distribution/app.go

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package registry
import (
"net/http"
"github.com/docker/docker-registry/configuration"
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
}
// 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: v2APIRouter(),
}
// Register the handler dispatchers.
app.register(routeNameImageManifest, imageManifestDispatcher)
app.register(routeNameLayer, layerDispatcher)
app.register(routeNameTags, tagsDispatcher)
app.register(routeNameLayerUpload, layerUploadDispatcher)
app.register(routeNameLayerUploadResume, layerUploadDispatcher)
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.
// 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) {
vars := mux.Vars(r)
context := &Context{
App: app,
Name: vars["name"],
}
// Store vars for underlying handlers.
context.vars = vars
context.log = log.WithField("name", context.Name)
handler := dispatch(context, r)
context.log.Infoln("handler", resolveHandlerName(r.Method, handler))
handler.ServeHTTP(w, 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 len(context.Errors.Errors) > 0 {
w.WriteHeader(http.StatusBadRequest)
serveJSON(w, context.Errors)
}
})
}