github.com/lusis/distribution@v2.0.1+incompatible/registry/storage/driver/middleware/storagemiddleware.go (about)

     1  package storagemiddleware
     2  
     3  import (
     4  	"fmt"
     5  
     6  	storagedriver "github.com/docker/distribution/registry/storage/driver"
     7  )
     8  
     9  // InitFunc is the type of a StorageMiddleware factory function and is
    10  // used to register the constructor for different StorageMiddleware backends.
    11  type InitFunc func(storageDriver storagedriver.StorageDriver, options map[string]interface{}) (storagedriver.StorageDriver, error)
    12  
    13  var storageMiddlewares map[string]InitFunc
    14  
    15  // Register is used to register an InitFunc for
    16  // a StorageMiddleware backend with the given name.
    17  func Register(name string, initFunc InitFunc) error {
    18  	if storageMiddlewares == nil {
    19  		storageMiddlewares = make(map[string]InitFunc)
    20  	}
    21  	if _, exists := storageMiddlewares[name]; exists {
    22  		return fmt.Errorf("name already registered: %s", name)
    23  	}
    24  
    25  	storageMiddlewares[name] = initFunc
    26  
    27  	return nil
    28  }
    29  
    30  // Get constructs a StorageMiddleware with the given options using the named backend.
    31  func Get(name string, options map[string]interface{}, storageDriver storagedriver.StorageDriver) (storagedriver.StorageDriver, error) {
    32  	if storageMiddlewares != nil {
    33  		if initFunc, exists := storageMiddlewares[name]; exists {
    34  			return initFunc(storageDriver, options)
    35  		}
    36  	}
    37  
    38  	return nil, fmt.Errorf("no storage middleware registered with name: %s", name)
    39  }