state: convert config-entries table to new indexer pattern

Using functional indexes to isolate enterprise differentiation and
remove reflection.

agent/consul/state/config_entry.go

@@ -106,7 +106,7 @@ func configEntryTxn(tx ReadTxn, ws memdb.WatchSet, kind, name string, entMeta *s
 	idx := maxIndexTxn(tx, tableConfigEntries)
 
 	// Get the existing config entry.
-	watchCh, existing, err := firstWatchConfigEntryWithTxn(tx, kind, name, entMeta)
+	watchCh, existing, err := tx.FirstWatch(tableConfigEntries, "id", NewConfigEntryKindName(kind, name, entMeta))
 	if err != nil {
 		return 0, nil, fmt.Errorf("failed config entry lookup: %s", err)
 	}
@@ -175,7 +175,7 @@ func (s *Store) EnsureConfigEntry(idx uint64, conf structs.ConfigEntry) error {
 // ensureConfigEntryTxn upserts a config entry inside of a transaction.
 func ensureConfigEntryTxn(tx WriteTxn, idx uint64, conf structs.ConfigEntry) error {
 	// Check for existing configuration.
-	existing, err := firstConfigEntryWithTxn(tx, conf.GetKind(), conf.GetName(), conf.GetEnterpriseMeta())
+	existing, err := tx.First(tableConfigEntries, indexID, newConfigEntryQuery(conf))
 	if err != nil {
 		return fmt.Errorf("failed configuration lookup: %s", err)
 	}
@@ -214,7 +214,7 @@ func (s *Store) EnsureConfigEntryCAS(idx, cidx uint64, conf structs.ConfigEntry)
 	defer tx.Abort()
 
 	// Check for existing configuration.
-	existing, err := firstConfigEntryWithTxn(tx, conf.GetKind(), conf.GetName(), conf.GetEnterpriseMeta())
+	existing, err := tx.First(tableConfigEntries, indexID, newConfigEntryQuery(conf))
 	if err != nil {
 		return false, fmt.Errorf("failed configuration lookup: %s", err)
 	}
@@ -254,9 +254,9 @@ func (s *Store) DeleteConfigEntry(idx uint64, kind, name string, entMeta *struct
 	return tx.Commit()
 }
 
+// TODO: accept structs.ConfigEntry instead of individual fields
 func deleteConfigEntryTxn(tx WriteTxn, idx uint64, kind, name string, entMeta *structs.EnterpriseMeta) error {
-	// Try to retrieve the existing config entry.
-	existing, err := firstConfigEntryWithTxn(tx, kind, name, entMeta)
+	existing, err := tx.First(tableConfigEntries, indexID, NewConfigEntryKindName(kind, name, entMeta))
 	if err != nil {
 		return fmt.Errorf("failed config entry lookup: %s", err)
 	}
@@ -1242,3 +1242,7 @@ func NewConfigEntryKindName(kind, name string, entMeta *structs.EnterpriseMeta)
 	ret.EnterpriseMeta.Normalize()
 	return ret
 }
+
+func newConfigEntryQuery(c structs.ConfigEntry) ConfigEntryKindName {
+	return NewConfigEntryKindName(c.GetKind(), c.GetName(), c.GetEnterpriseMeta())
+}

agent/consul/state/config_entry_oss.go

@@ -3,22 +3,40 @@
 package state
 
 import (
+	"fmt"
+	"strings"
+
 	memdb "github.com/hashicorp/go-memdb"
 
 	"github.com/hashicorp/consul/agent/structs"
 )
 
-func firstConfigEntryWithTxn(tx ReadTxn, kind, name string, _ *structs.EnterpriseMeta) (interface{}, error) {
-	return tx.First(tableConfigEntries, "id", kind, name)
+func indexFromConfigEntryKindName(arg interface{}) ([]byte, error) {
+	n, ok := arg.(ConfigEntryKindName)
+	if !ok {
+		return nil, fmt.Errorf("invalid type for ConfigEntryKindName query: %T", arg)
+	}
+
+	var b indexBuilder
+	b.String(strings.ToLower(n.Kind))
+	b.String(strings.ToLower(n.Name))
+	return b.Bytes(), nil
 }
 
-func firstWatchConfigEntryWithTxn(
-	tx ReadTxn,
-	kind string,
-	name string,
-	_ *structs.EnterpriseMeta,
-) (<-chan struct{}, interface{}, error) {
-	return tx.FirstWatch(tableConfigEntries, "id", kind, name)
+func indexFromConfigEntry(raw interface{}) ([]byte, error) {
+	c, ok := raw.(structs.ConfigEntry)
+	if !ok {
+		return nil, fmt.Errorf("type must be structs.ConfigEntry: %T", raw)
+	}
+
+	if c.GetName() == "" || c.GetKind() == "" {
+		return nil, errMissingValueForIndex
+	}
+
+	var b indexBuilder
+	b.String(strings.ToLower(c.GetKind()))
+	b.String(strings.ToLower(c.GetName()))
+	return b.Bytes(), nil
 }
 
 func validateConfigEntryEnterprise(_ ReadTxn, _ structs.ConfigEntry) error {

agent/consul/state/config_entry_schema.go

@@ -1,6 +1,8 @@
 package state
 
-import "github.com/hashicorp/go-memdb"
+import (
+	"github.com/hashicorp/go-memdb"
+)
 
 const (
 	tableConfigEntries = "config-entries"
@@ -20,17 +22,9 @@ func configTableSchema() *memdb.TableSchema {
 				Name:         indexID,
 				AllowMissing: false,
 				Unique:       true,
-				Indexer: &memdb.CompoundIndex{
-					Indexes: []memdb.Indexer{
-						&memdb.StringFieldIndex{
-							Field:     "Kind",
-							Lowercase: true,
-						},
-						&memdb.StringFieldIndex{
-							Field:     "Name",
-							Lowercase: true,
-						},
-					},
+				Indexer: indexerSingle{
+					readIndex:  readIndex(indexFromConfigEntryKindName),
+					writeIndex: writeIndex(indexFromConfigEntry),
 				},
 			},
 			indexKind: {

agent/consul/state/testdata/TestStateStoreSchema.golden

@@ -60,7 +60,7 @@ table=checks
 
 table=config-entries
   index=id unique
-    indexer=github.com/hashicorp/go-memdb.CompoundIndex Indexes=[github.com/hashicorp/go-memdb.StringFieldIndex Field=Kind Lowercase=true, github.com/hashicorp/go-memdb.StringFieldIndex Field=Name Lowercase=true] AllowMissing=false
+    indexer=github.com/hashicorp/consul/agent/consul/state.indexerSingle readIndex=github.com/hashicorp/consul/agent/consul/state.indexFromConfigEntryKindName writeIndex=github.com/hashicorp/consul/agent/consul/state.indexFromConfigEntry
   index=intention-legacy-id unique allow-missing
     indexer=github.com/hashicorp/consul/agent/consul/state.ServiceIntentionLegacyIDIndex uuidFieldIndex={}
   index=intention-source allow-missing