distribution/registry/storage/driver/middleware/storagemiddleware.go
David Lawrence 4acda57e05 Refactoring cloudfactory layer handler into a more generic storage
middleware concept.

This also breaks the dependency the storage package had on goamz
Signed-off-by: David Lawrence <david.lawrence@docker.com> (github: endophage)
2015-03-11 08:56:28 -07:00

40 lines
1.4 KiB
Go

package storagemiddleware
import (
"fmt"
storagedriver "github.com/docker/distribution/registry/storage/driver"
)
// InitFunc is the type of a StorageMiddleware factory function and is
// used to register the contsructor for different StorageMiddleware backends.
type InitFunc func(storageDriver storagedriver.StorageDriver, options map[string]interface{}) (storagedriver.StorageDriver, error)
var storageMiddlewares map[string]InitFunc
// RegisterStorageMiddleware is used to register an StorageMiddlewareInitFunc for
// a StorageMiddleware backend with the given name.
func RegisterStorageMiddleware(name string, initFunc InitFunc) error {
if storageMiddlewares == nil {
storageMiddlewares = make(map[string]InitFunc)
}
if _, exists := storageMiddlewares[name]; exists {
return fmt.Errorf("name already registered: %s", name)
}
storageMiddlewares[name] = initFunc
return nil
}
// GetStorageMiddleware constructs a StorageMiddleware
// with the given options using the named backend.
func GetStorageMiddleware(name string, options map[string]interface{}, storageDriver storagedriver.StorageDriver) (storagedriver.StorageDriver, error) {
if storageMiddlewares != nil {
if initFunc, exists := storageMiddlewares[name]; exists {
return initFunc(storageDriver, options)
}
}
return nil, fmt.Errorf("no storage middleware registered with name: %s", name)
}