Document how hot-code swapping works with agents about xgen HOT 9 CLOSED

Here's an example how it could be done, very easy :/.
https://github.com/fishcakez/agent_telnet/blob/code_change/rel/agent_telnet.appup
https://github.com/fishcakez/agent_telnet/blob/code_change/lib/agent_telnet/supervisor.ex#L9-10
https://github.com/fishcakez/agent_telnet/blob/code_change/lib/agent_telnet/protocol.ex#L34-L36
fishcakez@407255f

from xgen.

very easy :/

Do you mean "very easy :)" or "not very easy :/" ? :P

from xgen.

I mean very easy, :/ because API is not very nice.

On 11 April 2014 19:51, José Valim [email protected] wrote:

very easy :/

Do you mean "very easy :)" or "not very easy :/" ? :P

Reply to this email directly or view it on GitHubhttps://github.com//issues/10#issuecomment-40240610
.

from xgen.

Ah, got it. I still think we should allow a { M, F, A } to be given as state in code change and simply apply that to the state. And starting considering allowing { M, F, A } everywhere else too.

from xgen.

do you mean?

code_change(_vsn, state, { m, f, a }), do: { :ok, Kernel.apply(m, f, [state | a]) }

{update, module, { advanced, { m, f, [a] } }}

That works very nicely!

from xgen.

Yes, exactly!

from xgen.

We just need to work on it and write a test.

from xgen.

This ones free 👍

  test ":sys.change_code/4 with mfa" do
    { :ok, pid } = Agent.start_link(fn -> %{} end)
    :ok = :sys.suspend(pid)
    mfa = { Map, :put, [:hello, :world] }
    assert :sys.change_code(pid, __MODULE__, "vsn", mfa) == :ok
    :ok = :sys.resume(pid)
    assert Agent.get(pid, &Map.get(&1, :hello)) == :world
    assert Agent.stop(pid) == :ok
  end

  test ":sys.change_code/4 with raising mfa" do
    { :ok, pid } = Agent.start_link(fn -> %{} end)
    :ok = :sys.suspend(pid)
    mfa = { :erlang, :error, [] }
    assert match?({ :error, _ }, :sys.change_code(pid, __MODULE__, "vsn", mfa))
    :ok = :sys.resume(pid)
    assert Agent.get(pid, &(&1)) == %{}
    assert Agent.stop(pid) == :ok
  end

from xgen.

The test cases worked like a charm! Thank you! ❤️ 💚 💙 💛 💜

from xgen.