Feature Flags

The framework provides a collection of code-generation features that be added or removed using flags.

Usage

Feature flags can be provided either by CLI flags or as arguments to the gen package.

CLI

go run entgo.io/ent/cmd/ent generate --feature privacy,entql ./ent/schema

Go

// +build ignore
package main
import (
    "log"
    "text/template"
    "entgo.io/ent/entc"
    "entgo.io/ent/entc/gen"
)
func main() {
    err := entc.Generate("./schema", &gen.Config{
        Features: []gen.Feature{
            gen.FeaturePrivacy,
            gen.FeatureEntQL,
        },
        Templates: []*gen.Template{
            gen.MustParse(gen.NewTemplate("static").
                Funcs(template.FuncMap{"title": strings.ToTitle}).
                ParseFiles("template/static.tmpl")),
        },
    })
    if err != nil {
        log.Fatalf("running ent codegen: %v", err)
    }
}

List of Features

Privacy Layer

The privacy layer allows configuring privacy policy for queries and mutations of entities in the database.

This option can added to a project using the --feature privacy flag, and its full documentation exists in the privacy page.

EntQL Filtering

The entql option provides a generic and dynamic filtering capability at runtime for the different query builders.

This option can be added to a project using the --feature entql flag, and more information about it exists in the privacy page.

Auto-Solve Merge Conflicts

The schema/snapshot option tells entc (ent codegen) to store a snapshot of the latest schema in an internal package, and use it to automatically solve merge conflicts when user’s schema can’t be built.

This option can be added to a project using the --feature schema/snapshot flag, but please see ent/ent/issues/852 to get more context about it.

Schema Config

The sql/schemaconfig option lets you pass alternate SQL database names to models. This is useful when your models don’t all live under one database and are spread out across different schemas.

This option can be added to a project using the --feature sql/schemaconfig flag. Once you generate the code, you can now use a new option as such:

c, err := ent.Open(dialect, conn, ent.AlternateSchema(ent.SchemaConfig{
    User: "usersdb",
    Car: "carsdb",
}))
c.User.Query().All(ctx) // SELECT * FROM `usersdb`.`users`
c.Car.Query().All(ctx)  // SELECT * FROM `carsdb`.`cars`

Row-level Locks

The sql/lock option lets configure row-level locking using the SQL SELECT ... FOR {UPDATE | SHARE} syntax.

This option can be added to a project using the --feature sql/lock flag.

tx, err := client.Tx(ctx)
if err != nil {
    log.Fatal(err)
}
tx.Pet.Query().
    Where(pet.Name(name)).
    ForUpdate().
    Only(ctx)
tx.Pet.Query().
    Where(pet.ID(id)).
    ForShare(
        sql.WithLockTables(pet.Table),
        sql.WithLockAction(sql.NoWait),
    ).
    Only(ctx)

Custom SQL Modifiers

The sql/modifier option lets add custom SQL modifiers to the builders and mutate the statements before they are executed.

This option can be added to a project using the --feature sql/modifier flag.

Example 1

client.Pet.
    Query().
    Modify(func(s *sql.Selector) {
        s.Select("SUM(LENGTH(name))")
    }).
    IntX(ctx)

The above code will produce the following SQL query:

SELECT SUM(LENGTH(name)) FROM `pet`

Example 2

var p1 []struct {
    ent.Pet
    NameLength int `sql:"length"`
}
client.Pet.Query().
    Order(ent.Asc(pet.FieldID)).
    Modify(func(s *sql.Selector) {
        s.AppendSelect("LENGTH(name)")
    }).
    ScanX(ctx, &p1)

The above code will produce the following SQL query:

SELECT `pet`.*, LENGTH(name) FROM `pet` ORDER BY `pet`.`id` ASC

Example 3

var v []struct {
    Count     int       `json:"count"`
    Price     int       `json:"price"`
    CreatedAt time.Time `json:"created_at"`
}
client.User.
    Query().
    Where(
        user.CreatedAtGT(x),
        user.CreatedAtLT(y),
    ).
    Modify(func(s *sql.Selector) {
        s.Select(
            sql.As(sql.Count("*"), "count"),
            sql.As(sql.Sum("price"), "price"),
            sql.As("DATE(created_at)", "created_at"),
        ).
        GroupBy("DATE(created_at)").
        OrderBy(sql.Desc("DATE(created_at)"))
    }).
    ScanX(ctx, &v)

The above code will produce the following SQL query:

SELECT
    COUNT(*) AS `count`,
    SUM(`price`) AS `price`,
    DATE(created_at) AS `created_at`
FROM
    `users`
WHERE
    `created_at` > x AND `created_at` < y
GROUP BY
    DATE(created_at)
ORDER BY
    DATE(created_at) DESC

Example 4

var gs []struct {
    ent.Group
    UsersCount int `sql:"users_count"`
}
client.Group.Query().
    Order(ent.Asc(group.FieldID)).
    Modify(func(s *sql.Selector) {
        t := sql.Table(group.UsersTable)
        s.LeftJoin(t).
            On(
                s.C(group.FieldID),
                t.C(group.UsersPrimaryKey[1]),
            ).
            // Append the "users_count" column to the selected columns.
            AppendSelect(
                sql.As(sql.Count(t.C(group.UsersPrimaryKey[1])), "users_count"),
            ).
            GroupBy(s.C(group.FieldID))
    }).
    ScanX(ctx, &gs)

The above code will produce the following SQL query:

SELECT
    `groups`.*,
    COUNT(`t1`.`group_id`) AS `users_count`
FROM
    `groups` LEFT JOIN `user_groups` AS `t1`
ON
    `groups`.`id` = `t1`.`group_id`
GROUP BY
    `groups`.`id`
ORDER BY
    `groups`.`id` ASC

Upsert

The sql/upsert option lets configure upsert and bulk-upsert logic using the SQL ON CONFLICT / ON DUPLICATE KEY syntax. For full documentation, go to the Upsert API.

This option can be added to a project using the --feature sql/upsert flag.

// Use the new values that were set on create.
id, err := client.User.
    Create().
    SetAge(30).
    SetName("Ariel").
    OnConflict().
    UpdateNewValues().
    ID(ctx)
// In PostgreSQL, the conflict target is required.
err := client.User.
    Create().
    SetAge(30).
    SetName("Ariel").
    OnConflictColumns(user.FieldName).
    UpdateNewValues().
    Exec(ctx)
// Bulk upsert is also supported.
client.User.
    CreateBulk(builders...).
    OnConflict(
        sql.ConflictWhere(...),
        sql.UpdateWhere(...),
    ).
    UpdateNewValues().
    Exec(ctx)
// INSERT INTO "users" (...) VALUES ... ON CONFLICT WHERE ... DO UPDATE SET ... WHERE ...