add sameness group support to service resolver failover and redirects (#16664)

agent/configentry/discoverychain.go

@@ -15,6 +15,7 @@ type DiscoveryChainSet struct {
 	Resolvers      map[structs.ServiceID]*structs.ServiceResolverConfigEntry
 	Services       map[structs.ServiceID]*structs.ServiceConfigEntry
 	Peers          map[string]*pbpeering.Peering
+	SamenessGroups map[string]*structs.SamenessGroupConfigEntry
 	ProxyDefaults  map[string]*structs.ProxyConfigEntry
 }
 
@@ -26,6 +27,7 @@ func NewDiscoveryChainSet() *DiscoveryChainSet {
 		Services:       make(map[structs.ServiceID]*structs.ServiceConfigEntry),
 		Peers:          make(map[string]*pbpeering.Peering),
 		ProxyDefaults:  make(map[string]*structs.ProxyConfigEntry),
+		SamenessGroups: make(map[string]*structs.SamenessGroupConfigEntry),
 	}
 }
 

agent/consul/state/config_entry.go

@@ -1301,6 +1301,7 @@ func readDiscoveryChainConfigEntriesTxn(
 		todoResolvers      = make(map[structs.ServiceID]struct{})
 		todoDefaults       = make(map[structs.ServiceID]struct{})
 		todoPeers          = make(map[string]struct{})
+		todoSamenessGroups = make(map[string]struct{})
 	)
 
 	sid := structs.NewServiceID(serviceName, entMeta)
@@ -1406,6 +1407,10 @@ func readDiscoveryChainConfigEntriesTxn(
 		for _, peer := range resolver.RelatedPeers() {
 			todoPeers[peer] = struct{}{}
 		}
+
+		for _, peer := range resolver.RelatedSamenessGroups() {
+			todoSamenessGroups[peer] = struct{}{}
+		}
 	}
 
 	for {
@@ -1448,6 +1453,26 @@ func readDiscoveryChainConfigEntriesTxn(
 	}
 
 	peerEntMeta := structs.DefaultEnterpriseMetaInPartition(entMeta.PartitionOrDefault())
+	for sg := range todoSamenessGroups {
+		idx, entry, err := getSamenessGroupConfigEntryTxn(tx, ws, sg, overrides, peerEntMeta)
+		if err != nil {
+			return 0, nil, err
+		}
+		if idx > maxIdx {
+			maxIdx = idx
+		}
+		if entry == nil {
+			continue
+		}
+
+		for _, e := range entry.Members {
+			if e.Peer != "" {
+				todoPeers[e.Peer] = struct{}{}
+			}
+		}
+		res.SamenessGroups[sg] = entry
+	}
+
 	for peerName := range todoPeers {
 		q := Query{
 			Value:          peerName,

agent/consul/state/config_entry_sameness_group_oss.go

@@ -6,6 +6,8 @@ package state
 import (
 	"fmt"
 
+	"github.com/hashicorp/consul/acl"
+	"github.com/hashicorp/consul/agent/configentry"
 	"github.com/hashicorp/consul/agent/structs"
 	"github.com/hashicorp/go-memdb"
 )
@@ -27,3 +29,19 @@ func (*SamenessGroupDefaultIndex) FromArgs(args ...interface{}) ([]byte, error)
 func checkSamenessGroup(tx ReadTxn, newConfig structs.ConfigEntry) error {
 	return fmt.Errorf("sameness-groups are an enterprise-only feature")
 }
+
+// getExportedServicesConfigEntryTxn is a convenience method for fetching a
+// sameness-group config entries.
+//
+// If an override KEY is present for the requested config entry, the index
+// returned will be 0. Any override VALUE (nil or otherwise) will be returned
+// if there is a KEY match.
+func getSamenessGroupConfigEntryTxn(
+	tx ReadTxn,
+	ws memdb.WatchSet,
+	name string,
+	overrides map[configentry.KindName]structs.ConfigEntry,
+	entMeta *acl.EnterpriseMeta,
+) (uint64, *structs.SamenessGroupConfigEntry, error) {
+	return 0, nil, nil
+}

agent/structs/config_entry_discoverychain.go

@@ -1053,6 +1053,12 @@ func (e *ServiceResolverConfigEntry) Validate() error {
 		}
 
 		switch {
+		case r.SamenessGroup != "" && r.ServiceSubset != "":
+			return fmt.Errorf("Redirect.SamenessGroup cannot be set with Redirect.ServiceSubset")
+		case r.SamenessGroup != "" && r.Partition != "":
+			return fmt.Errorf("Redirect.Partition cannot be set with Redirect.SamenessGroup")
+		case r.SamenessGroup != "" && r.Datacenter != "":
+			return fmt.Errorf("Redirect.SamenessGroup cannot be set with Redirect.Datacenter")
 		case r.Peer != "" && r.ServiceSubset != "":
 			return fmt.Errorf("Redirect.Peer cannot be set with Redirect.ServiceSubset")
 		case r.Peer != "" && r.Partition != "":
@@ -1116,6 +1122,17 @@ func (e *ServiceResolverConfigEntry) Validate() error {
 				}
 			}
 
