feat: support login

go.mod

@@ -8,6 +8,8 @@ require (
 )
 
 require (
+	github.com/opencontainers/go-digest v1.0.0 // indirect
+	github.com/opencontainers/image-spec v1.1.0-rc2 // indirect
 	golang.org/x/sync v0.1.0 // indirect
 	golang.org/x/sys v0.6.0 // indirect
 )

go.sum

@@ -1,5 +1,9 @@
 github.com/docker/docker-credential-helpers v0.7.0 h1:xtCHsjxogADNZcdv1pKUHXryefjlVRqWqIhk/uXJp0A=
 github.com/docker/docker-credential-helpers v0.7.0/go.mod h1:rETQfLdHNT3foU5kuNkFR1R1V12OJRRO5lzt2D1b5X0=
+github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8Oi/yOhh5U=
+github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
+github.com/opencontainers/image-spec v1.1.0-rc2 h1:2zx/Stx4Wc5pIPDvIxHXvXtQFW/7XWJGmnM7r3wg034=
+github.com/opencontainers/image-spec v1.1.0-rc2/go.mod h1:3OVijpioIKYWTqjiG0zfF6wvoJ4fAXGbjdZuI2NgsRQ=
 golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=

login.go

@@ -0,0 +1,36 @@
+/*
+Copyright The ORAS Authors.
+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 credentials
+
+import (
+	"context"
+	"fmt"
+
+	"oras.land/oras-go/v2/registry/remote"
+	"oras.land/oras-go/v2/registry/remote/auth"
+)
+
+// Login provides the login functionality with the given credentials.
+func Login(ctx context.Context, store Store, registry remote.Registry, cred auth.Credential) error {
+	if err := registry.Ping(ctx); err != nil {
+		return fmt.Errorf("unable to connect to the registry: %v", err)
+	}
+	if err := store.Put(ctx, registry.Reference.Registry, cred); err != nil {
+		return fmt.Errorf("unable to store the credential: %v", err)
+	}
+	fmt.Println("Login Succeeded")
+	return nil
+}

login_test.go

@@ -0,0 +1,89 @@
+/*
+Copyright The ORAS Authors.
+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 credentials
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+
+	"oras.land/oras-go/v2/registry/remote"
+	"oras.land/oras-go/v2/registry/remote/auth"
+)
+
+// testStore implements the Store interface, used for testing purpose.
+type testStore struct{}
+
+func (t *testStore) Get(ctx context.Context, serverAddress string) (auth.Credential, error) {
+	return auth.Credential{}, nil
+}
+
+func (t *testStore) Put(ctx context.Context, serverAddress string, cred auth.Credential) error {
+	return nil
+}
+
+func (t *testStore) Delete(ctx context.Context, serverAddress string) error {
+	return nil
+}
+
+func TestLogin(t *testing.T) {
+	// create a test registry
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {}))
+	defer ts.Close()
+	uri, _ := url.Parse(ts.URL)
+	reg, err := remote.NewRegistry(uri.Host)
+	if err != nil {
+		panic("cannot create test registry")
+	}
+	reg.PlainHTTP = true
+
+	// create a test store
+	ns := &testStore{}
+	tests := []struct {
+		name     string
+		ctx      context.Context
+		store    Store
+		registry remote.Registry
+		cred     auth.Credential
+		wantErr  bool
+	}{
+		{
+			name:     "login succeeds",
+			ctx:      context.Background(),
+			store:    ns,
+			registry: *reg,
+			cred:     auth.Credential{Username: testUsername, Password: testPassword},
+			wantErr:  false,
+		},
+		{
+			name:     "login fails (nil context makes remote.Ping fails)",
+			ctx:      nil,
+			store:    ns,
+			registry: *reg,
+			cred:     auth.Credential{Username: testUsername, Password: testPassword},
+			wantErr:  true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := Login(tt.ctx, tt.store, tt.registry, tt.cred); (err != nil) != tt.wantErr {
+				t.Errorf("Login() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}

native_store.go

@@ -42,7 +42,7 @@ func NewNativeStore(helperSuffix string) Store {
 	}
 }
 
-// Get retrieves credentials from the store for the given server
+// Get retrieves credentials from the store for the given server.
 func (ns *NativeStore) Get(_ context.Context, serverAddress string) (auth.Credential, error) {
 	var cred auth.Credential
 	dockerCred, err := client.Get(ns.programFunc, serverAddress)
@@ -63,7 +63,7 @@ func (ns *NativeStore) Get(_ context.Context, serverAddress string) (auth.Creden
 	return cred, nil
 }
 
-// Put saves credentials into the store
+// Put saves credentials into the store.
 func (ns *NativeStore) Put(_ context.Context, serverAddress string, cred auth.Credential) error {
 	dockerCred := &credentials.Credentials{
 		ServerURL: serverAddress,
@@ -77,7 +77,7 @@ func (ns *NativeStore) Put(_ context.Context, serverAddress string, cred auth.Cr
 	return client.Store(ns.programFunc, dockerCred)
 }
 
-// Delete removes credentials from the store for the given server
+// Delete removes credentials from the store for the given server.
 func (ns *NativeStore) Delete(_ context.Context, serverAddress string) error {
 	return client.Erase(ns.programFunc, serverAddress)
 }