Merge pull request #712 from stevvooe/application-structure

Carve out initial application structure

app.go

@@ -0,0 +1,94 @@
+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)
+		}
+	})
+}

app_test.go

@@ -0,0 +1,127 @@
+package registry
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+
+	"github.com/docker/docker-registry/configuration"
+)
+
+// TestAppDispatcher builds an application with a test dispatcher and ensures
+// that requests are properly dispatched and the handlers are constructed.
+// This only tests the dispatch mechanism. The underlying dispatchers must be
+// tested individually.
+func TestAppDispatcher(t *testing.T) {
+	app := &App{
+		Config: configuration.Configuration{},
+		router: v2APIRouter(),
+	}
+	server := httptest.NewServer(app)
+	router := v2APIRouter()
+
+	serverURL, err := url.Parse(server.URL)
+	if err != nil {
+		t.Fatalf("error parsing server url: %v", err)
+	}
+
+	varCheckingDispatcher := func(expectedVars map[string]string) dispatchFunc {
+		return func(ctx *Context, r *http.Request) http.Handler {
+			// Always checks the same name context
+			if ctx.Name != ctx.vars["name"] {
+				t.Fatalf("unexpected name: %q != %q", ctx.Name, "foo/bar")
+			}
+
+			// Check that we have all that is expected
+			for expectedK, expectedV := range expectedVars {
+				if ctx.vars[expectedK] != expectedV {
+					t.Fatalf("unexpected %s in context vars: %q != %q", expectedK, ctx.vars[expectedK], expectedV)
+				}
+			}
+
+			// Check that we only have variables that are expected
+			for k, v := range ctx.vars {
+				_, ok := expectedVars[k]
+
+				if !ok { // name is checked on context
+					// We have an unexpected key, fail
+					t.Fatalf("unexpected key %q in vars with value %q", k, v)
+				}
+			}
+
+			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(http.StatusOK)
+			})
+		}
+	}
+
+	// unflatten a list of variables, suitable for gorilla/mux, to a map[string]string
+	unflatten := func(vars []string) map[string]string {
+		m := make(map[string]string)
+		for i := 0; i < len(vars)-1; i = i + 2 {
+			m[vars[i]] = vars[i+1]
+		}
+
+		return m
+	}
+
+	for _, testcase := range []struct {
+		endpoint string
+		vars     []string
+	}{
+		{
+			endpoint: routeNameImageManifest,
+			vars: []string{
+				"name", "foo/bar",
+				"tag", "sometag",
+			},
+		},
+		{
+			endpoint: routeNameTags,
+			vars: []string{
+				"name", "foo/bar",
+			},
+		},
+		{
+			endpoint: routeNameLayer,
+			vars: []string{
+				"name", "foo/bar",
+				"tarsum", "thetarsum",
+			},
+		},
+		{
+			endpoint: routeNameLayerUpload,
+			vars: []string{
+				"name", "foo/bar",
+				"tarsum", "thetarsum",
+			},
+		},
+		{
+			endpoint: routeNameLayerUploadResume,
+			vars: []string{
+				"name", "foo/bar",
+				"tarsum", "thetarsum",
+				"uuid", "theuuid",
+			},
+		},
+	} {
+		app.register(testcase.endpoint, varCheckingDispatcher(unflatten(testcase.vars)))
+		route := router.GetRoute(testcase.endpoint).Host(serverURL.Host)
+		u, err := route.URL(testcase.vars...)
+
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		resp, err := http.Get(u.String())
+
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if resp.StatusCode != http.StatusOK {
+			t.Fatalf("unexpected status code: %v != %v", resp.StatusCode, http.StatusOK)
+		}
+	}
+}

context.go

@@ -0,0 +1,34 @@
+package registry
+
+import (
+	"github.com/Sirupsen/logrus"
+)
+
+// Context should contain the request specific context for use in across
+// handlers. Resources that don't need to be shared across handlers should not
+// be on this object.
+type Context struct {
+	// App points to the application structure that created this context.
+	*App
+
+	// Name is the prefix for the current request. Corresponds to the
+	// namespace/repository associated with the image.
+	Name string
+
+	// Errors is a collection of errors encountered during the request to be
+	// returned to the client API. If errors are added to the collection, the
+	// handler *must not* start the response via http.ResponseWriter.
+	Errors Errors
+
+	// TODO(stevvooe): Context would be a good place to create a
+	// representation of the "authorized resource". Perhaps, rather than
+	// having fields like "name", the context should be a set of parameters
+	// then we do routing from there.
+
+	// vars contains the extracted gorilla/mux variables that can be used for
+	// assignment.
+	vars map[string]string
+
+	// log provides a context specific logger.
+	log *logrus.Entry
+}

