go-zero model命令

model命令

goctl model 为go-zero下的工具模块中的组件之一，目前支持识别mysql ddl进行model层代码生成，通过命令行或者idea插件（即将支持）可以有选择地生成带redis cache或者不带redis cache的代码逻辑。

快速开始

• 通过ddl生成

  $ goctl model mysql ddl -src="./*.sql" -dir="./sql/model" -c

• 执行上述命令后即可快速生成CURD代码。

  model
  ├── usermodel.go
  ├── usermodel_gen.go
  └── vars.go

• 通过datasource生成

  $ goctl model mysql datasource -url="user:password@tcp(127.0.0.1:3306)/database" -table="*"  -dir="./model"

• usermodel_gen.go

// Code generated by goctl. DO NOT EDIT!

package model

import (
    "context"
    "database/sql"
    "fmt"
    "strings"
    "time"

    "github.com/zeromicro/go-zero/core/stores/builder"
    "github.com/zeromicro/go-zero/core/stores/cache"
    "github.com/zeromicro/go-zero/core/stores/sqlc"
    "github.com/zeromicro/go-zero/core/stores/sqlx"
    "github.com/zeromicro/go-zero/core/stringx"
)

var (
    userFieldNames          = builder.RawFieldNames(&User{})
    userRows                = strings.Join(userFieldNames, ",")
    userRowsExpectAutoSet   = strings.Join(stringx.Remove(userFieldNames, "`id`", "`create_time`", "`update_time`"), ",")
    userRowsWithPlaceHolder = strings.Join(stringx.Remove(userFieldNames, "`id`", "`create_time`", "`update_time`"), "=?,") + "=?"

    cacheUserIdPrefix     = "cache:user:id:"
    cacheUserNumberPrefix = "cache:user:number:"
)

type (
    userModel interface {
        Insert(ctx context.Context, data *User) (sql.Result, error)
        FindOne(ctx context.Context, id int64) (*User, error)
        FindOneByNumber(ctx context.Context, number string) (*User, error)
        Update(ctx context.Context, data *User) error
        Delete(ctx context.Context, id int64) error
    }

    defaultUserModel struct {
        sqlc.CachedConn
        table string
    }

    User struct {
        Id         int64     `db:"id"`
        Number     string    `db:"number"`   // 学号
        Name       string    `db:"name"`     // 用户名称
        Password   string    `db:"password"` // 用户密码
        Gender     string    `db:"gender"`   // 男｜女｜未公开
        CreateTime time.Time `db:"create_time"`
        UpdateTime time.Time `db:"update_time"`
    }
)

func newUserModel(conn sqlx.SqlConn, c cache.CacheConf) *defaultUserModel {
    return &defaultUserModel{
        CachedConn: sqlc.NewConn(conn, c),
        table:      "`user`",
    }
}

func (m *defaultUserModel) Insert(ctx context.Context, data *User) (sql.Result, error) {
    userIdKey := fmt.Sprintf("%s%v", cacheUserIdPrefix, data.Id)
    userNumberKey := fmt.Sprintf("%s%v", cacheUserNumberPrefix, data.Number)
    ret, err := m.ExecCtx(ctx, func(ctx context.Context, conn sqlx.SqlConn) (result sql.Result, err error) {
        query := fmt.Sprintf("insert into %s (%s) values (?, ?, ?, ?)", m.table, userRowsExpectAutoSet)
        return conn.ExecCtx(ctx, query, data.Number, data.Name, data.Password, data.Gender)
    }, userIdKey, userNumberKey)
    return ret, err
}

func (m *defaultUserModel) FindOne(ctx context.Context, id int64) (*User, error) {
    userIdKey := fmt.Sprintf("%s%v", cacheUserIdPrefix, id)
    var resp User
    err := m.QueryRowCtx(ctx, &resp, userIdKey, func(ctx context.Context, conn sqlx.SqlConn, v interface{}) error {
        query := fmt.Sprintf("select %s from %s where `id` = ? limit 1", userRows, m.table)
        return conn.QueryRowCtx(ctx, v, query, id)
    })
    switch err {
    case nil:
        return &resp, nil
    case sqlc.ErrNotFound:
        return nil, ErrNotFound
    default:
        return nil, err
    }
}

func (m *defaultUserModel) FindOneByNumber(ctx context.Context, number string) (*User, error) {
    userNumberKey := fmt.Sprintf("%s%v", cacheUserNumberPrefix, number)
    var resp User
    err := m.QueryRowIndexCtx(ctx, &resp, userNumberKey, m.formatPrimary, func(ctx context.Context, conn sqlx.SqlConn, v interface{}) (i interface{}, e error) {
        query := fmt.Sprintf("select %s from %s where `number` = ? limit 1", userRows, m.table)
        if err := conn.QueryRowCtx(ctx, &resp, query, number); err != nil {
            return nil, err
        }
        return resp.Id, nil
    }, m.queryPrimary)
    switch err {
    case nil:
        return &resp, nil
    case sqlc.ErrNotFound:
        return nil, ErrNotFound
    default:
        return nil, err
    }
}

func (m *defaultUserModel) Update(ctx context.Context, data *User) error {
    userIdKey := fmt.Sprintf("%s%v", cacheUserIdPrefix, data.Id)
    userNumberKey := fmt.Sprintf("%s%v", cacheUserNumberPrefix, data.Number)
    _, err := m.ExecCtx(ctx, func(ctx context.Context, conn sqlx.SqlConn) (result sql.Result, err error) {
        query := fmt.Sprintf("update %s set %s where `id` = ?", m.table, userRowsWithPlaceHolder)
        return conn.ExecCtx(ctx, query, data.Number, data.Name, data.Password, data.Gender, data.Id)
    }, userIdKey, userNumberKey)
    return err
}

