Simple db miguration

migrate.go

package main

import (
	"database/sql"
	"fmt"
	"github.com/DavidHuie/gomigrate"
	_ "github.com/lib/pq"
	"os"
)

var builtAt string
var hash string

func main() {
	migrationsDir := os.Getenv("MIGRATIONS_DIR")
	dbUrl := os.Getenv("POSTGRES_URL")
	if dbUrl == "" {
		dbUrl = "postgres://localhost:5432/dbname"
	}

	if migrationsDir == "" {
		migrationsDir = "./migrations"
	}

	if len(os.Args) == 1 {
		fmt.Print("Expecting up or down\n")
		return
	}

	direction := os.Args[1]

	db, err := sql.Open("postgres", dbUrl)
	defer db.Close()
	if err != nil {
		fmt.Errorf("Error opening postgres connection: %v", err)
		return
	}

	m, err := gomigrate.NewMigrator(db, gomigrate.Postgres{}, migrationsDir)
	if err != nil {
		fmt.Errorf("Error creating migrator: %v", err)
		return
	}

	if direction == "up" {
		if err := m.Migrate(); err != nil {
			fmt.Errorf("Error with up migration: %v", err)
			return
		}
	} else if direction == "down" {
		if err := m.Rollback(); err != nil {
			fmt.Errorf("Error with down migration: %v", err)
			return
		}
	} else {
		fmt.Printf("Unknown command %s", direction)
		return
	}
}