distribution/docs/handlers/app.go

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package handlers
import (
"fmt"
"net"
"net/http"
"os"
"code.google.com/p/go-uuid/uuid"
"github.com/docker/distribution"
"github.com/docker/distribution/configuration"
ctxu "github.com/docker/distribution/context"
"github.com/docker/distribution/notifications"
"github.com/docker/distribution/registry/api/v2"
"github.com/docker/distribution/registry/auth"
"github.com/docker/distribution/registry/storage"
storagedriver "github.com/docker/distribution/registry/storage/driver"
"github.com/docker/distribution/registry/storage/driver/factory"
"github.com/gorilla/mux"
"golang.org/x/net/context"
)
// 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 {
context.Context
Config configuration.Configuration
// InstanceID is a unique id assigned to the application on each creation.
// Provides information in the logs and context to identify restarts.
InstanceID string
router *mux.Router // main application router, configured with dispatchers
driver storagedriver.StorageDriver // driver maintains the app global storage driver instance.
registry distribution.Registry // registry is the primary registry backend for the app instance.
accessController auth.AccessController // main access controller for application
// events contains notification related configuration.
events struct {
sink notifications.Sink
source notifications.SourceRecord
}
layerHandler storage.LayerHandler // allows dispatch of layer serving to external provider
}
// Value intercepts calls context.Context.Value, returning the current app id,
// if requested.
func (app *App) Value(key interface{}) interface{} {
switch key {
case "app.id":
return app.InstanceID
}
return app.Context.Value(key)
}
// 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(ctx context.Context, configuration configuration.Configuration) *App {
app := &App{
Config: configuration,
Context: ctx,
InstanceID: uuid.New(),
router: v2.RouterWithPrefix(configuration.HTTP.Prefix),
}
app.Context = ctxu.WithLogger(app.Context, ctxu.GetLogger(app, "app.id"))
// 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)
var err error
app.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.configureEvents(&configuration)
app.registry = storage.NewRegistryWithDriver(app.driver)
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
}
layerHandlerType := configuration.LayerHandler.Type()
if layerHandlerType != "" {
lh, err := storage.GetLayerHandler(layerHandlerType, configuration.LayerHandler.Parameters(), app.driver)
if err != nil {
panic(fmt.Sprintf("unable to configure layer handler (%s): %v", layerHandlerType, err))
}
app.layerHandler = lh
}
return app
}
// 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))
}
// configureEvents prepares the event sink for action.
func (app *App) configureEvents(configuration *configuration.Configuration) {
// Configure all of the endpoint sinks.
var sinks []notifications.Sink
for _, endpoint := range configuration.Notifications.Endpoints {
if endpoint.Disabled {
ctxu.GetLogger(app).Infof("endpoint %s disabled, skipping", endpoint.Name)
continue
}
ctxu.GetLogger(app).Infof("configuring endpoint %v (%v), timeout=%s, headers=%v", endpoint.Name, endpoint.URL, endpoint.Timeout, endpoint.Headers)
endpoint := notifications.NewEndpoint(endpoint.Name, endpoint.URL, notifications.EndpointConfig{
Timeout: endpoint.Timeout,
Threshold: endpoint.Threshold,
Backoff: endpoint.Backoff,
Headers: endpoint.Headers,
})
sinks = append(sinks, endpoint)
}
// NOTE(stevvooe): Moving to a new queueing implementation is as easy as
// replacing broadcaster with a rabbitmq implementation. It's recommended
// that the registry instances also act as the workers to keep deployment
// simple.
app.events.sink = notifications.NewBroadcaster(sinks...)
// Populate registry event source
hostname, err := os.Hostname()
if err != nil {
hostname = configuration.HTTP.Addr
} else {
// try to pick the port off the config
_, port, err := net.SplitHostPort(configuration.HTTP.Addr)
if err == nil {
hostname = net.JoinHostPort(hostname, port)
}
}
app.events.source = notifications.SourceRecord{
Addr: hostname,
InstanceID: app.InstanceID,
}
}
func (app *App) ServeHTTP(w http.ResponseWriter, r *http.Request) {
defer r.Body.Close() // ensure that request body is always closed.