+			if f.SamenessGroup != "" {
+				switch {
+				case len(f.Datacenters) > 0:
+					return fmt.Errorf("Bad Failover[%q]: SamenessGroup cannot be set with Datacenters", subset)
+				case f.ServiceSubset != "":
+					return fmt.Errorf("Bad Failover[%q]: SamenessGroup cannot be set with ServiceSubset", subset)
+				case len(f.Targets) > 0:
+					return fmt.Errorf("Bad Failover[%q]: SamenessGroup cannot be set with Targets", subset)
+				}
+			}
+
 			if len(f.Datacenters) != 0 && len(f.Targets) != 0 {
 				return fmt.Errorf("Bad Failover[%q]: Targets cannot be set with Datacenters", subset)
 			}
@@ -1341,6 +1358,10 @@ type ServiceResolverRedirect struct {
 	// Peer is the name of the cluster peer to resolve the service from instead
 	// of the current one (optional).
 	Peer string `json:",omitempty"`
+
+	// SamenessGroup is the name of the sameness group to resolve the service from instead
+	// of the local partition.
+	SamenessGroup string `json:",omitempty"`
 }
 
 func (r *ServiceResolverRedirect) ToDiscoveryTargetOpts() DiscoveryTargetOpts {
@@ -1355,7 +1376,13 @@ func (r *ServiceResolverRedirect) ToDiscoveryTargetOpts() DiscoveryTargetOpts {
 }
 
 func (r *ServiceResolverRedirect) isEmpty() bool {
-	return r.Service == "" && r.ServiceSubset == "" && r.Namespace == "" && r.Partition == "" && r.Datacenter == "" && r.Peer == ""
+	return r.Service == "" &&
+		r.ServiceSubset == "" &&
+		r.Namespace == "" &&
+		r.Partition == "" &&
+		r.Datacenter == "" &&
+		r.Peer == "" &&
+		r.SamenessGroup == ""
 }
 
 // There are some restrictions on what is allowed in here:
@@ -1400,6 +1427,9 @@ type ServiceResolverFailover struct {
 
 	// Policy specifies the exact mechanism used for failover.
 	Policy *ServiceResolverFailoverPolicy `json:",omitempty"`
+
+	// SamenessGroup specifies the sameness group to failover to.
+	SamenessGroup string `json:",omitempty"`
 }
 
 type ServiceResolverFailoverPolicy struct {

agent/structs/config_entry_discoverychain_oss.go

@@ -38,6 +38,10 @@ func (redir *ServiceResolverRedirect) ValidateEnterprise() error {
 		return fmt.Errorf("Setting Namespace requires Consul Enterprise")
 	}
 
+	if redir.SamenessGroup != "" {
+		return fmt.Errorf("Setting SamenessGroup requires Consul Enterprise")
+	}
+
 	return nil
 }
 
@@ -54,6 +58,10 @@ func (failover *ServiceResolverFailover) ValidateEnterprise() error {
 		return fmt.Errorf("Setting Namespace requires Consul Enterprise")
 	}
 
+	if failover.SamenessGroup != "" {
+		return fmt.Errorf("Setting SamenessGroup requires Consul Enterprise")
+	}
+
 	return nil
 }
 
