For many applications, logging is written to a rolling log file or the Windows Event Log. In a cloud application, this becomes an anti-pattern because you need to either depend on a distributed logging system, or a platform feature. To move away from these dependencies, the 12 factor application methodology recomends outputting logs as a stream to stdout/stderror.

When migrating a legacy application, we often recomend configuring any existing logging framework to output to stdout/stderror. Each recipe in this section documents a set of steps that were taken when working with a 3rd party logging framework.