Why does Logger output in IEX have to have an empty line after every line logged?

chanon · April 22, 2019, 9:32am

This is a capture of iex running my test app. The Logger.debug output statements all have an empty line after them. Is there a way to fix this? It reduces the amount of log lines I can see on a screen by half.

voltone · April 22, 2019, 9:35am

If we’re talking about a Phoenix app, you’ll probably find a line like this in your config: config :logger, :console, format: "[$level] $message\n"

If this is a blank Elixir app, you can add such a line to your config. You can tune the format as you wish.

chanon · April 22, 2019, 9:54am

Thanks!

It isn’t a Phoenix app.
But I found the default Logger format is actually:
config :logger, :console, format: "\n$time $metadata[$level] $levelpad$message\n"

from:

github.com

elixir-lang/elixir/blob/459319fb751f81399b6e3826789782452ea5c3c9/lib/logger/lib/logger.ex#L239


### Console backend


The console backend logs messages by printing them to the console. It supports
the following options:


  * `:level` - the level to be logged by this backend.
    Note that messages are filtered by the general
    `:level` configuration for the `:logger` application first.


  * `:format` - the format message used to print logs.
    Defaults to: `"\n$time $metadata[$level] $levelpad$message\n"`.
    It may also be a `{module, function}` tuple that is invoked
    with the log level, the message, the current timestamp and
    the metadata.


  * `:metadata` - the metadata to be printed by `$metadata`.
    Defaults to an empty list (no metadata).
    Setting `:metadata` to `:all` prints all metadata. See
    the "Metadata" section for more information.


  * `:colors` - a keyword list of coloring options.

So I can just copy it and remove the \n in front.

kitplummer · March 24, 2020, 2:30pm

I can’t for the life of me get this to work, to actually fix the logging output. I can’t be the only one. I’m on Elixir 1.10.2.

1player · March 24, 2020, 2:33pm

Change:

config :logger, :console, format: "\n$time $metadata[$level] $levelpad$message\n"

into:

config :logger, :console, format: "$time $metadata[$level] $levelpad$message\n"

in your config.exs file.

kitplummer · March 24, 2020, 2:35pm

Yep, did that. It isn’t changing the format. I know my config setup is fine, as other items are getting set.

kombainer · May 1, 2023, 8:43am

1player Thanks a lot.