Terminal coloration

[Nemikolh]

Hello there!

I have realised log4rs does not provide terminal coloration by default. Would you be interested in the feature?

For comparison, loggers such as log4js and winston provides terminal coloration by default.

If you like the idea but don't have the time for it, I would gladly work on it. :)

[sfackler]

Yep, definitely seems reasonable to implement! I will probably not have a ton of time to work on it, but if you were willing to that'd be great.

[ryantaylor]

I really like this library but I needed colorization, so I went ahead and hacked in super basic, super dirty functionality. No config or anything, just hard-coded colour values for different log levels. I wrote it for my own use until someone smarter than me found the time to implement a proper solution, but I figured I'd post it here in case it helps. If nobody else finds the time to work on this functionality I might look into cleaning up the code and doing it right.

ryantaylor@4ded253

[Nemikolh]

To be fair, I haven't found much time to work on this. Thanks for working on it !

As a comparison this is the default in log4js:

With your solution, it currently looks like this:

In my opinion, this is already a big improvement !
If you're willing to write a cleaner solution for it, feel free to do so.

[nicokoch]

Is anyone still working on this? If not, I am willing to pick it up.

I will need some pointers on how one would configure this in the .toml file

[sfackler]

I don't think anyone's working on it right now. Logback's pattern syntax might be a place to look for configuration syntax inspiration: http://logback.qos.ch/manual/layouts.html#coloring

[sfackler]

I've started working on this.

[sfackler]

Progress! The encoder::Write trait has been extended with a set_style method, which can control the foreground and background colors as well as the foreground intensity of text it outputs. The console appender now colors text if attached to a tty/console. I've also added a new "highlight" formatter to the pattern syntax, which sets the color based on the log level. For example, the test crate now has the pattern {d} [{t}] {h({l})} {M}:{m}{n}, which produces output that looks like this when it runs:

I copied the color selections from logback: intense red for error, red for warning, blue for info, and default for everything else.

I'd like to add a pattern formatter or group of them that lets you pick a specific style, but I'm not sure about the syntax right now.

[sfackler]

I've released v0.4.3 with color support. All that the pattern encoder supports right now is level-based styling. I've opened a new issue to figure out syntax for configuration of specific styles: #17

[ivnsch]

Hi! I started using log4s and not seeing any colors in the terminal (I see them e.g. with pretty_env_logger). Do I have to enable it somewhere?

[estk]

see #204 , its in progress but seems to be stalled

[OvermindDL1]

What's keeping it stalled currently?

[Creative-Difficulty]

Is there any progress at all @estk ?

[Pr0gm4n]

@Creative-Difficulty you may want to try using the formatter {h} documented in the log4rs::encode::pattern, i.e., here.

As an example, you could use this in your yaml_config:

appenders:
  # An appender named "stdout" that writes to stdout
  stdout:
    kind: console
    target: stdout
    encoder:
      pattern: " {h({l:<5}} {M} > {m}{n}"

# Set the default logging level to "warn" and attach the "stdout" appender to the root
root:
  level: info
  appenders:
    - stdout

This should look somewhat similar to the output produced by the pretty_env_logger crate, although not with its neat alignment.