distribution/registry/app.go

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package registry
import (
"fmt"
"net/http"
"github.com/docker/distribution/api/v2"
"github.com/docker/distribution/auth"
"github.com/docker/distribution/configuration"
"github.com/docker/distribution/storage"
"github.com/docker/distribution/storagedriver"
"github.com/docker/distribution/storagedriver/factory"
log "github.com/Sirupsen/logrus"
"github.com/gorilla/mux"
)
// App is a global registry application object. Shared resources can be placed
// on this object that will be accessible from all requests. Any writable
// fields should be protected.
type App struct {
Config configuration.Configuration
router *mux.Router
// driver maintains the app global storage driver instance.
driver storagedriver.StorageDriver
// services contains the main services instance for the application.
services *storage.Services
tokenProvider tokenProvider
accessController auth.AccessController
}
// NewApp takes a configuration and returns a configured app, ready to serve
// requests. The app only implements ServeHTTP and can be wrapped in other
// handlers accordingly.
func NewApp(configuration configuration.Configuration) *App {
app := &App{
Config: configuration,
router: v2.Router(),
}
// Register the handler dispatchers.
app.register(v2.RouteNameBase, func(ctx *Context, r *http.Request) http.Handler {
return http.HandlerFunc(apiBase)
})
app.register(v2.RouteNameManifest, imageManifestDispatcher)
app.register(v2.RouteNameTags, tagsDispatcher)
app.register(v2.RouteNameBlob, layerDispatcher)
app.register(v2.RouteNameBlobUpload, layerUploadDispatcher)
app.register(v2.RouteNameBlobUploadChunk, layerUploadDispatcher)
driver, err := factory.Create(configuration.Storage.Type(), configuration.Storage.Parameters())
if err != nil {
// TODO(stevvooe): Move the creation of a service into a protected
// method, where this is created lazily. Its status can be queried via
// a health check.
panic(err)
}
app.driver = driver
app.services = storage.NewServices(app.driver)
app.tokenProvider = newHMACTokenProvider(configuration.HTTP.Secret)
authType := configuration.Auth.Type()
if authType != "" {
accessController, err := auth.GetAccessController(configuration.Auth.Type(), configuration.Auth.Parameters())
if err != nil {
panic(fmt.Sprintf("unable to configure authorization (%s): %v", authType, err))
}
app.accessController = accessController
}
return app
}
func (app *App) ServeHTTP(w http.ResponseWriter, r *http.Request) {
app.router.ServeHTTP(w, r)
}
// register a handler with the application, by route name. The handler will be
// passed through the application filters and context will be constructed at
// request time.
func (app *App) register(routeName string, dispatch dispatchFunc) {
// TODO(stevvooe): This odd dispatcher/route registration is by-product of
// some limitations in the gorilla/mux router. We are using it to keep
// routing consistent between the client and server, but we may want to
// replace it with manual routing and structure-based dispatch for better
// control over the request execution.
app.router.GetRoute(routeName).Handler(app.dispatcher(dispatch))
}
// dispatchFunc takes a context and request and returns a constructed handler
// for the route. The dispatcher will use this to dynamically create request
// specific handlers for each endpoint without creating a new router for each
// request.
type dispatchFunc func(ctx *Context, r *http.Request) http.Handler
// TODO(stevvooe): dispatchers should probably have some validation error
// chain with proper error reporting.
// singleStatusResponseWriter only allows the first status to be written to be
// the valid request status. The current use case of this class should be
// factored out.
type singleStatusResponseWriter struct {
http.ResponseWriter
status int
}
func (ssrw *singleStatusResponseWriter) WriteHeader(status int) {
if ssrw.status != 0 {
return
}
ssrw.status = status
ssrw.ResponseWriter.WriteHeader(status)
}
// dispatcher returns a handler that constructs a request specific context and
// handler, using the dispatch factory function.
func (app *App) dispatcher(dispatch dispatchFunc) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
context := app.context(r)
if err := app.authorized(w, r, context); err != nil {
return
}
context.log = log.WithField("name", context.Name)
handler := dispatch(context, r)
ssrw := &singleStatusResponseWriter{ResponseWriter: w}
context.log.Infoln("handler", resolveHandlerName(r.Method, handler))
handler.ServeHTTP(ssrw, r)
// Automated error response handling here. Handlers may return their
// own errors if they need different behavior (such as range errors
// for layer upload).
if context.Errors.Len() > 0 {
if ssrw.status == 0 {
w.WriteHeader(http.StatusBadRequest)
}
serveJSON(w, context.Errors)
}
})
}
// context constructs the context object for the application. This only be
// called once per request.
func (app *App) context(r *http.Request) *Context {
vars := mux.Vars(r)
context := &Context{
App: app,
Name: vars["name"],
urlBuilder: v2.NewURLBuilderFromRequest(r),
}
// Store vars for underlying handlers.
context.vars = vars
return context
}
// authorized checks if the request can proceed with with request access-
// level. If it cannot, the method will return an error.
func (app *App) authorized(w http.ResponseWriter, r *http.Request, context *Context) error {
if app.accessController == nil {
return nil // access controller is not enabled.
}
var accessRecords []auth.Access
if context.Name != "" {
resource := auth.Resource{
Type: "repository",
Name: context.Name,
}
switch r.Method {
case "GET", "HEAD":
accessRecords = append(accessRecords,
auth.Access{
Resource: resource,
Action: "pull",
})
case "POST", "PUT", "PATCH":
accessRecords = append(accessRecords,
auth.Access{
Resource: resource,
Action: "pull",
},
auth.Access{
Resource: resource,
Action: "push",
})
case "DELETE":
// DELETE access requires full admin rights, which is represented
// as "*". This may not be ideal.
accessRecords = append(accessRecords,
auth.Access{
Resource: resource,
Action: "*",
})
}
} else {
// Only allow the name not to be set on the base route.
route := mux.CurrentRoute(r)
if route == nil || route.GetName() != v2.RouteNameBase {
// For this to be properly secured, context.Name must always be set
// for a resource that may make a modification. The only condition
// under which name is not set and we still allow access is when the
// base route is accessed. This section prevents us from making that
// mistake elsewhere in the code, allowing any operation to proceed.
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.WriteHeader(http.StatusForbidden)
var errs v2.Errors
errs.Push(v2.ErrorCodeUnauthorized)
serveJSON(w, errs)
}
}
if err := app.accessController.Authorized(r, accessRecords...); err != nil {
switch err := err.(type) {
case auth.Challenge:
w.Header().Set("Content-Type", "application/json; charset=utf-8")
err.ServeHTTP(w, r)
var errs v2.Errors
errs.Push(v2.ErrorCodeUnauthorized, accessRecords)
serveJSON(w, errs)
default:
// This condition is a potential security problem either in
// the configuration or whatever is backing the access
// controller. Just return a bad request with no information
// to avoid exposure. The request should not proceed.
context.log.Errorf("error checking authorization: %v", err)
w.WriteHeader(http.StatusBadRequest)
}
return err
}
return nil
}
// apiBase implements a simple yes-man for doing overall checks against the
// api. This can support auth roundtrips to support docker login.
func apiBase(w http.ResponseWriter, r *http.Request) {
const emptyJSON = "{}"
// Provide a simple /v2/ 200 OK response with empty json response.
w.Header().Set("Content-Type", "application/json; charset=utf-8")
w.Header().Set("Content-Length", fmt.Sprint(len(emptyJSON)))
fmt.Fprint(w, emptyJSON)
}