func (m *defaultUserModel) Delete(ctx context.Context, id int64) error {
    data, err := m.FindOne(ctx, id)
    if err != nil {
        return err
    }

    userIdKey := fmt.Sprintf("%s%v", cacheUserIdPrefix, id)
    userNumberKey := fmt.Sprintf("%s%v", cacheUserNumberPrefix, data.Number)
    _, err = m.ExecCtx(ctx, func(ctx context.Context, conn sqlx.SqlConn) (result sql.Result, err error) {
        query := fmt.Sprintf("delete from %s where `id` = ?", m.table)
        return conn.ExecCtx(ctx, query, id)
    }, userIdKey, userNumberKey)
    return err
}

func (m *defaultUserModel) formatPrimary(primary interface{}) string {
    return fmt.Sprintf("%s%v", cacheUserIdPrefix, primary)
}

func (m *defaultUserModel) queryPrimary(ctx context.Context, conn sqlx.SqlConn, v, primary interface{}) error {
    query := fmt.Sprintf("select %s from %s where `id` = ? limit 1", userRows, m.table)
    return conn.QueryRowCtx(ctx, v, query, primary)
}

func (m *defaultUserModel) tableName() string {
    return m.table
}

• usermodel.go

package model

import (
    "github.com/zeromicro/go-zero/core/stores/cache"
    "github.com/zeromicro/go-zero/core/stores/sqlx"
)

var _ UserModel = (*customUserModel)(nil)

type (
    // UserModel is an interface to be customized, add more methods here,
    // and implement the added methods in customUserModel.
    UserModel interface {
        userModel
    }

    customUserModel struct {
        *defaultUserModel
    }
)

// NewUserModel returns a model for the database table.
func NewUserModel(conn sqlx.SqlConn, c cache.CacheConf) UserModel {
    return &customUserModel{
        defaultUserModel: newUserModel(conn, c),
    }
}

用法

$ goctl model mysql -h

NAME:
   goctl model mysql - generate mysql model"

USAGE:
   goctl model mysql command [command options] [arguments...]

COMMANDS:
   ddl         generate mysql model from ddl"
   datasource  generate model from datasource"

OPTIONS:
   --help, -h  show help

生成规则

• 默认规则

我们默认用户在建表时会创建createTime、updateTime字段(忽略大小写、下划线命名风格)且默认值均为CURRENT_TIMESTAMP，而updateTime支持ON UPDATE CURRENT_TIMESTAMP，对于这两个字段生成insert、update时会被移除，不在赋值范畴内，当然，如果你不需要这两个字段那也无大碍。

• ddl

NAME:
   goctl model mysql ddl - generate mysql model from ddl

USAGE:
   goctl model mysql ddl [command options] [arguments...]

OPTIONS:
   --src value, -s value         the path or path globbing patterns of the ddl
   --dir value, -d value         the target dir
   --style value                 the file naming format, see [https://github.com/zeromicro/go-zero/tree/master/tools/goctl/config/readme.md]
   --cache, -c                   generate code with cache [optional]
   --idea                        for idea plugin [optional]
   --database value, --db value  the name of database [optional]
   --home value                  the goctl home path of the template, --home and --remote cannot be set at the same time, if they are, --remote has higher priority
   --remote value                the remote git repo of the template, --home and --remote cannot be set at the same time, if they are, --remote has higher priority
                                 The git repo directory must be consistent with the https://github.com/zeromicro/go-zero-template directory structure
   --branch value                the branch of the remote repo, it does work with --remote

• datasource

$ goctl model mysql datasource -h                        13:40:46  羽106ms
NAME:
   goctl model mysql datasource - generate model from datasource

USAGE:
   goctl model mysql datasource [command options] [arguments...]

OPTIONS:
   --url value              the data source of database,like "root:password@tcp(127.0.0.1:3306)/database"
   --table value, -t value  the table or table globbing patterns in the database
   --cache, -c              generate code with cache [optional]
   --dir value, -d value    the target dir
   --style value            the file naming format, see [https://github.com/zeromicro/go-zero/tree/master/tools/goctl/config/readme.md]
   --idea                   for idea plugin [optional]
   --home value             the goctl home path of the template, --home and --remote cannot be set at the same time, if they are, --remote has higher priority
   --remote value           the remote git repo of the template, --home and --remote cannot be set at the same time, if they are, --remote has higher priority
                            The git repo directory must be consistent with the https://github.com/zeromicro/go-zero-template directory structure
   --branch value           the branch of the remote repo, it does work with --remote

生成代码仅基本的CURD结构。

缓存

对于缓存这一块我选择用一问一答的形式进行罗列。我想这样能够更清晰的描述model中缓存的功能。

• 缓存会缓存哪些信息？

对于主键字段缓存，会缓存整个结构体信息，而对于单索引字段（除全文索引）则缓存主键字段值。

• 数据有更新（update）操作会清空缓存吗？

会，但仅清空主键缓存的信息，why？这里就不做详细赘述了。

• 为什么不按照单索引字段生成updateByXxx和deleteByXxx的代码？

理论上是没任何问题，但是我们认为，对于model层的数据操作均是以整个结构体为单位，包括查询，我不建议只查询某部分字段（不反对），否则我们的缓存就没有意义了。

• 为什么不支持findPageLimit、findAll这种模式代码生成？

目前，我认为除了基本的CURD外，其他的代码均属于业务型代码，这个我觉得开发人员根据业务需要进行编写更好。

类型转换规则