Catalog for V2 API Implementation

This change adds a basic catalog endpoint to the API, which returns a list,
or partial list, of all of the repositories contained in the registry.  Calls
to this endpoint are somewhat expensive, as every call requires walking a
large part of the registry.

Instead, to maintain a list of repositories, you would first call the catalog
endpoint to get an initial list, and then use the events API to maintain
any future repositories.

Signed-off-by: Patrick Devine <patrick.devine@docker.com>

docs/handlers/api_test.go

@@ -60,6 +60,85 @@ func TestCheckAPI(t *testing.T) {
 	}
 }
 
+func TestCatalogAPI(t *testing.T) {
+	env := newTestEnv(t)
+
+	values := url.Values{"last": []string{""}, "n": []string{"100"}}
+
+	catalogURL, err := env.builder.BuildCatalogURL(values)
+	if err != nil {
+		t.Fatalf("unexpected error building catalog url: %v", err)
+	}
+
+	// -----------------------------------
+	// try to get an empty catalog
+	resp, err := http.Get(catalogURL)
+	if err != nil {
+		t.Fatalf("unexpected error issuing request: %v", err)
+	}
+	defer resp.Body.Close()
+
+	checkResponse(t, "issuing catalog api check", resp, http.StatusOK)
+
+	var ctlg struct {
+		Repositories []string `json:"repositories"`
+	}
+
+	dec := json.NewDecoder(resp.Body)
+	if err := dec.Decode(&ctlg); err != nil {
+		t.Fatalf("error decoding fetched manifest: %v", err)
+	}
+
+	// we haven't pushed anything to the registry yet
+	if ctlg.Repositories != nil {
+		t.Fatalf("repositories has unexpected values")
+	}
+
+	if resp.Header.Get("Link") != "" {
+		t.Fatalf("repositories has more data when none expected")
+	}
+
+	// -----------------------------------
+	// push something to the registry and try again
+	imageName := "foo/bar"
+	createRepository(env, t, imageName, "sometag")
+
+	resp, err = http.Get(catalogURL)
+	if err != nil {
+		t.Fatalf("unexpected error issuing request: %v", err)
+	}
+	defer resp.Body.Close()
+
+	checkResponse(t, "issuing catalog api check", resp, http.StatusOK)
+
+	dec = json.NewDecoder(resp.Body)
+	if err = dec.Decode(&ctlg); err != nil {
+		t.Fatalf("error decoding fetched manifest: %v", err)
+	}
+
+	if len(ctlg.Repositories) != 1 {
+		t.Fatalf("repositories has unexpected values")
+	}
+
+	if !contains(ctlg.Repositories, imageName) {
+		t.Fatalf("didn't find our repository '%s' in the catalog", imageName)
+	}
+
+	if resp.Header.Get("Link") != "" {
+		t.Fatalf("repositories has more data when none expected")
+	}
+
+}
+
+func contains(elems []string, e string) bool {
+	for _, elem := range elems {
+		if elem == e {
+			return true
+		}
+	}
+	return false
+}
+
 func TestURLPrefix(t *testing.T) {
 	config := configuration.Configuration{
 		Storage: configuration.Storage{
@@ -869,3 +948,60 @@ func checkErr(t *testing.T, err error, msg string) {
 		t.Fatalf("unexpected error %s: %v", msg, err)
 	}
 }
+
+func createRepository(env *testEnv, t *testing.T, imageName string, tag string) {
+	unsignedManifest := &manifest.Manifest{
+		Versioned: manifest.Versioned{
+			SchemaVersion: 1,
+		},
+		Name: imageName,
+		Tag:  tag,
+		FSLayers: []manifest.FSLayer{
+			{
+				BlobSum: "asdf",
+			},
+			{
+				BlobSum: "qwer",
+			},
+		},
+	}
+
+	// Push 2 random layers
+	expectedLayers := make(map[digest.Digest]io.ReadSeeker)
+
+	for i := range unsignedManifest.FSLayers {
+		rs, dgstStr, err := testutil.CreateRandomTarFile()
+
+		if err != nil {
+			t.Fatalf("error creating random layer %d: %v", i, err)
+		}
+		dgst := digest.Digest(dgstStr)
+
+		expectedLayers[dgst] = rs
+		unsignedManifest.FSLayers[i].BlobSum = dgst
+
+		uploadURLBase, _ := startPushLayer(t, env.builder, imageName)
+		pushLayer(t, env.builder, imageName, dgst, uploadURLBase, rs)
+	}
+
+	signedManifest, err := manifest.Sign(unsignedManifest, env.pk)
+	if err != nil {
+		t.Fatalf("unexpected error signing manifest: %v", err)
+	}
+
+	payload, err := signedManifest.Payload()
+	checkErr(t, err, "getting manifest payload")
+
+	dgst, err := digest.FromBytes(payload)
+	checkErr(t, err, "digesting manifest")
+
+	manifestDigestURL, err := env.builder.BuildManifestURL(imageName, dgst.String())
+	checkErr(t, err, "building manifest url")
+
+	resp := putManifest(t, "putting signed manifest", manifestDigestURL, signedManifest)
+	checkResponse(t, "putting signed manifest", resp, http.StatusAccepted)
+	checkHeaders(t, resp, http.Header{
+		"Location":              []string{manifestDigestURL},
+		"Docker-Content-Digest": []string{dgst.String()},
+	})
+}