For operators and developers
Because log-levels should mean the same in all apps
Log-Level Guidelines
In Flowee we have a logging framework which is useful for multiple purposes from developer (debugging) information to fault-finding and general operational monitoring.
Log Levels
The software developer writes code to log events and he has to choose a log-level. Similarly, the operator will choose a log level of which events to actually process.
Software with this line logCritical(Log::RPC) << "event"; will only log
if the operator had selected an appropriate log-level for the RPC
log-section.
| Level | Usage | To show them, use keyword |
|---|---|---|
| debug | Removed from release builds, only for developers | debug |
| info | Generic non-unique event, high-quantity expected | info |
| warning | Similar as info, but for things that went wrong | info |
| critical | High-level events, don’t happen often. Great for understanding what is going on | quiet |
| fatal | Very rare events, can not be silenced | silent |
The guideline for programmers to choose a log level is based on who for and why it is logged. More specific examples:
- Info/warning are events that are for profiling or debugging a node by an operator. So you’ll expect one for each network message, for instance.
- Critical messages are for operators that want to know more about the state of the node or the network. Compare this to a dashboard in a car. A small subsection of useful information is shown here.
- Fatal is typically only used when a component is about to shutdown.
See also logging Sections & Configuration.