// Set a header with the Docker Distribution API Version for all responses.
w.Header().Add("Docker-Distribution-API-Version", "registry/2.0")
app.router.ServeHTTP(w, r)
}
// 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)
}
func (ssrw *singleStatusResponseWriter) Flush() {
if flusher, ok := ssrw.ResponseWriter.(http.Flusher); ok {
flusher.Flush()
}
}
// 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(w, r)
defer func() {
ctxu.GetResponseLogger(context).Infof("response completed")
}()
if err := app.authorized(w, r, context); err != nil {
ctxu.GetLogger(context).Errorf("error authorizing context: %v", err)
return
}
if app.nameRequired(r) {
repository, err := app.registry.Repository(context, getName(context))
if err != nil {
ctxu.GetLogger(context).Errorf("error resolving repository: %v", err)
switch err := err.(type) {
case distribution.ErrRepositoryUnknown:
context.Errors.Push(v2.ErrorCodeNameUnknown, err)
case distribution.ErrRepositoryNameInvalid:
context.Errors.Push(v2.ErrorCodeNameInvalid, err)
}
w.WriteHeader(http.StatusBadRequest)
serveJSON(w, context.Errors)
return
}
// assign and decorate the authorized repository with an event bridge.
context.Repository = notifications.Listen(
repository,
app.eventBridge(context, r))
}
handler := dispatch(context, r)
ssrw := &singleStatusResponseWriter{ResponseWriter: w}
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(w http.ResponseWriter, r *http.Request) *Context {
ctx := ctxu.WithRequest(app, r)
ctx, w = ctxu.WithResponseWriter(ctx, w)
ctx = ctxu.WithVars(ctx, r)
ctx = ctxu.WithLogger(ctx, ctxu.GetRequestLogger(ctx))
ctx = ctxu.WithLogger(ctx, ctxu.GetLogger(ctx,
"vars.name",
"vars.reference",
"vars.digest",
"vars.uuid"))
context := &Context{
App: app,
Context: ctx,
urlBuilder: v2.NewURLBuilderFromRequest(r),
}
return context
}
// authorized checks if the request can proceed with access to the requested
// repository. If it succeeds, the context may access the requested
// repository. An error will be returned if access is not available.
func (app *App) authorized(w http.ResponseWriter, r *http.Request, context *Context) error {
ctxu.GetLogger(context).Debug("authorizing request")
repo := getName(context)
if app.accessController == nil {
return nil // access controller is not enabled.
}
var accessRecords []auth.Access
if repo != "" {
accessRecords = appendAccessRecords(accessRecords, r.Method, repo)
} else {
// Only allow the name not to be set on the base route.
if app.nameRequired(r) {
// For this to be properly secured, repo 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)
return fmt.Errorf("forbidden: no repository name")
}
}
ctx, err := app.accessController.Authorized(context.Context, accessRecords...)
if 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.
ctxu.GetLogger(context).Errorf("error checking authorization: %v", err)
w.WriteHeader(http.StatusBadRequest)
}
return err
}
// TODO(stevvooe): This pattern needs to be cleaned up a bit. One context
// should be replaced by another, rather than replacing the context on a
// mutable object.
context.Context = ctx
return nil
}
// eventBridge returns a bridge for the current request, configured with the
// correct actor and source.
func (app *App) eventBridge(ctx *Context, r *http.Request) notifications.Listener {
actor := notifications.ActorRecord{
Name: getUserName(ctx, r),
}
request := notifications.NewRequestRecord(ctxu.GetRequestID(ctx), r)
return notifications.NewBridge(ctx.urlBuilder, app.events.source, actor, request, app.events.sink)
}
// nameRequired returns true if the route requires a name.
func (app *App) nameRequired(r *http.Request) bool {
route := mux.CurrentRoute(r)
return route == nil || route.GetName() != v2.RouteNameBase
}
// 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)
}
// appendAccessRecords checks the method and adds the appropriate Access records to the records list.
func appendAccessRecords(records []auth.Access, method string, repo string) []auth.Access {
resource := auth.Resource{
Type: "repository",
Name: repo,
}
switch method {
case "GET", "HEAD":
records = append(records,
auth.Access{
Resource: resource,
Action: "pull",
})
case "POST", "PUT", "PATCH":
records = append(records,
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.
records = append(records,
auth.Access{
Resource: resource,
Action: "*",
})
}
return records
}