How to get client iP address in elixir logger

Questions & Help Questions
1

Using elixir, I am trying to get client ip address in logger, but not able to get that. Any kind of help will be appreciated.

2

Hello and welcome to the forum, It is not mentionned if You use Phoenix, but if yes, then You can get remote_ip from conn.

See https://hexdocs.pm/plug/Plug.Conn.html

3

Thanks for your help. I’m using Phoenix. I’ll try your suggestion.

4

I added remote IP address to logs of a Phoenix app. Sharing a code snippet here for my future self and the rest of the community:

# lib/my_app_web/endpoint.ex
defmodule MyAppWeb.Endpoint do
  use Phoenix.Endpoint, otp_app: :my_app

  # ...
  plug Plug.RequestId
  plug :logger_metadata_remote_ip
  # ...

  defp logger_metadata_remote_ip(conn, _) do
    Logger.metadata(remote_ip: List.to_string(:inet.ntoa(conn.remote_ip)))
    conn
  end
end

# config/config.exs
config :logger, :default_formatter,
  format: "$time $metadata[$level] $message\n",
  metadata: [:request_id, :remote_ip]

Note that IP addresses are generally treated as personal data under GDPR (and similar regimes), so treat them with appropriate care and consider anonymization.

5

You likely want to also use remote_ip | Hex as most apps are deployed behind reverse proxy of some kind

6

Good call. That will vary case by case, though.

There’s also Plug.RewriteOn and the :force_ssl Endpoint config in Phoenix (that uses Plug.SSL under the hood and also rewrites conn fields), so one may also get around without yet another dependency.