helpers.go

@@ -0,0 +1,20 @@
+package registry
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+// serveJSON marshals v and sets the content-type header to
+// 'application/json'. If a different status code is required, call
+// ResponseWriter.WriteHeader before this function.
+func serveJSON(w http.ResponseWriter, v interface{}) error {
+	w.Header().Set("Content-Type", "application/json")
+	enc := json.NewEncoder(w)
+
+	if err := enc.Encode(v); err != nil {
+		return err
+	}
+
+	return nil
+}

images.go

@@ -0,0 +1,46 @@
+package registry
+
+import (
+	"net/http"
+
+	"github.com/gorilla/handlers"
+)
+
+// imageManifestDispatcher takes the request context and builds the
+// appropriate handler for handling image manifest requests.
+func imageManifestDispatcher(ctx *Context, r *http.Request) http.Handler {
+	imageManifestHandler := &imageManifestHandler{
+		Context: ctx,
+		Tag:     ctx.vars["tag"],
+	}
+
+	imageManifestHandler.log = imageManifestHandler.log.WithField("tag", imageManifestHandler.Tag)
+
+	return handlers.MethodHandler{
+		"GET":    http.HandlerFunc(imageManifestHandler.GetImageManifest),
+		"PUT":    http.HandlerFunc(imageManifestHandler.PutImageManifest),
+		"DELETE": http.HandlerFunc(imageManifestHandler.DeleteImageManifest),
+	}
+}
+
+// imageManifestHandler handles http operations on image manifests.
+type imageManifestHandler struct {
+	*Context
+
+	Tag string
+}
+
+// GetImageManifest fetches the image manifest from the storage backend, if it exists.
+func (imh *imageManifestHandler) GetImageManifest(w http.ResponseWriter, r *http.Request) {
+
+}
+
+// PutImageManifest validates and stores and image in the registry.
+func (imh *imageManifestHandler) PutImageManifest(w http.ResponseWriter, r *http.Request) {
+
+}
+
+// DeleteImageManifest removes the image with the given tag from the registry.
+func (imh *imageManifestHandler) DeleteImageManifest(w http.ResponseWriter, r *http.Request) {
+
+}

layer.go

@@ -0,0 +1,34 @@
+package registry
+
+import (
+	"net/http"
+
+	"github.com/gorilla/handlers"
+)
+
+// layerDispatcher uses the request context to build a layerHandler.
+func layerDispatcher(ctx *Context, r *http.Request) http.Handler {
+	layerHandler := &layerHandler{
+		Context: ctx,
+		TarSum:  ctx.vars["tarsum"],
+	}
+
+	layerHandler.log = layerHandler.log.WithField("tarsum", layerHandler.TarSum)
+
+	return handlers.MethodHandler{
+		"GET": http.HandlerFunc(layerHandler.GetLayer),
+	}
+}
+
+// layerHandler serves http layer requests.
+type layerHandler struct {
+	*Context
+
+	TarSum string
+}
+
+// GetLayer fetches the binary data from backend storage returns it in the
+// response.
+func (lh *layerHandler) GetLayer(w http.ResponseWriter, r *http.Request) {
+
+}

layerupload.go

@@ -0,0 +1,63 @@
+package registry
+
+import (
+	"net/http"
+
+	"github.com/gorilla/handlers"
+)
+
+// layerUploadDispatcher constructs and returns the layer upload handler for
+// the given request context.
+func layerUploadDispatcher(ctx *Context, r *http.Request) http.Handler {
+	layerUploadHandler := &layerUploadHandler{
+		Context: ctx,
+		TarSum:  ctx.vars["tarsum"],
+		UUID:    ctx.vars["uuid"],
+	}
+
+	layerUploadHandler.log = layerUploadHandler.log.WithField("tarsum", layerUploadHandler.TarSum)
+
+	if layerUploadHandler.UUID != "" {
+		layerUploadHandler.log = layerUploadHandler.log.WithField("uuid", layerUploadHandler.UUID)
+	}
+
+	return handlers.MethodHandler{
+		"POST":   http.HandlerFunc(layerUploadHandler.StartLayerUpload),
+		"GET":    http.HandlerFunc(layerUploadHandler.GetUploadStatus),
+		"PUT":    http.HandlerFunc(layerUploadHandler.PutLayerChunk),
+		"DELETE": http.HandlerFunc(layerUploadHandler.CancelLayerUpload),
+	}
+}
+
+// layerUploadHandler handles the http layer upload process.
+type layerUploadHandler struct {
+	*Context
+
+	// TarSum is the unique identifier of the layer being uploaded.
+	TarSum string
+
+	// UUID identifies the upload instance for the current request.
+	UUID string
+}
+
+// StartLayerUpload begins the layer upload process and allocates a server-
+// side upload session.
+func (luh *layerUploadHandler) StartLayerUpload(w http.ResponseWriter, r *http.Request) {
+
+}
+
+// GetUploadStatus returns the status of a given upload, identified by uuid.
+func (luh *layerUploadHandler) GetUploadStatus(w http.ResponseWriter, r *http.Request) {
+
+}
+
+// PutLayerChunk receives a layer chunk during the layer upload process,
+// possible completing the upload with a checksum and length.
+func (luh *layerUploadHandler) PutLayerChunk(w http.ResponseWriter, r *http.Request) {
+
+}
+
+// CancelLayerUpload cancels an in-progress upload of a layer.
+func (luh *layerUploadHandler) CancelLayerUpload(w http.ResponseWriter, r *http.Request) {
+
+}

