeFromError(err error) int {
 		return dns.RcodeSuccess
 	case errors.Is(err, errECSNotGlobal):
 		return rCodeFromError(errors.Unwrap(err))
-	case errors.Is(err, errNameNotFound):
+	case errors.Is(err, errNameNotFound),
-		return dns.RcodeNameError
+		structs.IsErrNoDCPath(err),
-	case structs.IsErrNoDCPath(err) || structs.IsErrQueryNotFound(err):
+		structs.IsErrQueryNotFound(err),
+		structs.IsErrSamenessGroupMustBeDefaultForFailover(err):
 		return dns.RcodeNameError
 	default:
 		return dns.RcodeServerFailure

agent/dns/discovery_results_fetcher.go

@@ -69,6 +69,9 @@ func (d discoveryResultsFetcher) getQueryResults(opts *getQueryOptions) ([]*disc
 
 		if getErrorFromECSNotGlobalError(err) != nil {
 			opts.logger.Error("error processing discovery query", "error", err)
+			if structs.IsErrSamenessGroupMustBeDefaultForFailover(err) {
+				return nil, query, errNameNotFound
+			}
 			return nil, query, err
 		}
 		return results, query, err

agent/health_endpoint_test.go

@@ -834,9 +834,6 @@ func testHealthServiceNodes(t *testing.T, backendCfg *queryBackendConfiguration)
 				_, err = strconv.ParseUint(header, 10, 64)
 				require.NoError(r, err)
 
-				// Should be a cache hit! The data should've updated in the cache
-				// in the background so this should've been fetched directly from
-				// the cache.
 				if backendCfg.cached {
 					// Should be a cache hit! The data should've updated in the cache
 					// in the background so this should've been fetched directly from
@@ -1763,6 +1760,8 @@ func testHealthConnectServiceNodes(t *testing.T, backendCfg *queryBackendConfigu
 	nodes := obj.(structs.CheckServiceNodes)
 	assert.Len(t, nodes, 1)
 	assert.Len(t, nodes[0].Checks, 0)
+
+	require.Equal(t, backendCfg.queryBackend, resp.Header().Get("X-Consul-Query-Backend"))
 }
 
 func TestHealthIngressServiceNodes(t *testing.T) {
@@ -2021,7 +2020,6 @@ func testHealthConnectServiceNodes_PassingFilter(t *testing.T, backendCfg *query
 		// Should be 1
 		nodes := obj.(structs.CheckServiceNodes)
 		assert.Len(t, nodes, 1)
-
 		require.Equal(t, backendCfg.queryBackend, resp.Header().Get("X-Consul-Query-Backend"))
 	})
 

agent/structs/errors.go

@@ -9,38 +9,40 @@ import (
 )
 
 const (
-	errNoLeader                   = "No cluster leader"
+	errNoLeader                              = "No cluster leader"
-	errNoDCPath                   = "No path to datacenter"
+	errNoDCPath                              = "No path to datacenter"
-	errDCNotAvailable             = "Remote DC has no server currently reachable"
+	errDCNotAvailable                        = "Remote DC has no server currently reachable"
-	errNoServers                  = "No known Consul servers"
+	errNoServers                             = "No known Consul servers"
-	errNotReadyForConsistentReads = "Not ready to serve consistent reads"
+	errNotReadyForConsistentReads            = "Not ready to serve consistent reads"
-	errSegmentsNotSupported       = "Network segments are not supported in this version of Consul"
+	errSegmentsNotSupported                  = "Network segments are not supported in this version of Consul"
-	errRPCRateExceeded            = "RPC rate limit exceeded"
+	errRPCRateExceeded                       = "RPC rate limit exceeded"
-	errServiceNotFound            = "Service not found: "
+	errServiceNotFound                       = "Service not found: "
-	errQueryNotFound              = "Query not found"
+	errQueryNotFound                         = "Query not found"
-	errLeaderNotTracked           = "Raft leader not found in server lookup mapping"
+	errLeaderNotTracked                      = "Raft leader not found in server lookup mapping"
-	errConnectNotEnabled          = "Connect must be enabled in order to use this endpoint"
+	errConnectNotEnabled                     = "Connect must be enabled in order to use this endpoint"
-	errRateLimited                = "Rate limit reached, try again later" // Note: we depend on this error message in the gRPC ConnectCA.Sign endpoint (see: isRateLimitError).
+	errRateLimited                           = "Rate limit reached, try again later" // Note: we depend on this error message in the gRPC ConnectCA.Sign endpoint (see: isRateLimitError).
-	errNotPrimaryDatacenter       = "not the primary datacenter"
+	errNotPrimaryDatacenter                  = "not the primary datacenter"
-	errStateReadOnly              = "CA Provider State is read-only"
+	errStateReadOnly                         = "CA Provider State is read-only"
-	errUsingV2CatalogExperiment   = "V1 catalog is disabled when V2 is enabled"
+	errUsingV2CatalogExperiment              = "V1 catalog is disabled when V2 is enabled"
+	errSamenessGroupMustBeDefaultForFailover = "Sameness Group must have DefaultForFailover set to true in order to use this endpoint"
 )
 
