forked from TrueCloudLab/distribution
107 lines
3.8 KiB
Go
107 lines
3.8 KiB
Go
// Package auth defines a standard interface for request access controllers.
|
|
//
|
|
// An access controller has a simple interface with a single `Authorized`
|
|
// method which checks that a given request is authorized to perform one or
|
|
// more actions on one or more resources. This method should return a non-nil
|
|
// error if the requset is not authorized.
|
|
//
|
|
// An implementation registers its access controller by name with a constructor
|
|
// which accepts an options map for configuring the access controller.
|
|
//
|
|
// options := map[string]interface{}{"sillySecret": "whysosilly?"}
|
|
// accessController, _ := auth.GetAccessController("silly", options)
|
|
//
|
|
// This `accessController` can then be used in a request handler like so:
|
|
//
|
|
// func updateOrder(w http.ResponseWriter, r *http.Request) {
|
|
// orderNumber := r.FormValue("orderNumber")
|
|
// resource := auth.Resource{Type: "customerOrder", Name: orderNumber}
|
|
// access := auth.Access{Resource: resource, Action: "update"}
|
|
//
|
|
// if err := accessController.Authorized(r, access); err != nil {
|
|
// if challenge, ok := err.(auth.Challenge) {
|
|
// // Let the challenge write the response.
|
|
// challenge.ServeHTTP(w, r)
|
|
// } else {
|
|
// // Some other error.
|
|
// }
|
|
// }
|
|
// }
|
|
//
|
|
package auth
|
|
|
|
import (
|
|
"fmt"
|
|
"net/http"
|
|
)
|
|
|
|
// Resource describes a resource by type and name.
|
|
type Resource struct {
|
|
Type string
|
|
Name string
|
|
}
|
|
|
|
// Access describes a specific action that is
|
|
// requested or allowed for a given recource.
|
|
type Access struct {
|
|
Resource
|
|
Action string
|
|
}
|
|
|
|
// Challenge is a special error type which is used for HTTP 401 Unauthorized
|
|
// responses and is able to write the response with WWW-Authenticate challenge
|
|
// header values based on the error.
|
|
type Challenge interface {
|
|
error
|
|
// ServeHTTP prepares the request to conduct the appropriate challenge
|
|
// response. For most implementations, simply calling ServeHTTP should be
|
|
// sufficient. Because no body is written, users may write a custom body after
|
|
// calling ServeHTTP, but any headers must be written before the call and may
|
|
// be overwritten.
|
|
ServeHTTP(w http.ResponseWriter, r *http.Request)
|
|
}
|
|
|
|
// AccessController controls access to registry resources based on a request
|
|
// and required access levels for a request. Implementations can support both
|
|
// complete denial and http authorization challenges.
|
|
type AccessController interface {
|
|
// Authorized returns non-nil if the request is granted access. If one or
|
|
// more Access structs are provided, the requested access will be compared
|
|
// with what is available to the request. If the error is non-nil, access
|
|
// should always be denied. The error may be of type Challenge, in which
|
|
// case the caller may have the Challenge handle the request or choose
|
|
// what action to take based on the Challenge header or response status.
|
|
Authorized(req *http.Request, access ...Access) error
|
|
}
|
|
|
|
// InitFunc is the type of an AccessController factory function and is used
|
|
// to register the contsructor for different AccesController backends.
|
|
type InitFunc func(options map[string]interface{}) (AccessController, error)
|
|
|
|
var accessControllers map[string]InitFunc
|
|
|
|
func init() {
|
|
accessControllers = make(map[string]InitFunc)
|
|
}
|
|
|
|
// Register is used to register an InitFunc for
|
|
// an AccessController backend with the given name.
|
|
func Register(name string, initFunc InitFunc) error {
|
|
if _, exists := accessControllers[name]; exists {
|
|
return fmt.Errorf("name already registered: %s", name)
|
|
}
|
|
|
|
accessControllers[name] = initFunc
|
|
|
|
return nil
|
|
}
|
|
|
|
// GetAccessController constructs an AccessController
|
|
// with the given options using the named backend.
|
|
func GetAccessController(name string, options map[string]interface{}) (AccessController, error) {
|
|
if initFunc, exists := accessControllers[name]; exists {
|
|
return initFunc(options)
|
|
}
|
|
|
|
return nil, fmt.Errorf("no access controller registered with name: %s", name)
|
|
}
|