Parameterize genString by length

http/server.go

@@ -220,11 +220,10 @@ const keyAdminCode = "admin_code"
 
 var chars = []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
 
-func genString() (string, error) {
-	const length = 10
+func genString(length int) (string, error) {
 	charsLength := big.NewInt(int64(len(chars)))
 	var maxN big.Int
-	maxN.Exp(charsLength, big.NewInt(length), nil)
+	maxN.Exp(charsLength, big.NewInt(int64(length)), nil)
 	n, err := rand.Int(rand.Reader, &maxN)
 	if err != nil {
 		return "", err

store.go

@@ -11,7 +11,7 @@ import (
 	"crawshaw.io/sqlite/sqlitex"
 )
 
-type GenString func() (string, error)
+type GenString func(length int) (string, error)
 
 type Store struct {
 	pool      *sqlitex.Pool
@@ -102,15 +102,18 @@ type CreateEventResult struct {
 const dbDateLayout = "2006-01-02"
 
 func (s *Store) CreateEvent(ctx context.Context, cmd CreateEventCommand) (result CreateEventResult, err error) {
+	const alphaIDLength = 10
+	const adminCodeLength = 10
+
 	conn := s.pool.Get(ctx)
 	defer s.pool.Put(conn)
 
-	alphaID, err := s.genString()
+	alphaID, err := s.genString(alphaIDLength)
 	if err != nil {
 		return
 	}
 
-	adminCode, err := s.genString()
+	adminCode, err := s.genString(adminCodeLength)
 	if err != nil {
 		return
 	}