...
- Field separator reverted to pipe.
- Dual appenders in Logback and Log4j reference configurations:
- Indexable, for shipping and indexing.
- EELF, for backward compatibility.
- Minor changes to path conventions.
- XML output deprecated (required only for Log4j1.2, which is also expected to go).
- Improved documentation of semantics and usage (including initialization and propagation via ThreadLocal and HTTP headers) for existing MDCs and attributes.
- Add MDCs/Markers + usage for invocation IDs, allowing call graphs to be built without reliance on heuristics.
- Revisiting persistence (a clear requirement) and rollover settings, based on feedback from operations.
- More discussion of How to Log. (Where previously guidelines were largely concerned with architecture and mechanics).
- Locking in other changes proposed in R1, including MDC serialization, escaping, etc. These can be treated as accepted. (Note that they only affect indexable output).
In addition, we expect to provide (as a Beijing deliverable) a minimal, synthetic component as an example of best-practices, and this will provide all code examples for this guide. (Does that mean the example will log via EELF, or will we end up with two variants?)