diff --git a/database/sqlmigrate/mymigrate/go.mod b/database/sqlmigrate/mymigrate/go.mod new file mode 100644 index 0000000..3b3b1bb --- /dev/null +++ b/database/sqlmigrate/mymigrate/go.mod @@ -0,0 +1,10 @@ +module github.com/therootcompany/golib/database/sqlmigrate/mymigrate + +go 1.26.1 + +require ( + github.com/go-sql-driver/mysql v1.9.3 + github.com/therootcompany/golib/database/sqlmigrate v1.0.0 +) + +require filippo.io/edwards25519 v1.1.0 // indirect diff --git a/database/sqlmigrate/mymigrate/go.sum b/database/sqlmigrate/mymigrate/go.sum new file mode 100644 index 0000000..c4e25ae --- /dev/null +++ b/database/sqlmigrate/mymigrate/go.sum @@ -0,0 +1,6 @@ +filippo.io/edwards25519 v1.1.0 h1:FNf4tywRC1HmFuKW5xopWpigGjJKiJSV0Cqo0cJWDaA= +filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4VDT4= +github.com/go-sql-driver/mysql v1.9.3 h1:U/N249h2WzJ3Ukj8SowVFjdtZKfu9vlLZxjPXV1aweo= +github.com/go-sql-driver/mysql v1.9.3/go.mod h1:qn46aNg1333BRMNU69Lq93t8du/dwxI64Gl8i5p1WMU= +github.com/therootcompany/golib/database/sqlmigrate v1.0.0 h1:vehFGUBdv/su0jDzSNxYN7N7i1KE3l2QJDf4x9LXhwQ= +github.com/therootcompany/golib/database/sqlmigrate v1.0.0/go.mod h1:7PQUjwT78Hx+SftcIKI2PH4zSFlrSO0V9h618PJqC38= diff --git a/database/sqlmigrate/mymigrate/mymigrate.go b/database/sqlmigrate/mymigrate/mymigrate.go new file mode 100644 index 0000000..64226f8 --- /dev/null +++ b/database/sqlmigrate/mymigrate/mymigrate.go @@ -0,0 +1,101 @@ +// Package mymigrate implements sqlmigrate.Migrator for MySQL and MariaDB +// using database/sql with github.com/go-sql-driver/mysql. +// +// The *sql.DB must be opened with multiStatements=true in the DSN; +// without it, multi-statement migration files will fail. New returns +// an error if multi-statement support is not detected: +// +// db, err := sql.Open("mysql", "user:pass@tcp(host:3306)/dbname?multiStatements=true") +// +// MySQL and MariaDB do not support transactional DDL. Statements like +// CREATE TABLE and ALTER TABLE cause an implicit commit, so if a migration +// fails partway through, earlier DDL statements in that migration will +// already be committed. DML-only migrations are fully transactional. +package mymigrate + +import ( + "context" + "database/sql" + "errors" + "fmt" + + "github.com/go-sql-driver/mysql" + + "github.com/therootcompany/golib/database/sqlmigrate" +) + +// Migrator implements sqlmigrate.Migrator using a *sql.DB with MySQL/MariaDB. +type Migrator struct { + DB *sql.DB +} + +// New creates a Migrator from the given database handle. +// Returns an error if the connection does not support multi-statement +// queries (multiStatements=true must be set in the DSN). +func New(db *sql.DB) (*Migrator, error) { + // Probe for multi-statement support. Without it, migration files + // that contain more than one statement silently execute only the first. + if _, err := db.Exec("DO 1; DO 1"); err != nil { + return nil, fmt.Errorf("mymigrate: connection requires multiStatements=true in DSN: %w", err) + } + return &Migrator{DB: db}, nil +} + +var _ sqlmigrate.Migrator = (*Migrator)(nil) + +// ExecUp runs the up migration SQL in a transaction. DDL statements +// (CREATE, ALTER, DROP) are implicitly committed by MySQL; see package docs. +func (m *Migrator) ExecUp(ctx context.Context, mig sqlmigrate.Migration) error { + return m.exec(ctx, mig.Up) +} + +// ExecDown runs the down migration SQL in a transaction. DDL statements +// (CREATE, ALTER, DROP) are implicitly committed by MySQL; see package docs. +func (m *Migrator) ExecDown(ctx context.Context, mig sqlmigrate.Migration) error { + return m.exec(ctx, mig.Down) +} + +func (m *Migrator) exec(ctx context.Context, sqlStr string) error { + tx, err := m.DB.BeginTx(ctx, nil) + if err != nil { + return fmt.Errorf("%w: begin: %w", sqlmigrate.ErrExecFailed, err) + } + defer tx.Rollback() //nolint:errcheck + + if _, err := tx.ExecContext(ctx, sqlStr); err != nil { + return fmt.Errorf("%w: exec: %w", sqlmigrate.ErrExecFailed, err) + } + + if err := tx.Commit(); err != nil { + return fmt.Errorf("%w: commit: %w", sqlmigrate.ErrExecFailed, err) + } + + return nil +} + +// Applied returns all applied migrations from the _migrations table. +// Returns an empty slice if the table does not exist (MySQL error 1146). +func (m *Migrator) Applied(ctx context.Context) ([]sqlmigrate.AppliedMigration, error) { + rows, err := m.DB.QueryContext(ctx, "SELECT id, name FROM _migrations ORDER BY name") + if err != nil { + if mysqlErr, ok := errors.AsType[*mysql.MySQLError](err); ok && mysqlErr.Number == 1146 { + return nil, nil + } + return nil, fmt.Errorf("%w: %w", sqlmigrate.ErrQueryApplied, err) + } + defer rows.Close() + + var applied []sqlmigrate.AppliedMigration + for rows.Next() { + var a sqlmigrate.AppliedMigration + if err := rows.Scan(&a.ID, &a.Name); err != nil { + return nil, fmt.Errorf("%w: scanning row: %w", sqlmigrate.ErrQueryApplied, err) + } + applied = append(applied, a) + } + if err := rows.Err(); err != nil { + return nil, fmt.Errorf("%w: reading rows: %w", sqlmigrate.ErrQueryApplied, err) + } + + return applied, nil +} diff --git a/database/sqlmigrate/sqlmigrate.go b/database/sqlmigrate/sqlmigrate.go index c627c8f..c51cbd8 100644 --- a/database/sqlmigrate/sqlmigrate.go +++ b/database/sqlmigrate/sqlmigrate.go @@ -50,10 +50,15 @@ type Status struct { // Migrator executes migrations. Implementations handle the // database-specific or output-specific details. +// +// Database backends should wrap each migration in a transaction when the +// database supports transactional DDL (e.g. PostgreSQL). For databases +// that do not (e.g. MySQL), the transaction provides atomicity for DML +// only — DDL statements are implicitly committed by the engine. type Migrator interface { // ExecUp runs the up migration. For database migrators this executes - // m.Up in a transaction. For shell migrators this outputs a command - // referencing the .up.sql file. + // m.Up in a transaction (see package docs for DDL caveats). For shell + // migrators this outputs a command referencing the .up.sql file. ExecUp(ctx context.Context, m Migration) error // ExecDown runs the down migration.