go__ent_demo/main.go

//zlint:file-ignore U1000 this is a variable source demo
package main

import (
	"context"
	"errors"
	"fmt"
	"log"
	"os"
	"time"

	"entgo.io/ent/dialect/sql"
	_ "github.com/go-sql-driver/mysql"
	// _ "github.com/mattn/go-sqlite3"

	"code.osinet.fr/fgm/go__ent_demo/ent"
)

const (
	name   = "a8m"
	dbPath = "ent.db"
)

func userDemo(ctx context.Context, client *ent.Client) {
	u, err := CreateUser(ctx, client)
	if err != nil {
		log.Fatalf("failed creating user: %v", err)
	}
	fmt.Println("created: ", u)

	u, err = QueryUser(ctx, client)
	if err != nil {
		log.Fatalf("failed querying user: %v", err)
	}
	fmt.Println("found: ", u)
}

func edgeDemo(ctx context.Context, client *ent.Client) {
	u, err := CreateCars(ctx, client)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("owner: ", u)
}

func setupSQLite() (*ent.Client, error) {
	if err := os.Remove(dbPath); err != nil && !errors.Is(err, os.ErrNotExist) {
		return nil, fmt.Errorf("failed cleaning up old DB: %w", err)
	}

	// client, err := ent.Open("sqlite3", "file:ent.db?mode=memory&cache=shared&_fk=1")
	client, err := ent.Open("sqlite3", "file:"+dbPath+"?cache=shared&_fk=1")
	if err != nil {
		return nil, fmt.Errorf("failed opening connection to SQLite: %w", err)
	}
	return client, err
}

func setupMariaDB() (*ent.Client, error) {
	user := os.Getenv("ENTDEMO_USER")
	pass := os.Getenv("ENTDEMO_PASS")
	drv, err := sql.Open("mysql", fmt.Sprintf("%s:%s@/go_entdemo?parseTime=true", user, pass))
	if err != nil {
		return nil, fmt.Errorf("failed opening connection to DB server: %w", err)
	}
	db := drv.DB()
	db.SetMaxIdleConns(10)
	db.SetMaxOpenConns(100)
	db.SetConnMaxLifetime(time.Hour)

	for _, tbl := range []string{"cars", "group_users", "groups", "users"} {
		_, err := db.Exec("DROP TABLE " + tbl)
		if err != nil {
			return nil, fmt.Errorf("dropping table %s: %w", tbl, err)
		}
	}
	return ent.NewClient(ent.Driver(drv)), nil
}

func setup(ctx context.Context) (client *ent.Client, err error) {
	// if client, err = setupSQLite(); err != nil {
	// 	return nil, err
	// }
	if client, err = setupMariaDB(); err != nil {
		return nil, err
	}
	// Run the auto migration tool.
	if err := client.Schema.Create(ctx); err != nil {
		return nil, fmt.Errorf("failed creating schema resources: %w", err)
	}
	return client, nil
}

func main() {
	ctx := context.Background()
	client, err := setup(ctx)
	if err != nil {
		log.Fatalln(err)
	}
	defer client.Close()

	// userDemo(ctx, client)
	// edgeDemo(ctx, client)
	if err := CreateGraph(ctx, client); err != nil {
		log.Fatalf("failed creating graph: %c", err)
	}
	if err := QueryGithub(ctx, client); err != nil {
		log.Fatalf("failed querying github cars: %v", err)
	}
	if err := QueryArielCars(ctx, client); err != nil {
		log.Fatalf("failed querying Ariel's cars: %v", err)
	}
	if err := QueryGroupWithUsers(ctx, client); err != nil {
		log.Fatalf("failed querying groups with users: %v", err)
	}
}