101 lines
3.0 KiB
Go

// Package pgmigrate implements sqlmigrate.Migrator for PostgreSQL via pgx/v5.
//
// # Multi-tenant schemas
//
// For schema-based multi-tenancy, set search_path on the pool's connection
// config so all migrations target the correct schema:
//
// import "github.com/jackc/pgx/v5"
//
// config, _ := pgxpool.ParseConfig(pgURL)
// config.AfterConnect = func(ctx context.Context, conn *pgx.Conn) error {
// _, err := conn.Exec(ctx, fmt.Sprintf("SET search_path TO %s", pgx.Identifier{schema}.Sanitize()))
// return err
// }
// pool, _ := pgxpool.NewWithConfig(ctx, config)
// runner := pgmigrate.New(pool)
//
// Each schema gets its own _migrations table, so tenants are migrated
// independently. The sql-migrate CLI supports this via TENANT_SCHEMA;
// see the CLI help for details.
package pgmigrate
import (
"context"
"errors"
"fmt"
"github.com/jackc/pgx/v5/pgconn"
"github.com/jackc/pgx/v5/pgxpool"
"github.com/therootcompany/golib/database/sqlmigrate"
)
// Migrator implements sqlmigrate.Migrator using a pgxpool.Pool.
type Migrator struct {
Pool *pgxpool.Pool
}
// New creates a Migrator from the given pool.
func New(pool *pgxpool.Pool) *Migrator {
return &Migrator{Pool: pool}
}
// verify interface compliance at compile time
var _ sqlmigrate.Migrator = (*Migrator)(nil)
// ExecUp runs the up migration SQL inside a PostgreSQL transaction.
func (r *Migrator) ExecUp(ctx context.Context, m sqlmigrate.Migration) error {
return r.execInTx(ctx, m.Up)
}
// ExecDown runs the down migration SQL inside a PostgreSQL transaction.
func (r *Migrator) ExecDown(ctx context.Context, m sqlmigrate.Migration) error {
return r.execInTx(ctx, m.Down)
}
func (r *Migrator) execInTx(ctx context.Context, sql string) error {
tx, err := r.Pool.Begin(ctx)
if err != nil {
return fmt.Errorf("%w: begin: %w", sqlmigrate.ErrExecFailed, err)
}
defer tx.Rollback(ctx) //nolint:errcheck
if _, err := tx.Exec(ctx, sql); err != nil {
return fmt.Errorf("%w: exec: %w", sqlmigrate.ErrExecFailed, err)
}
if err := tx.Commit(ctx); 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 (PG error 42P01).
func (r *Migrator) Applied(ctx context.Context) ([]sqlmigrate.AppliedMigration, error) {
rows, err := r.Pool.Query(ctx, "SELECT id, name FROM _migrations ORDER BY name")
if err != nil {
if pgErr, ok := errors.AsType[*pgconn.PgError](err); ok && pgErr.Code == "42P01" {
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
}