fix(kv): add legacy variable orgs index back

issue here is that the unique by name index for variables was implemented
and has the same functionality about it that this orgs index has. The duplicative
orgs index was nuked. The migration to hydrate the org/name index never
happened. This is a stop gap until that migration is in place.

kv/service.go

@@ -147,6 +147,10 @@ func (s *Service) Initialize(ctx context.Context) error {
 			return err
 		}
 
+		if err := s.initializeVariablesOrgIndex(tx); err != nil {
+			return err
+		}
+
 		if err := s.initializeChecks(ctx, tx); err != nil {
 			return err
 		}

kv/variable.go

@@ -1,6 +1,7 @@
 package kv
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -9,6 +10,78 @@ import (
 	"github.com/influxdata/influxdb"
 )
 
+// TODO: eradicate this with migration strategy
+var variableOrgsIndex = []byte("variableorgsv1")
+
+func (s *Service) initializeVariablesOrgIndex(tx Tx) error {
+	if _, err := tx.Bucket(variableOrgsIndex); err != nil {
+		return err
+	}
+	return nil
+}
+
+func decodeVariableOrgsIndexKey(indexKey []byte) (orgID influxdb.ID, variableID influxdb.ID, err error) {
+	if len(indexKey) != 2*influxdb.IDLength {
+		return 0, 0, &influxdb.Error{
+			Code: influxdb.EInvalid,
+			Msg:  "malformed variable orgs index key (please report this error)",
+		}
+	}
+
+	if err := (&orgID).Decode(indexKey[:influxdb.IDLength]); err != nil {
+		return 0, 0, &influxdb.Error{
+			Code: influxdb.EInvalid,
+			Msg:  "bad org id",
+			Err:  influxdb.ErrInvalidID,
+		}
+	}
+
+	if err := (&variableID).Decode(indexKey[influxdb.IDLength:]); err != nil {
+		return 0, 0, &influxdb.Error{
+			Code: influxdb.EInvalid,
+			Msg:  "bad variable id",
+			Err:  influxdb.ErrInvalidID,
+		}
+	}
+
+	return orgID, variableID, nil
+}
+
+func (s *Service) findOrganizationVariables(ctx context.Context, tx Tx, orgID influxdb.ID) ([]*influxdb.Variable, error) {
+	idx, err := tx.Bucket(variableOrgsIndex)
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO(leodido): support find options
+	cur, err := idx.Cursor()
+	if err != nil {
+		return nil, err
+	}
+
+	prefix, err := orgID.Encode()
+	if err != nil {
+		return nil, err
+	}
+
+	variables := []*influxdb.Variable{}
+	for k, _ := cur.Seek(prefix); bytes.HasPrefix(k, prefix); k, _ = cur.Next() {
+		_, id, err := decodeVariableOrgsIndexKey(k)
+		if err != nil {
+			return nil, err
+		}
+
+		m, err := s.findVariableByID(ctx, tx, id)
+		if err != nil {
+			return nil, err
+		}
+
+		variables = append(variables, m)
+	}
+
+	return variables, nil
+}
+
 func newVariableUniqueByNameStore() *IndexStore {
 	const resource = "variable"
 
@@ -37,31 +110,6 @@ func newVariableUniqueByNameStore() *IndexStore {
 	}
 }
 
-func (s *Service) findOrganizationVariables(ctx context.Context, tx Tx, orgID influxdb.ID) ([]*influxdb.Variable, error) {
-	prefix, err := orgID.Encode()
-	if err != nil {
-		return nil, err
-	}
-
-	variables := []*influxdb.Variable{}
-	err = s.variableStore.Find(ctx, tx, FindOpts{
-		Prefix: prefix,
-		CaptureFn: func(key []byte, decodedVal interface{}) error {
-			v, ok := decodedVal.(*influxdb.Variable)
-			if err := errUnexpectedDecodeVal(ok); err != nil {
-				return err
-			}
-			variables = append(variables, v)
-			return nil
-		},
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	return variables, nil
-}
-
 func (s *Service) findVariables(ctx context.Context, tx Tx, filter influxdb.VariableFilter) ([]*influxdb.Variable, error) {
 	if filter.OrganizationID != nil {
 		return s.findOrganizationVariables(ctx, tx, *filter.OrganizationID)
@@ -176,6 +224,7 @@ func (s *Service) CreateVariable(ctx context.Context, v *influxdb.Variable) erro
 		now := s.Now()
 		v.CreatedAt = now
 		v.UpdatedAt = now
+
 		return s.putVariable(ctx, tx, v)
 	})
 }
@@ -200,6 +249,10 @@ func (s *Service) ReplaceVariable(ctx context.Context, v *influxdb.Variable) err
 }
 
 func (s *Service) putVariable(ctx context.Context, tx Tx, v *influxdb.Variable) error {
+	if err := s.putVariableOrgsIndex(tx, v); err != nil {
+		return err
+	}
+
 	ent := Entity{
 		ID:    v.ID,
 		Name:  v.Name,
@@ -263,6 +316,74 @@ func (s *Service) UpdateVariable(ctx context.Context, id influxdb.ID, update *in
 // DeleteVariable removes a single variable from the store by its ID
 func (s *Service) DeleteVariable(ctx context.Context, id influxdb.ID) error {
 	return s.kv.Update(ctx, func(tx Tx) error {
+		v, err := s.findVariableByID(ctx, tx, id)
+		if err != nil {
+			return err
+		}
+
+		if err := s.removeVariableOrgsIndex(tx, v); err != nil {
+			return err
+		}
 		return s.variableStore.DeleteEnt(ctx, tx, Entity{ID: id})
 	})
 }
+
+func encodeVariableOrgsIndex(variable *influxdb.Variable) ([]byte, error) {
+	oID, err := variable.OrganizationID.Encode()
+	if err != nil {
+		return nil, &influxdb.Error{
+			Err: err,
+			Msg: "bad organization id",
+		}
+	}
+
+	mID, err := variable.ID.Encode()
+	if err != nil {
+		return nil, &influxdb.Error{
+			Err: err,
+			Msg: "bad variable id",
+		}
+	}
+
+	key := make([]byte, 0, influxdb.IDLength*2)
+	key = append(key, oID...)
+	key = append(key, mID...)
+
+	return key, nil
+}
+
+func (s *Service) putVariableOrgsIndex(tx Tx, variable *influxdb.Variable) error {
+	key, err := encodeVariableOrgsIndex(variable)
+	if err != nil {
+		return err
+	}
+
+	idx, err := tx.Bucket(variableOrgsIndex)
+	if err != nil {
+		return &influxdb.Error{Code: influxdb.EInternal, Err: err}
+	}
+
+	if err := idx.Put(key, nil); err != nil {
+		return &influxdb.Error{Code: influxdb.EInternal, Err: err}
+	}
+
+	return nil
+}
+
+func (s *Service) removeVariableOrgsIndex(tx Tx, variable *influxdb.Variable) error {
+	key, err := encodeVariableOrgsIndex(variable)
+	if err != nil {
+		return err
+	}
+
+	idx, err := tx.Bucket(variableOrgsIndex)
+	if err != nil {
+		return &influxdb.Error{Code: influxdb.EInternal, Err: err}
+	}
+
+	if err := idx.Delete(key); err != nil {
+		return &influxdb.Error{Code: influxdb.EInternal, Err: err}
+	}
+
+	return nil
+}