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hnnsgstfssnandGitHub a7fbb937e9 Add pkger source driver support (#377)
* Add pkger source driver support

As go-bindata has been abandoned [1] there are open requests, #116, for
alternative sources with similar functionality. The Buffalo project [2]
created packr and recently pkger [3] was announced [4] with the
intention to supersede packr.

This change adds support for using pkger as a source.

The implementation relies on httpfs.PartialDriver for pretty much all
functionality.

[1] https://github.com/jteeuwen/go-bindata/issues/5
[2] https://gobuffalo.io/
[3] https://github.com/markbates/pkger
[4] https://blog.gobuffalo.io/introducing-pkger-static-file-embedding-in-go-1ce76dc79c65

* pkger: rename Instance to Pkger

* pkger: make WithInstance accept *Pkger

* pkger: refactor and add access to global pkging.Pkger instance

* pkger: fix typo and cleanup debug logging
2020-04-21 16:43:53 -07:00

84 lines
2.2 KiB
Go

package pkger
import (
"fmt"
"net/http"
stdurl "net/url"
"github.com/golang-migrate/migrate/v4/source"
"github.com/golang-migrate/migrate/v4/source/httpfs"
"github.com/markbates/pkger"
"github.com/markbates/pkger/pkging"
)
func init() {
source.Register("pkger", &Pkger{})
}
// Pkger is a source.Driver that reads migrations from instances of
// pkging.Pkger.
type Pkger struct {
httpfs.PartialDriver
}
// Open implements source.Driver. The path component of url will be used as the
// relative location of migrations. The returned driver will use the package
// scoped pkger.Open to access migrations. The relative root and any
// migrations must be added to the global pkger.Pkger instance by calling
// pkger.Apply. Refer to Pkger documentation for more information.
func (p *Pkger) Open(url string) (source.Driver, error) {
u, err := stdurl.Parse(url)
if err != nil {
return nil, err
}
// wrap pkger to implement http.FileSystem.
fs := fsFunc(func(name string) (http.File, error) {
f, err := pkger.Open(name)
if err != nil {
return nil, err
}
return f.(http.File), nil
})
if err := p.Init(fs, u.Path); err != nil {
return nil, fmt.Errorf("failed to init driver with relative path %q: %w", u.Path, err)
}
return p, nil
}
// WithInstance returns a source.Driver that is backed by an instance of
// pkging.Pkger. The relative location of migrations is indicated by path. The
// path must exist on the pkging.Pkger instance for the driver to initialize
// successfully.
func WithInstance(instance pkging.Pkger, path string) (source.Driver, error) {
if instance == nil {
return nil, fmt.Errorf("expected instance of pkging.Pkger")
}
// wrap pkger to implement http.FileSystem.
fs := fsFunc(func(name string) (http.File, error) {
f, err := instance.Open(name)
if err != nil {
return nil, err
}
return f.(http.File), nil
})
var p Pkger
if err := p.Init(fs, path); err != nil {
return nil, fmt.Errorf("failed to init driver with relative path %q: %w", path, err)
}
return &p, nil
}
type fsFunc func(name string) (http.File, error)
// Open implements http.FileSystem.
func (f fsFunc) Open(name string) (http.File, error) {
return f(name)
}