Document --log argument

[h4x3rotab]

The format of the --log argument is unclear now. It only says:

Sets a custom logging filter. Syntax is <target>=<level>, e.g. -lsync=debug.

Log levels (least to most verbose) are error, warn, info, debug, and trace. By default, all targets log info. The global log level can be set with -l<level>.

However the format can be very flexible. E.g. it supports setting log levels for multiple component: info,lsync=debug. Does it follow the env_logger's standard described here?

If so, I think it's necessary to make it explicitly described in the command line flag docs.

[dvdplm]

Does it follow the env_logger's standard described here?

Yes, it does. And I agree it would be good to mention the docs you link to. Do you mind opening a PR for that? :)

[qdm12]

Related question, it mentions

substrate/client/cli/src/params/shared_params.rs

Line 48 in 0e0cdd8

/// By default, all targets log `info`. The global log level can be set with -l<level>.

Is there any documentation or variable defining all the possible targets? Thanks!!

[bkchr]

No there is no documentation on all the possible levels. I would also not recommend to copy this over to gossamer. Just come up with your own logging targets. In rust logging targets are for example the crate names if there is no explicit target given.