Add tag command for existing local images

pkg/cmd/cmd.go

@@ -88,6 +88,7 @@ func init() {
 			&standbyCmd,
 			&restoreCmd,
 			&forkCmd,
+			&tagCmd,
 			&imageCmd,
 			&ingressCmd,
 			&snapshotCmd,

pkg/cmd/tag.go

@@ -0,0 +1,63 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"os"
+
+	"github.com/kernel/hypeman-go"
+	"github.com/kernel/hypeman-go/option"
+	"github.com/tidwall/gjson"
+	"github.com/urfave/cli/v3"
+)
+
+var tagCmd = cli.Command{
+	Name:            "tag",
+	Usage:           "Tag an existing local image without pulling or converting",
+	ArgsUsage:       "<source> <target>",
+	Action:          handleTag,
+	HideHelpCommand: true,
+}
+
+// tagImageBody is the POST /images/{name}/tag request body, defined locally
+// until the generated SDK gains a typed method for the endpoint.
+type tagImageBody struct {
+	Target string `json:"target"`
+}
+
+func handleTag(ctx context.Context, cmd *cli.Command) error {
+	args := cmd.Args().Slice()
+	if len(args) != 2 {
+		return fmt.Errorf("source and target image references required\nUsage: hypeman tag <source> <target>")
+	}
+	source, target := args[0], args[1]
+
+	client := hypeman.NewClient(getDefaultRequestOptions(cmd)...)
+
+	var opts []option.RequestOption
+	if cmd.Root().Bool("debug") {
+		opts = append(opts, debugMiddlewareOption)
+	}
+
+	var res []byte
+	opts = append(opts, option.WithResponseBodyInto(&res))
+	path := fmt.Sprintf("images/%s/tag", url.PathEscape(source))
+	if err := client.Post(ctx, path, tagImageBody{Target: target}, nil, opts...); err != nil {
+		return err
+	}
+
+	format := cmd.Root().String("format")
+	transform := cmd.Root().String("transform")
+	result := gjson.ParseBytes(res)
+	if format != "auto" {
+		return ShowJSON(os.Stdout, "tag", result, format, transform)
+	}
+
+	imageName := result.Get("name").String()
+	if imageName == "" {
+		imageName = target
+	}
+	fmt.Println(imageName)
+	return nil
+}

pkg/cmd/tag_test.go

@@ -0,0 +1,71 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestTagCommand_RequiresSourceAndTarget(t *testing.T) {
+	err := Command.Run(context.Background(), []string{"hypeman", "tag", "only-source"})
+	require.EqualError(t, err, "source and target image references required\nUsage: hypeman tag <source> <target>")
+}
+
+func TestTagCommand_PostsToTagEndpoint(t *testing.T) {
+	var gotMethod, gotPath string
+	var gotBody []byte
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotMethod = r.Method
+		gotPath = r.URL.EscapedPath()
+		gotBody, _ = io.ReadAll(r.Body)
+		w.Header().Set("Content-Type", "application/json")
+		fmt.Fprint(w, `{"name":"registry.example.com/app:v1","digest":"sha256:abc","status":"ready","created_at":"2026-01-01T00:00:00Z"}`)
+	}))
+	defer srv.Close()
+
+	// Capture os.Stdout: handleTag prints the resolved image name directly.
+	origStdout := os.Stdout
+	r, w, err := os.Pipe()
+	require.NoError(t, err)
+	os.Stdout = w
+
+	runErr := Command.Run(context.Background(), []string{
+		"hypeman", "--base-url", srv.URL,
+		"tag",
+		"docker.io/library/alpine:latest", "registry.example.com/app:v1",
+	})
+
+	w.Close()
+	os.Stdout = origStdout
+	out, readErr := io.ReadAll(r)
+	require.NoError(t, readErr)
+
+	require.NoError(t, runErr)
+	assert.Equal(t, http.MethodPost, gotMethod)
+	assert.Equal(t, "/images/docker.io%2Flibrary%2Falpine:latest/tag", gotPath)
+	assert.JSONEq(t, `{"target":"registry.example.com/app:v1"}`, string(gotBody))
+	assert.Equal(t, "registry.example.com/app:v1\n", string(out))
+}
+
+func TestTagCommand_SurfacesServerError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusNotFound)
+		fmt.Fprint(w, `{"code":"not_found","message":"image not found"}`)
+	}))
+	defer srv.Close()
+
+	err := Command.Run(context.Background(), []string{
+		"hypeman", "--base-url", srv.URL,
+		"tag",
+		"docker.io/library/alpine:missing", "registry.example.com/app:v1",
+	})
+	require.Error(t, err)
+}