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Documentation
¶
Overview ¶
Package migrate reads migrations from sources and runs them against configs. Sources are defined by the `source.Driver` and configs by the `config.Driver` interface. The driver interfaces are kept "dumb", all migration logic is kept in this package.
Index ¶
- Variables
- func FilterCustomQuery(u *nurl.URL) *nurl.URL
- type ErrShortLimit
- type Logger
- type Migrate
- func New(sourceURL, configURL string) (*Migrate, error)
- func NewWithDatabaseInstance(sourceURL string, configName string, configInstance config.Driver) (*Migrate, error)
- func NewWithInstance(sourceName string, sourceInstance source.Driver, configName string, ...) (*Migrate, error)
- func NewWithSourceInstance(sourceName string, sourceInstance source.Driver, configURL string) (*Migrate, error)
- func (m *Migrate) Close() (source error, config error)
- func (m *Migrate) Down() error
- func (m *Migrate) Drop() error
- func (m *Migrate) Migrate(version uint) error
- func (m *Migrate) Run(migration ...*Migration) error
- func (m *Migrate) Steps(n int) error
- func (m *Migrate) Up() error
- func (m *Migrate) Version() (version uint, err error)
- type Migration
- type MultiErrordeprecated
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var ( ErrNoChange = errors.New("no change") ErrNilVersion = errors.New("no migration") ErrInvalidVersion = errors.New("version must be >= -1") ErrLocked = errors.New("config locked") ErrLockTimeout = errors.New("timeout: can't acquire config lock") )
var DefaultBufferSize = uint(100000)
DefaultBufferSize sets the in memory buffer size (in Bytes) for every pre-read migration (see DefaultPrefetchMigrations).
var DefaultLockTimeout = 15 * time.Second
DefaultLockTimeout sets the max time a config driver has to acquire a lock.
var DefaultPrefetchMigrations = uint(10)
DefaultPrefetchMigrations sets the number of migrations to pre-read from the source. This is helpful if the source is remote, but has little effect for a local source (i.e. file system). Please note that this setting has a major impact on the memory usage, since each pre-read migration is buffered in memory. See DefaultBufferSize.
Functions ¶
Types ¶
type ErrShortLimit ¶
type ErrShortLimit struct {
Short uint
}
ErrShortLimit is an error returned when not enough migrations can be returned by a source for a given limit.
func (ErrShortLimit) Error ¶
func (e ErrShortLimit) Error() string
Error implements the error interface.
type Logger ¶
type Logger interface {
// Printf is like fmt.Printf
Printf(format string, v ...interface{})
// Verbose should return true when verbose logging output is wanted
Verbose() bool
}
Logger is an interface so you can pass in your own logging implementation.
type Migrate ¶
type Migrate struct {
// Log accepts a Logger interface
Log Logger
// GracefulStop accepts `true` and will stop executing migrations
// as soon as possible at a safe break point, so that the config
// is not corrupted.
GracefulStop chan bool
// PrefetchMigrations defaults to DefaultPrefetchMigrations,
// but can be set per Migrate instance.
PrefetchMigrations uint
// LockTimeout defaults to DefaultLockTimeout,
// but can be set per Migrate instance.
LockTimeout time.Duration
// contains filtered or unexported fields
}
func New ¶
New returns a new Migrate instance from a source URL and a config URL. The URL scheme is defined by each driver.
func NewWithDatabaseInstance ¶
func NewWithDatabaseInstance(sourceURL string, configName string, configInstance config.Driver) (*Migrate, error)
NewWithDatabaseInstance returns a new Migrate instance from a source URL and an existing config instance. The source URL scheme is defined by each driver. Use any string that can serve as an identifier during logging as configName. You are responsible for closing the underlying config client if necessary.
func NewWithInstance ¶
func NewWithInstance(sourceName string, sourceInstance source.Driver, configName string, configInstance config.Driver) (*Migrate, error)
NewWithInstance returns a new Migrate instance from an existing source and config instance. Use any string that can serve as an identifier during logging as sourceName and configName. You are responsible for closing down the underlying source and config client if necessary.
func NewWithSourceInstance ¶
func NewWithSourceInstance(sourceName string, sourceInstance source.Driver, configURL string) (*Migrate, error)
NewWithSourceInstance returns a new Migrate instance from an existing source instance and a config URL. The config URL scheme is defined by each driver. Use any string that can serve as an identifier during logging as sourceName. You are responsible for closing the underlying source client if necessary.
func (*Migrate) Down ¶
Down looks at the currently active migration version and will migrate all the way down (applying all down migrations).
func (*Migrate) Migrate ¶
Migrate looks at the currently active migration version, then migrates either up or down to the specified version.
func (*Migrate) Run ¶
Run runs any migration provided by you against the config. It does not check any currently active version in config. Usually you don't need this function at all. Use Migrate, Steps, Up or Down instead.
func (*Migrate) Steps ¶
Steps looks at the currently active migration version. It will migrate up if n > 0, and down if n < 0.
type Migration ¶
type Migration struct {
// Identifier can be any string to help identifying
// the migration in the source.
