Add logging standards to go guidelines

The following discussion from !24661 (merged) should be addressed:

• @steveazz started a discussion: (+2 comments)

  Should we define somewhere here that we prefer structured logging specifically JSON structured logging since all our infra expects it?

@steveazz do you have examples to share? I will add a new section to address this. Thanks

added development guidelines documentation golang labels

@plafoucriere what kind of examples are you looking for? On how to use logrus?

I think if we do the following it would be good:

1. Linking to https://docs.gitlab.com/ee/development/logging.html#use-structured-json-logging and specify we want to reflect this in our Go code as well
2. Specify to use logrus json default formatter.
3. Every time we log an error use the .WithError field instead of formatting yourself.
4. Suggest using .WithFields to print out specific values.

WDYT? I think later on we should discuss what kind of fields we should print for every log. For example, always logging the build name/tag to increased observability.

Exactly what I was looking for, thanks! I will create a MR accordingly (unless you want to do it yourself).

@plafoucriere I can do it myself if that is ok with you and then assign it to you when done

That would be great. Thank you!

mentioned in commit 3828b545

mentioned in merge request !25713 (closed)

mentioned in merge request !25714 (merged)

mentioned in commit fa247d60

mentioned in commit 60207471

mentioned in commit 5665ecee

closed via merge request !25714 (merged)

mentioned in commit 250f6ad2