How to handle multiple origins? about cors_plug HOT 4 CLOSED

pry(1)> conn
%Plug.Conn{adapter: {Plug.Adapters.Cowboy.Conn, :...}, assigns: %{},
 before_send: [#Function<1.63666232/1 in Plug.Logger.call/2>,
  #Function<0.63970881/1 in Phoenix.LiveReloader.before_send_inject_reloader/1>],
 body_params: %{}, cookies: %Plug.Conn.Unfetched{aspect: :cookies},
 halted: false, host: "localhost", method: "GET", owner: #PID<0.594.0>,
 params: %{}, path_info: ["books"], peer: {{127, 0, 0, 1}, 54513}, port: 4000,
 private: %{PhoenixGluestickApi.Router => {[], %{GraphQL.Plug.Endpoint => []}},
   :phoenix_action => :index,
   :phoenix_controller => PhoenixGluestickApi.BookController,
   :phoenix_endpoint => PhoenixGluestickApi.Endpoint, :phoenix_format => "json",
   :phoenix_layout => {PhoenixGluestickApi.LayoutView, :app},
   :phoenix_pipelines => [:api],
   :phoenix_route => #Function<7.83685994/1 in PhoenixGluestickApi.Router.match_route/4>,
   :phoenix_router => PhoenixGluestickApi.Router,
   :phoenix_view => PhoenixGluestickApi.BookView,
   :plug_session_fetch => #Function<1.91252167/1 in Plug.Session.fetch_session/1>},
 query_params: %{}, query_string: "", remote_ip: {127, 0, 0, 1},
 req_cookies: %Plug.Conn.Unfetched{aspect: :cookies},
 req_headers: [{"accept", "application/json, text/plain, */*"},
  {"user-agent", "axios/0.9.1"}, {"host", "localhost:4000"},
  {"connection", "close"}], request_path: "/books", resp_body: nil,
 resp_cookies: %{},
 resp_headers: [{"cache-control", "max-age=0, private, must-revalidate"},
  {"x-request-id", "o62r797gj82usvpdkc7pt66hgutf9635"},
  {"access-control-allow-origin", nil}, {"access-control-expose-headers", ""},
  {"access-control-allow-credentials", "true"}], scheme: :http, script_name: [],
 secret_key_base: "/VuSjVh9ADlr+UPsWvmCTLixXdp3FUsavpVD+Jy6pYrOqVrBQePClJ6frP5d0G4K",
 state: :unset, status: nil}
pry(2)> respawn

Interactive Elixir (1.2.0) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> [info] Sent 200 in 7200ms
iex(1)> [error] Bad value on output port 'tcp_inet'