How to set environments and workdir and save these to the exported image with moby/buildkit?

[niclausse]

My demo codes are as below. I use 'state.WithImageConfig()' to set the metadata, but it doesn't work in the exported image!

	ic, _ := json.Marshal(ocispecs.Image{
		Platform: *platform,
		Config: ocispecs.ImageConfig{
			Env:        convertEnv(opt.ENV),
			WorkingDir: opt.Workdir,
		},
	})

	curr, err = curr.WithImageConfig(ic)
	if err != nil {
		return err
	}

	// Trigger application of image config
	curr = curr.Run(
		llb.Shlex("env"),
		llb.WithCustomName("******Print Env*******"),
	).Root()

	def, err := curr.Marshal(ctx, llb.Platform(*platform))
         	if err != nil {
		return errors.Wrap(err, "failed to marshal final LLB state to definition")
	}

	// 准备 context 资源
	fs, err := fsutil.NewFS(opt.BuildContext)
	if err != nil {
		return errors.Wrap(err, "failed to create build context fs")
	}

	display, err := progressui.NewDisplay(os.Stdout, progressui.PlainMode)
	if err != nil {
		return fmt.Errorf("create display failed: %w", err)
	}

	ch := make(chan *client.SolveStatus)
	go func() {
		_, err = display.UpdateFrom(ctx, ch)
		if err != nil {
			log.Printf("progress display error: %v", err)
		}
	}()

	// 执行构建
	_, err = bkClient.Solve(ctx, def, client.SolveOpt{
		Exports: []client.ExportEntry{
			{
				Type: client.ExporterImage,
				Attrs: map[string]string{
					"name": opt.TargetImage,
					"push": "true",
				},
			},
		},
		Session: []session.Attachable{
			authprovider.NewDockerAuthProvider(authprovider.DockerAuthProviderConfig{
				ConfigFile: kit.configFile,
			}),
		},
		LocalMounts: map[string]fsutil.FS{
			"context": fs,
		},
	}, ch)
	if err != nil {
		return fmt.Errorf("构建失败: %w", err)
	}