Identifier string
// Version is the version of this migration.
Version uint
// TargetVersion is the migration version after this migration
// has been applied to the config.
// Can be -1, implying that this is a NilVersion.
TargetVersion int
// Body holds an io.ReadCloser to the source.
Body io.ReadCloser
// BufferedBody holds an buffered io.Reader to the underlying Body.
BufferedBody io.Reader
// BufferSize defaults to DefaultBufferSize
BufferSize uint
// Scheduled is the time when the migration was scheduled/ queued.
Scheduled time.Time
// StartedBuffering is the time when buffering of the migration source started.
StartedBuffering time.Time
// FinishedBuffering is the time when buffering of the migration source finished.
FinishedBuffering time.Time
// FinishedReading is the time when the migration source is fully read.
FinishedReading time.Time
// BytesRead holds the number of Bytes read from the migration source.
BytesRead int64
// contains filtered or unexported fields
}
Migration holds information about a migration. It is initially created from data coming from the source and then used when run against the config.
func NewMigration ¶
func NewMigration(body io.ReadCloser, identifier string, version uint, targetVersion int) (*Migration, error)
NewMigration returns a new Migration and sets the body, identifier, version and targetVersion. Body can be nil, which turns this migration into a "NilMigration". If no identifier is provided, it will default to "<empty>". targetVersion can be -1, implying it is a NilVersion.
What is a NilMigration? Usually each migration version coming from source is expected to have an Up and Down migration. This is not a hard requirement though, leading to a situation where only the Up or Down migration is present. So let's say the user wants to migrate up to a version that doesn't have the actual Up migration, in that case we still want to apply the version, but with an empty body. We are calling that a NilMigration, a migration with an empty body.
What is a NilVersion? NilVersion is a const(-1). When running down migrations and we are at the last down migration, there is no next down migration, the targetVersion should be nil. Nil in this case is represented by -1 (because type int).
Example ¶
// Create a dummy migration body, this is coming from the source usually.
body := io.NopCloser(strings.NewReader("dumy migration that creates users table"))
// Create a new Migration that represents version 1486686016.
// Once this migration has been applied to the config, the new
// migration version will be 1486689359.
migr, err := NewMigration(body, "create_users_table", 1486686016, 1486689359)
if err != nil {
log.Fatal(err)
}
fmt.Print(migr.LogString())
Output: 1486686016/u create_users_table
Example (NilMigration) ¶
// Create a new Migration that represents a NilMigration.
// Once this migration has been applied to the config, the new
// migration version will be 1486689359.
migr, err := NewMigration(nil, "", 1486686016, 1486689359)
if err != nil {
log.Fatal(err)
}
fmt.Print(migr.LogString())
Output: 1486686016/u <empty>
Example (NilVersion) ¶
// Create a dummy migration body, this is coming from the source usually.
body := io.NopCloser(strings.NewReader("dumy migration that deletes users table"))
// Create a new Migration that represents version 1486686016.
// This is the last available down migration, so the migration version
// will be -1, meaning NilVersion once this migration ran.
migr, err := NewMigration(body, "drop_users_table", 1486686016, -1)
if err != nil {
log.Fatal(err)
}
fmt.Print(migr.LogString())
Output: 1486686016/d drop_users_table
func (*Migration) Buffer ¶
Buffer buffers Body up to BufferSize. Calling this function blocks. Call with goroutine.
type MultiError
deprecated
type MultiError struct {
Errs []error
}
MultiError holds multiple errors.
Deprecated: Use github.com/hashicorp/go-multierror instead
func NewMultiError
deprecated
func NewMultiError(errs ...error) MultiError
NewMultiError returns an error type holding multiple errors.
Deprecated: Use github.com/hashicorp/go-multierror instead
func (MultiError) Error ¶
func (m MultiError) Error() string
Error implements error. Multiple errors are concatenated with 'and's.
Source Files
Directories
¶
| Path | Synopsis |
|---|---|
|
Package config provides the Driver interface.
|
Package config provides the Driver interface. |
|
Package source provides the Source interface.
|
Package source provides the Source interface. |
|
iofs
Package iofs provides the Go 1.16+ io/fs#FS driver.
|
Package iofs provides the Go 1.16+ io/fs#FS driver. |
|
testing
Package testing has the source tests.
|
Package testing has the source tests. |