migrator

README

Migrator

Opinionated database migration library for Go applications.

Supported databases

• Postgres

When building your project using this library, make sure you pass build tags to compile only the driver you want to use. Example: go build -tags postgres or go test -tags postgres

Documentation

Index

• Variables
• type AssetDirFunc
• type AssetFunc
• type DBType
• type Migration
  • func DecodeFile(f string, assetFunc AssetFunc) (*Migration, error)
• type Migrator
  • func NewMigrator(db *sql.DB, dbType DBType, assetFunc AssetFunc, assetDirFunc AssetDirFunc) (Migrator, error)

Variables

var (
	// ErrBadFilenameFormat is returned if a migration file does not conform
	// with the expected name patter. Ex: 001_my-migration_up.sql
	ErrBadFilenameFormat = errors.New("bad-filename-format")
	// ErrInvalidDirection is returned if the direction of a migration is other
	// than 'up' or 'down'
	ErrInvalidDirection = errors.New("invalid-migration-direction")
	// ErrDBNotSupported is returned when trying to create a migrator instance
	// for an unsupported database.
	ErrDBNotSupported = errors.New("database-not-supported")
	// ErrInvalidDB is returned when a nil *sql.DB pointer is passed to NewMigrator
	ErrInvalidDB = errors.New("invalid-database-handle")
	// ErrMigrationFailed is returned when a migration failed to run
	ErrMigrationFailed = errors.New("migration-failed")
)

Types

type AssetDirFunc

type AssetDirFunc func(path string) ([]string, error)

AssetDirFunc is the type that defines the function to access specific embedded dirs

type AssetFunc

type AssetFunc func(path string) ([]byte, error)

AssetFunc is the type that defines the function to access specific embedded files

type DBType

type DBType string

DBType defines a type for specifying the databasse to use during migration.

const (
	Postgres DBType = "postgres"
)

Supported databases.

type Migration

type Migration struct {
	ID        string
	Name      string
	Filename  string `db:"filename"`
	Up        string
	Down      string
	Status    string
	CreatedAt time.Time `db:"created_at"`
	UpdatedAt time.Time `db:"updated_at"`
}

Migration represents an actual migration file.

func DecodeFile

func DecodeFile(f string, assetFunc AssetFunc) (*Migration, error)

DecodeFile takes a sql file and returns a Migration instance

type Migrator

type Migrator interface {
	// Init initializes migrations table in the given database.
	Init() error
	// Migrate applies all migrations that hasn't been applied.
	Migrate() error
	// Redo undos specific migrations and applies them again. By default
	// if no parameter is specified, it will redo the latest migration.
	Redo(n ...uint) error
	// Rollback reverts the last migration if not parameter is specified.
	Rollback(n ...uint) error
	// Migrations returns the list of migrations currently applied to the database.
	Migrations(ids ...string) ([]*Migration, error)
	// Up applies a specific migration version.
	Up(version string) error
	// Down rolls back or takes down a specific migration version.
	Down(version string) error
}

Migrator defines the set of functions used by this package.

func NewMigrator

func NewMigrator(db *sql.DB, dbType DBType, assetFunc AssetFunc, assetDirFunc AssetDirFunc) (Migrator, error)

NewMigrator creates a new instance of the migration process, based on the database type provided.