consul/state: starting on new state store

consul/state/schema.go

@@ -0,0 +1,54 @@
+package state
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/go-memdb"
+)
+
+// schemaFn is an interface function used to create and return
+// new memdb schema structs for constructing an in-memory db.
+type schemaFn func() *memdb.TableSchema
+
+// stateStoreSchema is used to return the combined schema for
+// the state store.
+func stateStoreSchema() *memdb.DBSchema {
+	// Create the root DB schema
+	db := &memdb.DBSchema{
+		Tables: make(map[string]*memdb.TableSchema),
+	}
+
+	// Collect the needed schemas
+	schemas := []schemaFn{
+		indexTableSchema,
+	}
+
+	// Add the tables to the root schema
+	for _, fn := range schemas {
+		schema := fn()
+		if _, ok := db.Tables[schema.Name]; ok {
+			panic(fmt.Sprintf("duplicate table name: %s", schema.Name))
+		}
+		db.Tables[schema.Name] = schema
+	}
+	return db
+}
+
+// indexTableSchema returns a new table schema used for
+// tracking various indexes for the Raft log.
+func indexTableSchema() *memdb.TableSchema {
+	return &memdb.TableSchema{
+		Name: "index",
+		Indexes: map[string]*memdb.IndexSchema{
+			"id": &memdb.IndexSchema{
+				Name:         "id",
+				AllowMissing: false,
+				Unique:       true,
+				Indexer: &memdb.StringFieldIndex{
+					Field:     "Key",
+					Lowercase: true,
+				},
+			},
+		},
+	}
+}

consul/state/state_store.go

@@ -0,0 +1,34 @@
+package state
+
+import (
+	"fmt"
+	"io"
+	"log"
+
+	"github.com/hashicorp/go-memdb"
+)
+
+type StateStore struct {
+	logger *log.Logger
+	db     *memdb.MemDB
+}
+
+type IndexEntry struct {
+	Key   string
+	Value uint64
+}
+
+func NewStateStore(logOutput io.Writer) (*StateStore, error) {
+	// Create the in-memory DB
+	db, err := memdb.NewMemDB(stateStoreSchema())
+	if err != nil {
+		return nil, fmt.Errorf("Failed setting up state store: %s", err)
+	}
+
+	// Create and return the state store
+	s := &StateStore{
+		logger: log.New(logOutput, "", log.LstdFlags),
+		db:     db,
+	}
+	return s, nil
+}