From 722a143ce9dc8c1604ff388d2ed94c38f6d9f0c1 Mon Sep 17 00:00:00 2001
From: Carlos Panato <ctadeu@gmail.com>
Date: Mon, 22 Feb 2021 14:45:23 +0100
Subject: [PATCH] implement catalog tests

Signed-off-by: Carlos Panato <ctadeu@gmail.com>
---
 pkg/crane/crane_test.go       | 15 +++++++++-
 pkg/registry/manifest.go      | 56 +++++++++++++++++++++++++++++++++++
 pkg/registry/registry.go      |  3 ++
 pkg/registry/registry_test.go |  7 +++++
 4 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/pkg/crane/crane_test.go b/pkg/crane/crane_test.go
index 5e402c19cd..80a257af73 100644
--- a/pkg/crane/crane_test.go
+++ b/pkg/crane/crane_test.go
@@ -34,7 +34,6 @@ import (
 	"github.com/google/go-containerregistry/pkg/v1/remote"
 )
 
-// TODO(jonjohnsonjr): Test crane.Catalog behavior.
 // TODO(jonjohnsonjr): Test crane.Copy failures.
 func TestCraneRegistry(t *testing.T) {
 	// Set up a fake registry.
@@ -195,6 +194,20 @@ func TestCraneRegistry(t *testing.T) {
 	if err := compare.Images(dstPulled, copied); err != nil {
 		t.Fatal(err)
 	}
+
+	// List Catalog
+	repos, err := crane.Catalog(u.Host)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(repos) != 2 {
+		t.Fatalf("wanted 2 repos, got %d", len(repos))
+	}
+
+	_, err = crane.Catalog("registry.honk")
+	if err == nil {
+		t.Fatal("should error, registry does not exist")
+	}
 }
 
 func TestCraneCopyIndex(t *testing.T) {
diff --git a/pkg/registry/manifest.go b/pkg/registry/manifest.go
index 5dc920abb7..cf58724444 100644
--- a/pkg/registry/manifest.go
+++ b/pkg/registry/manifest.go
@@ -31,6 +31,10 @@ import (
 	"github.com/google/go-containerregistry/pkg/v1/types"
 )
 
+type catalog struct {
+	Repos []string `json:"repositories"`
+}
+
 type listTags struct {
 	Name string   `json:"name"`
 	Tags []string `json:"tags"`
@@ -65,6 +69,16 @@ func isTags(req *http.Request) bool {
 	return elems[len(elems)-2] == "tags"
 }
 
+func isCatalog(req *http.Request) bool {
+	elems := strings.Split(req.URL.Path, "/")
+	elems = elems[1:]
+	if len(elems) < 2 {
+		return false
+	}
+
+	return elems[len(elems)-1] == "_catalog"
+}
+
 // https://github.com/opencontainers/distribution-spec/blob/master/spec.md#pulling-an-image-manifest
 // https://github.com/opencontainers/distribution-spec/blob/master/spec.md#pushing-an-image
 func (m *manifests) handle(resp http.ResponseWriter, req *http.Request) *regError {
@@ -273,3 +287,45 @@ func (m *manifests) handleTags(resp http.ResponseWriter, req *http.Request) *reg
 		Message: "We don't understand your method + url",
 	}
 }
+
+func (m *manifests) handleCatalog(resp http.ResponseWriter, req *http.Request) *regError {
+	query := req.URL.Query()
+	nStr := query.Get("n")
+	n := 10000
+	if nStr != "" {
+		n, _ = strconv.Atoi(nStr)
+	}
+
+	if req.Method == "GET" {
+		m.lock.Lock()
+		defer m.lock.Unlock()
+
+		var repos []string
+		countRepos := 0
+		// TODO: implement pagination
+		for key := range m.manifests {
+			if countRepos >= n {
+				break
+			}
+			countRepos++
+
+			repos = append(repos, key)
+		}
+
+		repositoriesToList := catalog{
+			Repos: repos,
+		}
+
+		msg, _ := json.Marshal(repositoriesToList)
+		resp.Header().Set("Content-Length", fmt.Sprint(len(msg)))
+		resp.WriteHeader(http.StatusOK)
+		io.Copy(resp, bytes.NewReader([]byte(msg)))
+		return nil
+	}
+
+	return &regError{
+		Status:  http.StatusBadRequest,
+		Code:    "METHOD_UNKNOWN",
+		Message: "We don't understand your method + url",
+	}
+}
diff --git a/pkg/registry/registry.go b/pkg/registry/registry.go
index 8e92bfb2c5..f28f219a75 100644
--- a/pkg/registry/registry.go
+++ b/pkg/registry/registry.go
@@ -47,6 +47,9 @@ func (r *registry) v2(resp http.ResponseWriter, req *http.Request) *regError {
 	if isTags(req) {
 		return r.manifests.handleTags(resp, req)
 	}
+	if isCatalog(req) {
+		return r.manifests.handleCatalog(resp, req)
+	}
 	resp.Header().Set("Docker-Distribution-API-Version", "registry/2.0")
 	if req.URL.Path != "/v2/" && req.URL.Path != "/v2" {
 		return &regError{
diff --git a/pkg/registry/registry_test.go b/pkg/registry/registry_test.go
index debf0117b3..af9a384db3 100644
--- a/pkg/registry/registry_test.go
+++ b/pkg/registry/registry_test.go
@@ -390,6 +390,13 @@ func TestCalls(t *testing.T) {
 			URL:         "/v2/foo/tags/list?n=1000",
 			Code:        http.StatusNotFound,
 		},
+		{
+			Description: "list repos",
+			Manifests:   map[string]string{"foo/manifests/latest": "foo", "bar/manifests/latest": "bar"},
+			Method:      "GET",
+			URL:         "/v2/_catalog?n=1000",
+			Code:        http.StatusOK,
+		},
 	}
 
 	for _, tc := range tcs {