routes.go

@@ -5,21 +5,21 @@ import (
 )
 
 const (
-	routeNameRoot             = "root"
-	routeNameName             = "name"
-	routeNameImageManifest    = "image-manifest"
-	routeNameTags             = "tags"
-	routeNameLayer            = "layer"
-	routeNameStartLayerUpload = "start-layer-upload"
-	routeNameLayerUpload      = "layer-upload"
+	routeNameRoot              = "root"
+	routeNameName              = "name"
+	routeNameImageManifest     = "image-manifest"
+	routeNameTags              = "tags"
+	routeNameLayer             = "layer"
+	routeNameLayerUpload       = "layer-upload"
+	routeNameLayerUploadResume = "layer-upload-resume"
 )
 
 var allEndpoints = []string{
 	routeNameImageManifest,
 	routeNameTags,
 	routeNameLayer,
-	routeNameStartLayerUpload,
 	routeNameLayerUpload,
+	routeNameLayerUploadResume,
 }
 
 // v2APIRouter builds a gorilla router with named routes for the various API
@@ -59,14 +59,14 @@ func v2APIRouter() *mux.Router {
 	// POST	/v2/<name>/layer/<tarsum>/upload/	Layer Upload	Initiate an upload of the layer identified by tarsum. Requires length and a checksum parameter.
 	namedRouter.
 		Path("/layer/{tarsum}/upload/").
-		Name(routeNameStartLayerUpload)
+		Name(routeNameLayerUpload)
 
 	// GET	/v2/<name>/layer/<tarsum>/upload/<uuid>	Layer Upload	Get the status of the upload identified by tarsum and uuid.
 	// PUT	/v2/<name>/layer/<tarsum>/upload/<uuid>	Layer Upload	Upload all or a chunk of the upload identified by tarsum and uuid.
 	// DELETE	/v2/<name>/layer/<tarsum>/upload/<uuid>	Layer Upload	Cancel the upload identified by layer and uuid
 	namedRouter.
 		Path("/layer/{tarsum}/upload/{uuid}").
-		Name(routeNameLayerUpload)
+		Name(routeNameLayerUploadResume)
 
 	return router
 }

routes_test.go

@@ -76,7 +76,7 @@ func TestRouter(t *testing.T) {
 			},
 		},
 		{
-			routeName: routeNameStartLayerUpload,
+			routeName: routeNameLayerUpload,
 			expectedRouteInfo: routeInfo{
 				RequestURI: "/v2/foo/bar/layer/tarsum/upload/",
 				Vars: map[string]string{
@@ -86,7 +86,7 @@ func TestRouter(t *testing.T) {
 			},
 		},
 		{
-			routeName: routeNameLayerUpload,
+			routeName: routeNameLayerUploadResume,
 			expectedRouteInfo: routeInfo{
 				RequestURI: "/v2/foo/bar/layer/tarsum/upload/uuid",
 				Vars: map[string]string{

tags.go

@@ -0,0 +1,28 @@
+package registry
+
+import (
+	"net/http"
+
+	"github.com/gorilla/handlers"
+)
+
+// tagsDispatcher constructs the tags handler api endpoint.
+func tagsDispatcher(ctx *Context, r *http.Request) http.Handler {
+	tagsHandler := &tagsHandler{
+		Context: ctx,
+	}
+
+	return handlers.MethodHandler{
+		"GET": http.HandlerFunc(tagsHandler.GetTags),
+	}
+}
+
+// tagsHandler handles requests for lists of tags under a repository name.
+type tagsHandler struct {
+	*Context
+}
+
+// GetTags returns a json list of tags for a specific image name.
+func (th *tagsHandler) GetTags(w http.ResponseWriter, r *http.Request) {
+	// TODO(stevvooe): Implement this method.
+}

util.go

@@ -0,0 +1,27 @@
+package registry
+
+import (
+	"net/http"
+	"reflect"
+	"runtime"
+
+	"github.com/gorilla/handlers"
+)
+
+// functionName returns the name of the function fn.
+func functionName(fn interface{}) string {
+	return runtime.FuncForPC(reflect.ValueOf(fn).Pointer()).Name()
+}
+
+// resolveHandlerName attempts to resolve a nice, pretty name for the passed
+// in handler.
+func resolveHandlerName(method string, handler http.Handler) string {
+	switch v := handler.(type) {
+	case handlers.MethodHandler:
+		return functionName(v[method])
+	case http.HandlerFunc:
+		return functionName(v)
+	default:
+		return functionName(handler.ServeHTTP)
+	}
+}