Files

104 lines
1.8 KiB
Go

package version
import (
"sort"
)
// AfterPatchCallback is called after each time a migration is successfully applied (up) or reverted (down).
type AfterPatchCallback func(applied, next *Version)
// Migration maps provide a simple way to store and run versioned 'patch' functions.
type Migration map[string]Patch
// Down reverts all patches in reverse version order.
func (m Migration) Down(after AfterPatchCallback) error {
versions, err := m.Versions()
if err != nil {
return err
}
for i := len(versions); i > 0; i-- {
v := versions[i-1]
patch := m[v.Text]
if err := patch.Down(); err != nil {
return err
}
if after != nil {
var next *Version
if i > 1 {
next = versions[i-1]
}
after(v, next)
}
}
return nil
}
// Match tests versions against a constraint and returns a new migration map of matching versions only.
func (m Migration) Match(constraints ...*Constraint) (Migration, error) {
l, err := m.Versions()
if err != nil {
return nil, err
}
l = l.Match(constraints...)
m2 := Migration{}
for _, v := range l {
m2[v.Text] = m[v.Text]
}
return m2, nil
}
// Up executes all patches in version order.
func (m Migration) Up(after AfterPatchCallback) error {
versions, err := m.Versions()
if err != nil {
return err
}
for i, v := range versions {
patch := m[v.Text]
if err := patch.Up(); err != nil {
return err
}
if after != nil {
var next *Version
if i < len(versions)-1 {
next = versions[i+1]
}
after(v, next)
}
}
return nil
}
// Versions returns a List of all versions in the migration map.
func (m Migration) Versions() (List, error) {
l := List{}
for str := range m {
v, err := Parse(str)
if err != nil {
return nil, err
}
l = append(l, v)
}
sort.Stable(l)
return l, nil
}
type Patch struct {
Down func() error
Up func() error
}