feat: Support for GitHub Container Registry (ghcr.io) (#96)

* feat: Support for GitHub Container Registry (ghcr.io)

* We now have 5 default registries instead of 4

* Add ghcr to allowed words for spelling

4 files changed, 26 insertions, 9 deletions

diff --git a/.github/actions/spelling/allow.txt b/.github/actions/spelling/allow.txt
index a8ac238..587e4c4 100644
--- a/.github/actions/spelling/allow.txt
+++ b/.github/actions/spelling/allow.txt
@@ -60,6 +60,7 @@ func
 gcr
 Getenv
 gh
+ghcr
 githash
 github
 goimports
diff --git a/docs/configuration/registries.md b/docs/configuration/registries.md
index e783355..70ebde9 100644
--- a/docs/configuration/registries.md
+++ b/docs/configuration/registries.md
@@ -4,9 +4,10 @@ Argo CD Image Updater comes with support for the following registries out of the
 box:
 
 * Docker Hub Registry
-* Google Container Registry
-* RedHat Quay Registry
-* GitHub Docker Registry
+* Google Container Registry (*gcr.io*)
+* RedHat Quay Registry (*quay.io*)
+* GitHub Docker Packages (*docker.pkg.github.com*)
+* GitHub Container Registry (*ghcr.io*)
 
 Adding additional (and custom) container registries is supported by means of a
 configuration file. If you run Argo CD Image Updater within Kubernetes, you can
@@ -36,10 +37,16 @@ registries:
   prefix: quay.io
   insecure: yes
   credentials: env:REGISTRY_SECRET
+- name: GitHub Docker Packages
+  prefix: docker.pkg.github.com
+  api_url: https://docker.pkg.github.com
+  ping: no
+  tagsortmode: latest-first
 - name: GitHub Container Registry
+  prefix: ghcr.io
   api_url: https://docker.pkg.github.com
   ping: no
-  tagsortmode: latest_first
+  tagsortmode: latest-last
 ```
 
 The above example defines access to three registries. The properties have the
@@ -70,10 +77,10 @@ following semantics:
   `library/nginx:latest`.
 
 * `tagsortmode` (optional) defines whether and how the list of tags is sorted
-  chronologically by the registry. Valid values are `latest_first` (the last
-  pushed image will appear first in list), `latest_last` (the last pushed image
+  chronologically by the registry. Valid values are `latest-first` (the last
+  pushed image will appear first in list), `latest-last` (the last pushed image
   will appear last in list) or `none` (the default, list is not chronological
-  sorted). If `tagsortmode` is set to one of `latest_first` or `latest_last`,
+  sorted). If `tagsortmode` is set to one of `latest-first` or `latest-last`,
   Argo CD Image Updater will not request additional meta data from the registry
   if the `<image_alias>.sort-mode` is `latest` but will instead use the sorting
   from the tag list.
diff --git a/pkg/registry/config_test.go b/pkg/registry/config_test.go
index 29e6cfb..2d7ac26 100644
--- a/pkg/registry/config_test.go
+++ b/pkg/registry/config_test.go
@@ -77,7 +77,7 @@ func Test_LoadRegistryConfiguration(t *testing.T) {
 	t.Run("Load from valid location", func(t *testing.T) {
 		err := LoadRegistryConfiguration("../../config/example-config.yaml", false)
 		require.NoError(t, err)
-		assert.Len(t, registries, 4)
+		assert.Len(t, registries, 5)
 		reg, err := GetRegistryEndpoint("gcr.io")
 		require.NoError(t, err)
 		assert.Equal(t, "pullsecret:foo/bar", reg.Credentials)
diff --git a/pkg/registry/endpoints.go b/pkg/registry/endpoints.go
index e2e726b..9058ba2 100644
--- a/pkg/registry/endpoints.go
+++ b/pkg/registry/endpoints.go
@@ -84,7 +84,7 @@ var defaultRegistries map[string]*RegistryEndpoint = map[string]*RegistryEndpoin
 		Cache:          cache.NewMemCache(),
 	},
 	"docker.pkg.github.com": {
-		RegistryName:   "GitHub registry",
+		RegistryName:   "GitHub packages",
 		RegistryPrefix: "docker.pkg.github.com",
 		RegistryAPI:    "https://docker.pkg.github.com",
 		Ping:           false,
@@ -92,6 +92,15 @@ var defaultRegistries map[string]*RegistryEndpoint = map[string]*RegistryEndpoin
 		TagListSort:    SortLatestFirst,
 		Cache:          cache.NewMemCache(),
 	},
+	"ghcr.io": {
+		RegistryName:   "GitHub Container Registry",
+		RegistryPrefix: "ghcr.io",
+		RegistryAPI:    "https://ghcr.io",
+		Ping:           false,
+		Insecure:       false,
+		TagListSort:    SortLatestLast,
+		Cache:          cache.NewMemCache(),
+	},
 }
 
 var registries map[string]*RegistryEndpoint = make(map[string]*RegistryEndpoint)