Log levels

Levels describe the significance of a log event in a coarse-grained way that's easy to organize and filter on. emit doesn't bake in the concept of log levels directly, but supports them through the lvl well-known property. emit defines four well-known levels; a strong and a weak variant of informative and erroneous events:

• "debug": for events supporting live debugging. These events are likely to be filtered out, or only retained for a short period.
• "info": for most events. These events are the core diagnostics of your applications that give you a good picture of what's happening.
• "warn": for recoverable or non-esential erroneous events. They may help explain some unexpected behavior or point to issues to investigate.
• "error": for erroneous events that cause degraded behavior and need to be investigated.

When emitting events, you can use a macro corresponding to a given level to have it attached automatically:

• debug!
• info!
• warn!
• error!

emit's levels are intentionally very coarse-grained and aren't intended to be extended. You can define your own levelling scheme in your applications if you want.