Creating a sub_log does not respect the initial log level

[Flemming Madsen]

Given the folllowing code:

let my_log = Dream.sub_log ~level:`Error "my.log"

let () =
  Dream.run
  @@ Dream.logger
  @@ Dream.router
       [ Dream.get "/" (fun _ -> Dream.html "Welcome to my website")
       ; Dream.get "/echo/:word" (fun req ->
           my_log.warning (fun log -> log ~request:req "echo path");
           Dream.html (Printf.sprintf "Hello, %s" @@ Dream.param req "word"))
       ]
;;

I expect that echo path will not be logged, as it is a warning, and this sub_log is only configured with errors.

However, it is still being logged:

15.09.23 10:00:58.532       dream.log  INFO REQ 1 GET /echo/dream 127.0.0.1:45198 Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/51
15.09.23 10:00:58.532          my.log  WARN REQ 1 echo path
15.09.23 10:00:58.532       dream.log  INFO REQ 1 200 in 87 μs

"Manually" setting the log level with the following line:

let () = Dream.set_log_level "my.log" `Error

Makes it behave as expected:

15.09.23 10:03:37.447       dream.log  INFO REQ 1 GET /echo/dream 127.0.0.1:33510 Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/51
15.09.23 10:03:37.447       dream.log  INFO REQ 1 200 in 56 μs

I am running OCaml 4.14.1 under WSL2

[Anton Bachin]

Thank you! This has been fixed in the linked commit and will be out in the next release.

The whole logging initialization code could probably use a rework, as it was already complex when only trying to integrate with Logs, but it is now even more complex because of Mirage support, and it's difficult to follow.