Split primary_key gen as single file

primary_key.go

@@ -0,0 +1,29 @@
+package sharding
+
+import "fmt"
+
+const (
+	// Use Snowflake primary key generator
+	PKSnowflake = iota
+	// Use PostgreSQL sequence primary key generator
+	PKPGSequence
+	// Use custom primary key generator
+	PKCustom
+)
+
+func (s *Sharding) genSnowflakeKey(index int64) int64 {
+	return s.snowflakeNodes[index].Generate().Int64()
+}
+
+func (s *Sharding) genPostgreSQLSequenceKey(tableName string, index int64) int64 {
+	var id int64
+	err := s.DB.Raw("SELECT nextval('" + pgSeqName(tableName) + "')").Scan(&id).Error
+	if err != nil {
+		panic(err)
+	}
+	return id
+}
+
+func pgSeqName(table string) string {
+	return fmt.Sprintf("gorm_sharding_%s_id_seq", table)
+}

primary_key_test.go

@@ -0,0 +1,11 @@
+package sharding
+
+import (
+	"testing"
+
+	"github.com/longbridgeapp/assert"
+)
+
+func Test_pgSeqName(t *testing.T) {
+	assert.Equal(t, "gorm_sharding_users_id_seq", pgSeqName("users"))
+}

sharding.go

@@ -14,12 +14,6 @@ import (
 	"gorm.io/gorm/schema"
 )
 
-const (
-	PKSnowflake  = iota // Use Snowflake primary key generator
-	PKPGSequence        // Use PostgreSQL sequence primary key generator
-	PKCustom            // Use custom primary key generator
-)
-
 var (
 	ErrMissingShardingKey = errors.New("sharding key or id required, and use operator =")
 	ErrInvalidID          = errors.New("invalid id format")
@@ -109,17 +103,10 @@ func (s *Sharding) Register(config Config, tables ...interface{}) *Sharding {
 		}
 
 		if c.PrimaryKeyGenerator == PKSnowflake {
-			c.PrimaryKeyGeneratorFn = func(index int64) int64 {
-				return s.snowflakeNodes[index].Generate().Int64()
-			}
+			c.PrimaryKeyGeneratorFn = s.genSnowflakeKey
 		} else if c.PrimaryKeyGenerator == PKPGSequence {
 			c.PrimaryKeyGeneratorFn = func(index int64) int64 {
-				var id int64
-				err := s.DB.Raw("SELECT nextval('" + pgSeqName(t) + "')").Scan(&id).Error
-				if err != nil {
-					panic(err)
-				}
-				return id
+				return s.genPostgreSQLSequenceKey(t, index)
 			}
 		} else if c.PrimaryKeyGenerator == PKCustom {
 			if c.PrimaryKeyGeneratorFn == nil {
@@ -435,7 +422,3 @@ func replaceOrderByTableName(orderBy []*sqlparser.OrderingTerm, oldName, newName
 
 	return orderBy
 }
-
-func pgSeqName(table string) string {
-	return fmt.Sprintf("gorm_sharding_%s_id_seq", table)
-}