ppkarwasz opened a new pull request, #2649: URL: https://github.com/apache/logging-log4j2/pull/2649
Closes #2519. We restructure the pages related to migration between Log4j 1 and Log4j 2 to provide a new "Step by step" guide on migrating between the two major version. The new guide formally introduces the concept of "Log4j 1 API" and provides the user two upgrade paths: 1. If the application or one of its libraries uses Log4j 1 API directly (very unlikely, the usage of Log4j 1 as logging API has declined since the introduction of JCL 22 years ago) the user must apply a set of conversion rules to its source code. We also add a reference to [an OpenRewrite rule](https://docs.openrewrite.org/recipes/java/logging/log4j/log4j1tolog4j2) that does it automatically. 2. If the application uses Log4j 1 as a backend, users can choose a shorter upgrade path that only requires a change in the runtime dependencies. I plan to contribute a separate OpenRewrite recipe for this in #2080 (cf. openrewrite/rewrite-logging-frameworks#154). 3. Conversion of configuration files is treated separately, since there are applications that don't use Log4j 1 any more (neither as logging API or logging backend), but need to provide backward compatibility for their users. The section about "Log4j 1 to Log4j 2 bridge" is splitted among the 3 sections above: 1. Log4j 1 API users only need to add the bridge if they can not modify their source code (or upgrade libraries), 2. Log4j 1 backend users only need to add the bridge if they need to use native Log4j 1 components (and there is no Log4j 2 component that offers the same features), 3. The "Log4j 1 to Log4j 2 bridge" is also required in the rare case, when application developers want to provide BC of configuration files to their users. IIRC Kafka, Hadoop or Spark use this feature. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
