If your gorm.io/driver/postgres version is v1.4.6 (pgx version is github.com/jackc/pgx/v5), gorm model field is mapped to proto enum, will be failed, You need an explicit gen Scan & Value method.

https://github.com/go-gorm/postgres/blob/v1.4.5/go.mod -> github.com/jackc/pgx/v4 v4.17.2

https://github.com/go-gorm/postgres/blob/v1.4.6/go.mod -> github.com/jackc/pgx/v5 v5.2.0

---

protoc-gen-gorm-serializer

Install

go install github.com/yangyang5214/protoc-gen-gorm-serializer@latest

Usage

Add --go_out as a parameter to protoc, for example:

• task.proto

syntax = "proto3";

enum TaskStatus {
  Unknown = 0;
  Running = 1;
  Exiting = 2;
  Pending = 3;
}

option go_package = "github.com/yangyang5214/protoc-gen-gorm-serializer/example";

• run protoc cmd

protoc --proto_path=.  --go_out=paths=source_relative:. --gorm-serializer_out=paths=source_relative:.  task.proto

• gen task_gorm_serializer.pb.go file

// Code generated by protoc-gen-gorm_serializer. DO NOT EDIT.
// versions:
// - protoc             v3.21.12
// source: task.proto

package example

import "database/sql/driver"

func (x *TaskStatus) Scan(v any) (err error) {
	*x = TaskStatus(v.(int64))
	return nil
}

func (x TaskStatus) Value() (v driver.Value, err error) {
	return int32(x), nil
}

• use gorm field

type Task struct {
	gorm.Model
	Name   string
	Status example.TaskStatus `gorm:"type:int"`
}

func (Task) TableName() string {
	return "task"
}

func main() {
	db, err := gorm.Open(sqlite.Open("/tmp/test.db"), &gorm.Config{})
	if err != nil {
		panic("failed to connect database")
	}

	err = db.AutoMigrate(&Task{})
	if err != nil {
		panic(err)
	}

	t := &Task{
		Name:   "task_name_test",
		Status: example.TaskStatus_Exiting,
	}

	// Create
	tx := db.Create(t)
	if tx.Error != nil {
		panic(tx.Error)
	}

	// Read
	var task Task
	db.Where(Task{Name: "task_name_test"})
	db.First(&task)

	fmt.Println(fmt.Sprintf("task status is: %s", task.Status))
}

Example

https://github.com/yangyang5214/protoc-gen-gorm-serializer-example

References

https://github.com/go-kratos/kratos/tree/main/cmd/protoc-gen-go-http

https://gorm.io/docs/data_types.html