 var (
-	ErrNoLeader                   = errors.New(errNoLeader)
+	ErrNoLeader                              = errors.New(errNoLeader)
-	ErrNoDCPath                   = errors.New(errNoDCPath)
+	ErrNoDCPath                              = errors.New(errNoDCPath)
-	ErrNoServers                  = errors.New(errNoServers)
+	ErrNoServers                             = errors.New(errNoServers)
-	ErrNotReadyForConsistentReads = errors.New(errNotReadyForConsistentReads)
+	ErrNotReadyForConsistentReads            = errors.New(errNotReadyForConsistentReads)
-	ErrSegmentsNotSupported       = errors.New(errSegmentsNotSupported)
+	ErrSegmentsNotSupported                  = errors.New(errSegmentsNotSupported)
-	ErrRPCRateExceeded            = errors.New(errRPCRateExceeded)
+	ErrRPCRateExceeded                       = errors.New(errRPCRateExceeded)
-	ErrDCNotAvailable             = errors.New(errDCNotAvailable)
+	ErrDCNotAvailable                        = errors.New(errDCNotAvailable)
-	ErrQueryNotFound              = errors.New(errQueryNotFound)
+	ErrQueryNotFound                         = errors.New(errQueryNotFound)
-	ErrLeaderNotTracked           = errors.New(errLeaderNotTracked)
+	ErrLeaderNotTracked                      = errors.New(errLeaderNotTracked)
-	ErrConnectNotEnabled          = errors.New(errConnectNotEnabled)
+	ErrConnectNotEnabled                     = errors.New(errConnectNotEnabled)
-	ErrRateLimited                = errors.New(errRateLimited) // Note: we depend on this error message in the gRPC ConnectCA.Sign endpoint (see: isRateLimitError).
+	ErrRateLimited                           = errors.New(errRateLimited) // Note: we depend on this error message in the gRPC ConnectCA.Sign endpoint (see: isRateLimitError).
-	ErrNotPrimaryDatacenter       = errors.New(errNotPrimaryDatacenter)
+	ErrNotPrimaryDatacenter                  = errors.New(errNotPrimaryDatacenter)
-	ErrStateReadOnly              = errors.New(errStateReadOnly)
+	ErrStateReadOnly                         = errors.New(errStateReadOnly)
-	ErrUsingV2CatalogExperiment   = errors.New(errUsingV2CatalogExperiment)
+	ErrUsingV2CatalogExperiment              = errors.New(errUsingV2CatalogExperiment)
+	ErrSamenessGroupMustBeDefaultForFailover = errors.New(errSamenessGroupMustBeDefaultForFailover)
 )
 
 func IsErrNoDCPath(err error) bool {
@@ -59,10 +61,10 @@ func IsErrRPCRateExceeded(err error) bool {
 	return err != nil && strings.Contains(err.Error(), errRPCRateExceeded)
 }
 
-func IsErrServiceNotFound(err error) bool {
-	return err != nil && strings.Contains(err.Error(), errServiceNotFound)
-}
-
 func IsErrUsingV2CatalogExperiment(err error) bool {
 	return err != nil && strings.Contains(err.Error(), errUsingV2CatalogExperiment)
 }
+
+func IsErrSamenessGroupMustBeDefaultForFailover(err error) bool {
+	return err != nil && strings.Contains(err.Error(), errSamenessGroupMustBeDefaultForFailover)
+}