go/pgutil/migrate.go

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2024-11-11 05:36:55 +00:00
package pgutil
import (
"database/sql"
"embed"
"errors"
"fmt"
"path/filepath"
"sort"
)
const initMigrationTableQuery = `
CREATE TABLE IF NOT EXISTS migrations(filename TEXT NOT NULL PRIMARY KEY);`
const insertMigrationQuery = `INSERT INTO migrations(filename) VALUES($1)`
const checkMigrationAppliedQuery = `SELECT EXISTS(SELECT 1 FROM migrations WHERE filename=$1)`
func Migrate(db *sql.DB, migrationFS embed.FS) error {
return WithTx(db, func(tx *sql.Tx) error {
if _, err := tx.Exec(initMigrationTableQuery); err != nil {
return err
}
dirs, err := migrationFS.ReadDir(".")
if err != nil {
return err
}
if len(dirs) != 1 {
return errors.New("expected a single migrations directory")
}
if !dirs[0].IsDir() {
return fmt.Errorf("unexpected non-directory in migration FS: %s", dirs[0].Name())
}
dirName := dirs[0].Name()
files, err := migrationFS.ReadDir(dirName)
if err != nil {
return err
}
// Sort sql files by name.
sort.Slice(files, func(i, j int) bool {
return files[i].Name() < files[j].Name()
})
for _, dirEnt := range files {
if !dirEnt.Type().IsRegular() {
return fmt.Errorf("unexpected non-regular file in migration fs: %s", dirEnt.Name())
}
var (
name = dirEnt.Name()
exists bool
)
err := tx.QueryRow(checkMigrationAppliedQuery, name).Scan(&exists)
if err != nil {
return err
}
if exists {
continue
}
migration, err := migrationFS.ReadFile(filepath.Join(dirName, name))
if err != nil {
return err
}
if _, err := tx.Exec(string(migration)); err != nil {
return fmt.Errorf("migration %s failed: %v", name, err)
}
if _, err := tx.Exec(insertMigrationQuery, name); err != nil {
return err
}
}
return nil
})
}