feat: add OnConflict=DoNothing on create operations

adapter.go

@@ -31,6 +31,7 @@ import (
 	"gorm.io/driver/postgres"
 	"gorm.io/driver/sqlserver"
 	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
 	"gorm.io/gorm/logger"
 	"gorm.io/plugin/dbresolver"
 )
@@ -626,7 +627,7 @@ func (a *Adapter) SavePolicyCtx(ctx context.Context, model model.Model) error {
 		for _, rule := range ast.Policy {
 			lines = append(lines, a.savePolicyLine(ptype, rule))
 			if len(lines) > flushEvery {
-				if err := tx.Create(&lines).Error; err != nil {
+				if err := tx.Clauses(clause.OnConflict{DoNothing: true}).Create(&lines).Error; err != nil {
 					tx.Rollback()
 					return err
 				}
@@ -639,7 +640,7 @@ func (a *Adapter) SavePolicyCtx(ctx context.Context, model model.Model) error {
 		for _, rule := range ast.Policy {
 			lines = append(lines, a.savePolicyLine(ptype, rule))
 			if len(lines) > flushEvery {
-				if err := tx.Create(&lines).Error; err != nil {
+				if err := tx.Clauses(clause.OnConflict{DoNothing: true}).Create(&lines).Error; err != nil {
 					tx.Rollback()
 					return err
 				}
@@ -648,7 +649,7 @@ func (a *Adapter) SavePolicyCtx(ctx context.Context, model model.Model) error {
 		}
 	}
 	if len(lines) > 0 {
-		if err := tx.Create(&lines).Error; err != nil {
+		if err := tx.Clauses(clause.OnConflict{DoNothing: true}).Create(&lines).Error; err != nil {
 			tx.Rollback()
 			return err
 		}
@@ -666,7 +667,7 @@ func (a *Adapter) AddPolicy(sec string, ptype string, rule []string) error {
 // AddPolicyCtx adds a policy rule to the storage.
 func (a *Adapter) AddPolicyCtx(ctx context.Context, sec string, ptype string, rule []string) error {
 	line := a.savePolicyLine(ptype, rule)
-	err := a.db.WithContext(ctx).Create(&line).Error
+	err := a.db.WithContext(ctx).Clauses(clause.OnConflict{DoNothing: true}).Create(&line).Error
 	return err
 }
 
@@ -689,7 +690,7 @@ func (a *Adapter) AddPolicies(sec string, ptype string, rules [][]string) error
 		line := a.savePolicyLine(ptype, rule)
 		lines = append(lines, line)
 	}
-	return a.db.Create(&lines).Error
+	return a.db.Clauses(clause.OnConflict{DoNothing: true}).Create(&lines).Error
 }
 
 // Transaction perform a set of operations within a transaction
@@ -930,7 +931,7 @@ func (a *Adapter) UpdateFilteredPolicies(sec string, ptype string, newPolicies [
 		return nil, err
 	}
 	for i := range newP {
-		if err := tx.Create(&newP[i]).Error; err != nil {
+		if err := tx.Clauses(clause.OnConflict{DoNothing: true}).Create(&newP[i]).Error; err != nil {
 			tx.Rollback()
 			return nil, err
 		}

adapter_test.go

@@ -681,6 +681,46 @@ func TestAddPolicies(t *testing.T) {
 	testGetPolicy(t, e, [][]string{{"alice", "data1", "read"}, {"bob", "data2", "write"}, {"data2_admin", "data2", "read"}, {"data2_admin", "data2", "write"}, {"jack", "data1", "read"}, {"jack2", "data1", "read"}})
 }
 
+func TestAddPolicy(t *testing.T) {
+	tests := []struct {
+		driverName     string
+		dataSourceName string
+		params         []any
+	}{
+		{"mysql", "root:@tcp(127.0.0.1:3306)/", []any{"casbin", "casbin_rule"}},
+		{"postgres", "user=postgres password=postgres host=127.0.0.1 port=5432 sslmode=disable", nil},
+		// {"sqlserver", "sqlserver://sa:SqlServer123@localhost:1433", []any{"master", "casbin_rule"}},
+	}
+
+	for _, test := range tests {
+		test := test
+		t.Run(test.driverName, func(t *testing.T) {
+			t.Parallel()
+			a := initAdapter(t, test.driverName, test.dataSourceName, test.params...)
+			e1, _ := casbin.NewEnforcer("examples/rbac_model.conf", a)
+			e2, _ := casbin.NewEnforcer("examples/rbac_model.conf", a)
+
+			policy := []string{"alice", "data1", "TestAddPolicy"}
+
+			ok, err := e1.AddPolicy(policy)
+			if err != nil {
+				t.Errorf("e1.AddPolicy() got err %v", err)
+			}
+			if !ok {
+				t.Errorf("e1.AddPolicy() got false, want true")
+			}
+
+			ok, err = e2.AddPolicy(policy)
+			if err != nil {
+				t.Errorf("e2.AddPolicy() got err %v", err)
+			}
+			if !ok {
+				t.Errorf("e2.AddPolicy() got false, want true")
+			}
+		})
+	}
+}
+
 func TestTransaction(t *testing.T) {
 	a := initAdapter(t, "mysql", "root:@tcp(127.0.0.1:3306)/", "casbin", "casbin_rule")
 	e, _ := casbin.NewEnforcer("examples/rbac_model.conf", a)