migrator

type Configuration struct {
	// DatabaseConnectionString is the connection string where the migrations
	// will be ran against.
	DatabaseConnectionString string

	// MigrationsDir is the directory where the migration SQL scripts
	// are stored.
	MigrationsDir string

	// RollbacksDir is the directory where the rollback SQL scripts
	// are stored.
	RollbacksDir string

	// MigrationToRollback is the migration that needs to be rolled back. This
	// is useful when a development mistake may have been made.
	MigrationToRollback string
}

type DatabaseServicer interface {
	// BeginTransaction creates a transaction in the implementing database
	// servicer.
	BeginTransaction() error

	// CommitTransaction ends the created transaction providing there is one
	// and commits it to the database.
	CommitTransaction() error

	// RanMigrations retrieves all previously ran migrations.
	RanMigrations() ([]RanMigration, error)

	// RemoveMigrationHistory removes the specified migration from the
	// history table.
	RemoveMigrationHistory(m Migration) error

	// RollbackTransaction ends the created transaction providing there is one
	// and rolls it back, ensuring there are no changes to the database made.
	RollbackTransaction() error

	// RollbackMigration rolls back the specified migration and removes it
	// from the RanMigrations table.
	RollbackMigration(m Migration) error

	// RunMigration runs the specified migration against the current database.
	RunMigration(m Migration) error

	// TryCreateHistoryTable creates the migration history table if it does
	// not already exist. The boolean return value indicates whether or not
	// the table had to be created.
	TryCreateHistoryTable() (bool, error)

	// WriteMigrationHistory writes that a migration has been ran into the
	// migration history table.
	WriteMigrationHistory(m Migration) error
}

type ErrCreatingHistoryTable struct {
	// contains filtered or unexported fields
}

type ErrInvalidMigrationID struct {
	// contains filtered or unexported fields
}

type ErrMissingRollbackFile struct {
	// contains filtered or unexported fields
}

type ErrReadingFile struct {
	// contains filtered or unexported fields
}

type ErrRunningMigration struct {
	// contains filtered or unexported fields
}

type ErrRunningRollback struct {
	// contains filtered or unexported fields
}

type ErrSearchingDir struct {
	// contains filtered or unexported fields
}

type LogServicer interface {
	// Printf formats a string with a set of parameters before printing it to
	// the output.
	Printf(format string, v ...interface{})
}

type Migration struct {
	// ID represents where the migration is in the order of those to be
	// completed.
	ID int

	// FileName is the file name of the migration.
	FileName string

	// FileContents is the contents of the migration to run.
	FileContents []byte

	// Rollback is the rollback file for the current migration. There must
	// always be one; otherwise an error will occur.
	Rollback Rollback
}

type Migrator struct {
	// Config is the configuration object of the
	Config Configuration

	// DatabaseServicer is the service that performs all database operations.
	DatabaseServicer DatabaseServicer

	// LogServicer is the service that will perform all logging routines.
	// This abstraction exists only to decouple the application from the
	// implementation of log.Logger.
	LogServicer LogServicer
}

type RanMigration struct {
	// ID is the identifier of the migration that was ran.
	ID int

	// FileName is the name of the migration.
	FileName string

	// Ran is when the migration was ran into the database.
	Ran time.Time
}

type Rollback struct {
	// FileName is the file name of the rollback.
	FileName string

	// FileContents is the contents of the associated rollback.
	FileContents []byte
}