adds support for the /v2/_catalog API

pkg/v1/remote/catalog.go

@@ -0,0 +1,70 @@
+// Copyright 2018 Google LLC All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package remote
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"github.com/google/go-containerregistry/pkg/name"
+	"github.com/google/go-containerregistry/pkg/v1/remote/transport"
+)
+
+type catalog struct {
+	Repos []string `json:"repositories"`
+}
+
+// GetCatalog calls /_catalog, returning the list of repositories on the registry
+func GetCatalog(target name.Registry, last string, n int, options ...Option) ([]string, error) {
+	o, err := makeOptions(target, options...)
+	if err != nil {
+		return nil, err
+	}
+
+	scopes := []string{target.Scope(transport.PullScope)}
+	tr, err := transport.New(target, o.auth, o.transport, scopes)
+	if err != nil {
+		return nil, err
+	}
+
+	query := fmt.Sprintf("last=%s&n=%d", url.QueryEscape(last), n)
+
+	uri := url.URL{
+		Scheme:   target.Scheme(),
+		Host:     target.RegistryStr(),
+		Path:     "/v2/_catalog",
+		RawQuery: query,
+	}
+
+	client := http.Client{Transport: tr}
+	resp, err := client.Get(uri.String())
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if err := transport.CheckError(resp, http.StatusOK); err != nil {
+		return nil, err
+	}
+
+	var parsed catalog
+	if err := json.NewDecoder(resp.Body).Decode(&parsed); err != nil {
+		return nil, err
+	}
+
+	return parsed.Repos, nil
+}

pkg/v1/remote/catalog_test.go

@@ -0,0 +1,84 @@
+// Copyright 2018 Google LLC All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package remote
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-containerregistry/pkg/authn"
+	"github.com/google/go-containerregistry/pkg/name"
+)
+
+func TestGetCatalog(t *testing.T) {
+	cases := []struct {
+		name         string
+		responseBody []byte
+		wantErr      bool
+		wantRepos    []string
+	}{{
+		name:         "success",
+		responseBody: []byte(`{"repositories":["test/test","foo/bar"]}`),
+		wantErr:      false,
+		wantRepos:    []string{"test/test", "foo/bar"},
+	}, {
+		name:         "not json",
+		responseBody: []byte("notjson"),
+		wantErr:      true,
+	}}
+	//TODO: add test cases for pagination
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			catalogPath := "/v2/_catalog"
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				switch r.URL.Path {
+				case "/v2/":
+					w.WriteHeader(http.StatusOK)
+				case catalogPath:
+					if r.Method != http.MethodGet {
+						t.Errorf("Method; got %v, want %v", r.Method, http.MethodGet)
+					}
+
+					w.Write(tc.responseBody)
+				default:
+					t.Fatalf("Unexpected path: %v", r.URL.Path)
+				}
+			}))
+			defer server.Close()
+			u, err := url.Parse(server.URL)
+			if err != nil {
+				t.Fatalf("url.Parse(%v) = %v", server.URL, err)
+			}
+
+			reg, err := name.NewRegistry(u.Host)
+			if err != nil {
+				t.Fatalf("name.NewRegistry(%v) = %v", u.Host, err)
+			}
+
+			repos, err := GetCatalog(reg, "", 100, WithAuthFromKeychain(authn.DefaultKeychain))
+			if (err != nil) != tc.wantErr {
+				t.Errorf("GetCatalog() wrong error: %v, want %v: %v\n", (err != nil), tc.wantErr, err)
+			}
+
+			if diff := cmp.Diff(tc.wantRepos, repos); diff != "" {
+				t.Errorf("GetCatalog() wrong repos (-want +got) = %s", diff)
+			}
+		})
+	}
+}