auth

Documentation

Overview

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 request 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 ctx, err := accessController.Authorized(ctx, access); err != nil {
		if challenge, ok := err.(auth.Challenge) {
			// Let the challenge write the response.
			challenge.SetHeaders(r, w)
			w.WriteHeader(http.StatusUnauthorized)
			return
		} else {
			// Some other error.
		}
	}
}

Index

• Constants
• Variables
• func Register(name string, initFunc InitFunc) error
• func WithResources(ctx context.Context, resources []Resource) context.Context
• func WithUser(ctx context.Context, user UserInfo) context.Context
• type Access
• type AccessController
  • func GetAccessController(name string, options map[string]interface{}) (AccessController, error)
• type Challenge
• type CredentialAuthenticator
• type InitFunc
• type Resource
  • func AuthorizedResources(ctx context.Context) []Resource
• type UserInfo

Constants

const (
	// UserKey is used to get the user object from
	// a user context
	UserKey = "auth.user"

	// UserNameKey is used to get the user name from
	// a user context
	UserNameKey = "auth.user.name"
)

Variables

var (
	// ErrInvalidCredential is returned when the auth token does not authenticate correctly.
	ErrInvalidCredential = errors.New("invalid authorization credential")

	// ErrAuthenticationFailure returned when authentication fails.
	ErrAuthenticationFailure = errors.New("authentication failure")
)

Functions

func Register

func Register(name string, initFunc InitFunc) error

Register is used to register an InitFunc for an AccessController backend with the given name.

func WithResources

func WithResources(ctx context.Context, resources []Resource) context.Context

WithResources returns a context with the authorized resources.

func WithUser

func WithUser(ctx context.Context, user UserInfo) context.Context

WithUser returns a context with the authorized user info.

Types

type Access

type Access struct {
	Resource
	Action string
}

Access describes a specific action that is requested or allowed for a given resource.

type AccessController

type AccessController interface {
	// Authorized returns a non-nil error if the context is granted access and
	// returns a new authorized context. If one or more Access structs are
	// provided, the requested access will be compared with what is available
	// to the context. The given context will contain a "http.request" key with
	// a `*http.Request` value. 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. The returned context
	// object should have a "auth.user" value set to a UserInfo struct.
	Authorized(ctx context.Context, access ...Access) (context.Context, error)
}

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.

func GetAccessController

func GetAccessController(name string, options map[string]interface{}) (AccessController, error)

GetAccessController constructs an AccessController with the given options using the named backend.

type Challenge

type Challenge interface {
	error

	// SetHeaders prepares the request to conduct a challenge response by
	// adding the an HTTP challenge header on the response message. Callers
	// are expected to set the appropriate HTTP status code (e.g. 401)
	// themselves.
	SetHeaders(r *http.Request, w http.ResponseWriter)
}

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 CredentialAuthenticator

type CredentialAuthenticator interface {
	AuthenticateUser(username, password string) error
}

CredentialAuthenticator is an object which is able to authenticate credentials

type InitFunc

type InitFunc func(options map[string]interface{}) (AccessController, error)

InitFunc is the type of an AccessController factory function and is used to register the constructor for different AccesController backends.

type Resource

type Resource struct {
	Type  string
	Class string
	Name  string
}

Resource describes a resource by type and name.

func AuthorizedResources

func AuthorizedResources(ctx context.Context) []Resource

AuthorizedResources returns the list of resources which have been authorized for this request.

type UserInfo

type UserInfo struct {
	Name string
}

UserInfo carries information about an autenticated/authorized client.