...

• Events that are written by ONAP components.
• Propagation of transaction and invocation information between components.
• MDCs, Markers and other information that should be attached to log messages.
  • MDC = Mapped Diagnostic Context
• Human and machine-readable output format(s).
• Files, locations and other conventions. 

Java and Python are supported, but conventions may be implemented by other technologies like GO.   

Original AT&T ONAP Logging guidelines (pre amsterdam release) - for historical reference only: https://wiki.onap.org/download/attachments/1015849/ONAP%20application%20logging%20guidelines.pdf?api=v2

...

This document proposes conventions you can follow to generate conformant, indexable logging output from your component.

Supported Languages

Java (including Scala and Clojure - because they compile to the same bytecode) and Python are supported, but conventions may be implemented by other technologies like GO. 

Java

The library and aop wrapper are written in Java and will work for Clojure (thanks to a discussion with Shwetank Dave that reminded my of languages that compile to bytecode) and Scala as well. see: https://git.onap.org/logging-analytics/tree/reference

Clojure

See the java libraries

Scala

see the java libraries

Python

How to Log

ONAP prescribes conventions. The use of certain APIs and providers is recommended, but they are not mandatory. Most components log via EELF or SLF4J to a provider like Logback or Log4j.

...