applied-migration.go

package schema

import (
	"fmt"
	"time"
)

// AppliedMigration represents a successfully-executed migration. It embeds
// Migration, and adds fields for execution results. This type is what
// records persisted in the schema_migrations table align with.
type AppliedMigration struct {
	Migration

	// Checksum is the MD5 hash of the Script for this migration
	Checksum string

	// ExecutionTimeInMillis is populated after the migration is run, indicating
	// how much time elapsed while the Script was executing.
	ExecutionTimeInMillis int64

	// AppliedAt is the time at which this particular migration's Script began
	// executing (not when it completed executing).
	AppliedAt time.Time
}

// GetAppliedMigrations retrieves all already-applied migrations in a map keyed
// by the migration IDs
func (m Migrator) GetAppliedMigrations(db Queryer) (applied map[string]*AppliedMigration, err error) {
	applied = make(map[string]*AppliedMigration)

	// Get the raw data from the Dialect
	migrations, err := m.Dialect.GetAppliedMigrations(m.ctx, db, m.QuotedTableName())
	if err != nil {
		err = fmt.Errorf("Failed to GetAppliedMigrations. Did somebody change the structure of the %s table? %w", m.QuotedTableName(), err)
		return applied, err
	}

	// Re-index into a map
	for _, migration := range migrations {
		applied[migration.ID] = migration
	}

	return applied, err
}