@@ -102,3 +110,8 @@ func (f *ServiceResolverFailoverPolicy) ValidateEnterprise() error {
 
 	return nil
 }
+
+// RelatedSamenessGroups doesn't return anything on open source.
+func (e *ServiceResolverConfigEntry) RelatedSamenessGroups() []string {
+	return nil
+}

agent/structs/config_entry_discoverychain_oss_test.go

@@ -21,6 +21,19 @@ func TestServiceResolverConfigEntry_OSS(t *testing.T) {
 	}
 
 	cases := []testcase{
+		{
+			name: "failover with a sameness group on OSS",
+			entry: &ServiceResolverConfigEntry{
+				Kind: ServiceResolver,
+				Name: "test",
+				Failover: map[string]ServiceResolverFailover{
+					"*": {
+						SamenessGroup: "ns1",
+					},
+				},
+			},
+			validateErr: `Bad Failover["*"]: Setting SamenessGroup requires Consul Enterprise`,
+		},
 		{
 			name: "failover with a namespace on OSS",
 			entry: &ServiceResolverConfigEntry{
@@ -83,6 +96,17 @@ func TestServiceResolverConfigEntry_OSS(t *testing.T) {
 			},
 			validateErr: `Bad Failover["*"]: Setting failover policies requires Consul Enterprise`,
 		},
+		{
+			name: "setting redirect SamenessGroup on OSS",
+			entry: &ServiceResolverConfigEntry{
+				Kind: ServiceResolver,
+				Name: "test",
+				Redirect: &ServiceResolverRedirect{
+					SamenessGroup: "group",
+				},
+			},
+			validateErr: `Redirect: Setting SamenessGroup requires Consul Enterprise`,
+		},
 		{
 			name: "setting redirect Namespace on OSS",
 			entry: &ServiceResolverConfigEntry{

api/config_entry_discoverychain.go

@@ -234,6 +234,7 @@ type ServiceResolverRedirect struct {
 	Partition     string `json:",omitempty"`
 	Datacenter    string `json:",omitempty"`
 	Peer          string `json:",omitempty"`
+	SamenessGroup string `json:",omitempty"`
 }
 
 type ServiceResolverFailover struct {
@@ -244,6 +245,7 @@ type ServiceResolverFailover struct {
 	Datacenters   []string                        `json:",omitempty"`
 	Targets       []ServiceResolverFailoverTarget `json:",omitempty"`
 	Policy        *ServiceResolverFailoverPolicy  `json:",omitempty"`
+	SamenessGroup string                          `json:",omitempty"`
 }
 
 type ServiceResolverFailoverTarget struct {

proto/private/pbconfigentry/config_entry.gen.go

@@ -1415,6 +1415,7 @@ func ServiceResolverFailoverToStructs(s *ServiceResolverFailover, t *structs.Ser
 		ServiceResolverFailoverPolicyToStructs(s.Policy, &x)
 		t.Policy = &x
 	}
+	t.SamenessGroup = s.SamenessGroup
 }
 func ServiceResolverFailoverFromStructs(t *structs.ServiceResolverFailover, s *ServiceResolverFailover) {
 	if s == nil {
@@ -1439,6 +1440,7 @@ func ServiceResolverFailoverFromStructs(t *structs.ServiceResolverFailover, s *S
 		ServiceResolverFailoverPolicyFromStructs(t.Policy, &x)
 		s.Policy = &x
 	}
+	s.SamenessGroup = t.SamenessGroup
 }
 func ServiceResolverFailoverPolicyToStructs(s *ServiceResolverFailoverPolicy, t *structs.ServiceResolverFailoverPolicy) {
 	if s == nil {
@@ -1484,6 +1486,7 @@ func ServiceResolverRedirectToStructs(s *ServiceResolverRedirect, t *structs.Ser
 	t.Partition = s.Partition
 	t.Datacenter = s.Datacenter
 	t.Peer = s.Peer
+	t.SamenessGroup = s.SamenessGroup
 }
 func ServiceResolverRedirectFromStructs(t *structs.ServiceResolverRedirect, s *ServiceResolverRedirect) {
 	if s == nil {
@@ -1495,6 +1498,7 @@ func ServiceResolverRedirectFromStructs(t *structs.ServiceResolverRedirect, s *S
 	s.Partition = t.Partition
 	s.Datacenter = t.Datacenter
 	s.Peer = t.Peer
+	s.SamenessGroup = t.SamenessGroup
 }
 func ServiceResolverSubsetToStructs(s *ServiceResolverSubset, t *structs.ServiceResolverSubset) {
 	if s == nil {

proto/private/pbconfigentry/config_entry.proto

@@ -147,6 +147,7 @@ message ServiceResolverRedirect {
   string Partition = 4;
   string Datacenter = 5;
   string Peer = 6;
+  string SamenessGroup = 7;
 }
 
 // mog annotation:
@@ -161,6 +162,7 @@ message ServiceResolverFailover {
   repeated string Datacenters = 4;
   repeated ServiceResolverFailoverTarget Targets = 5;
   ServiceResolverFailoverPolicy Policy = 6;
+  string SamenessGroup = 7;
 }
 
 // mog annotation: