dvs

README

mus-stream-dvs-go

mus-stream-dvs-go provides data versioning support for the mus-stream-go serializer. With mus-stream-dvs-go we can do 2 things:

1. Marshal the current data version as if it was an old version.
2. Unmarshal the old data version as if it was the current version.

It completely repeats the structure of mus-dvs-go, and differs only in that it uses Writer, Reader interfaces rather than а slice of bytes.

Tests

Test coverage is 100%.

How To Use

You can learn more about this in the mus-dvs-go documentation.

Documentation

Index

• type DVS
  • func New[V any](reg com.Registry) DVS[V]
  • func (dvs DVS[V]) Marshal(dtm com.DTM, v V, w muss.Writer) (n int, err error)
  • func (dvs DVS[V]) Unmarshal(r muss.Reader) (dtm com.DTM, v V, n int, err error)
• type MigrationVersion
• type Version
  • func (ver Version[T, V]) MigrateCurrentAndMarshal(v V, w muss.Writer) (n int, err error)
  • func (ver Version[T, V]) UnmarshalAndMigrateOld(r muss.Reader) (v V, n int, err error)

Types

type DVS

type DVS[V any] struct {
	// contains filtered or unexported fields
}

DVS provides versioning support for the mus-stream-go serializer.

func New

func New[V any](reg com.Registry) DVS[V]

New creates a new DVS.

func (DVS[V]) Marshal

func (dvs DVS[V]) Marshal(dtm com.DTM, v V, w muss.Writer) (n int,
	err error)

Marshal migrates v to the version specified by dtm and then writes dtm + resulting v version encoding.

Returns the number of written bytes and one of the ErrUnknownDTM, ErrWrongTypeVersion or Writer errors.

func (DVS[V]) Unmarshal

func (dvs DVS[V]) Unmarshal(r muss.Reader) (dtm com.DTM, v V, n int,
	err error)

Unmarshal unmarshals dtm + data, and then migrates data to the version specified by dtm.

Returns the number of read bytes and one of the ErrUnknownDTM, ErrWrongTypeVersion or Reader errors.

type MigrationVersion

type MigrationVersion[V any] interface {
	MigrateCurrentAndMarshal(v V, w muss.Writer) (n int, err error)
	UnmarshalAndMigrateOld(r muss.Reader) (v V, n int, err error)
}

MigrationVersion represents a generic type version for Registry that can be migrated.

It contains methods to support all mus-stream-dvs-go functionality.

type Version

type Version[T any, V any] struct {
	DTS            dts.DTS[T]
	MigrateOld     com.MigrateOld[T, V]
	MigrateCurrent com.MigrateCurrent[V, T]
}

Version is an implementation of the MigrationVersion interface.

func (Version[T, V]) MigrateCurrentAndMarshal

func (ver Version[T, V]) MigrateCurrentAndMarshal(v V, w muss.Writer) (n int,
	err error)

func (Version[T, V]) UnmarshalAndMigrateOld

func (ver Version[T, V]) UnmarshalAndMigrateOld(r muss.Reader) (v V, n int,
	err error)