package migrations import ( // stdlib "database/sql" "log" "os" "strconv" // other "github.com/pressly/goose" ) func Initialize() { log.Println("Initializing database migrations...") _ = goose.SetDialect("postgres") goose.AddNamedMigration("1_create_users_table.go", CreateUsersTableUp, CreateUsersTableDown) // Migrations should be registered here. } func Migrate(db *sql.DB) { log.Println("Starting database migration procedure...") // Prepare migrations configuration. var action = "UP" actionFromEnv, actionFound := os.LookupEnv("DATABASE_ACTION") if actionFound { log.Println("Migration action override: " + actionFromEnv) action = actionFromEnv } else { log.Println("Executing default migration action (UP)") } var count int64 countFromEnv, countFound := os.LookupEnv("DATABASE_COUNT") if countFound { log.Println("Migration count override: " + countFromEnv) countAsInt, err := strconv.ParseInt(countFromEnv, 10, 64) if err != nil { log.Fatalln("Failed to convert count gathered from DATABASE_COUNT to integer") } count = countAsInt } else { log.Println("Applying or rollback this count of migrations: " + countFromEnv + ". 0 - all.") } // Execute migrations. var err error currentDBVersion, gooseerr := goose.GetDBVersion(db) if gooseerr != nil { log.Fatalln("Failed to get database version: " + gooseerr.Error()) } log.Println("Current database version obtained: " + strconv.Itoa(int(currentDBVersion))) if action == "UP" && count == 0 { log.Println("Applying all unapplied migrations...") err = goose.Up(db, ".") } else if action == "UP" && count != 0 { newVersion := currentDBVersion + count log.Println("Migrating database to specific version: " + strconv.Itoa(int(newVersion))) err = goose.UpTo(db, ".", newVersion) } else if action == "DOWN" && count == 0 { log.Println("Downgrading database to zero state, you'll need to re-apply migrations!") err = goose.Down(db, ".") log.Fatalln("Database downgraded to zero state. You have to re-apply migrations") } else if action == "DOWN" && count != 0 { newVersion := currentDBVersion - count log.Println("Downgrading database to specific version: " + strconv.Itoa(int(newVersion))) err = goose.DownTo(db, ".", newVersion) } else { log.Fatalln("Unsupported set of migration parameters, cannot continue: " + action + "/" + countFromEnv) } if err != nil { log.Fatalln("Failed to execute migration sequence: " + err.Error()) } log.Println("Database migrated successfully") }