Log4j 2 module deprecation

[vy]

[This message is cross-post of a mailing list thread. Depending on your preference, you can participate either here or there.]

We always strive to only release industrial-strength components.

Following an internal discussion and looking at statistics from several sources, the PMC plans to deprecate in the 2.x version several components for removal in 3.x.

We know that statistics are not everything and that is why 📢 we would like to hear your opinion on these modules. The discussion will be open for a month, after which the PMC will announce a definitive list of deprecations.

Cassandra appender (log4j-cassandra)

We support Cassandra 3.x, which will reach end-of-life when 4.2.x is released. Since the stats show marginal usage of the module, we expect neither a log4j-cassandra4.

CouchDB appender (log4j-couchdb)

It is even less used than Cassandra according to the stats.

Docker lookup (log4j-docker)

Seldom used and standard practice is generally to log to the console and let the Docker environment add the data.

GELF layout (GelfLayout in log4j-core)

It is mostly superseded by the JSON Template Layout.

Kafka appender (KafkaAppender in log4j-core)

It contains several critical bug reports neither the PMC, nor the community is willing to deal with.

Kubernetes lookup (log4j-kubernetes)

Seldom used and standard practice is generally to log to the
console and let the Docker environment add the data.

ZeroMQ appender (JeroMqAppender in log4j-core)

Since version 2.6 it had only one PR/bug report and it was from PAX Logging maintainer. There is an alternative from a ZeroMQ maintainer, Fabrice Bacchella, that provides important features like encryption or choice of socket type.

JNDI-related features

JNDI is an old technology from the times of ponies and unicorns, when nobody cared about security. The Error Prone team decided to mark JNDI usage as error by default.

JPA appender (log4j-jpa)

Has marginal downloads and requires a migration to Jakarta EE. We think that log4j-jdbc (which is also seldom used) provides a good alternative for SQL databases.

Jackson-based layouts (Json-, Xml-, and YamlLayout in log4j-core)

JsonTemplateLayout supersedes JsonLayout; XmlLayout is seldom used, and YamlLayout, as far as we are concerned, is not be used at all.

MongoDB 3 appender (log4j-mongodb3)

Support for MongoDB 3 ended two years ago.

log4j-spring-boot

Its features are included in Spring Boot 3.x.

SMTP appender (SmtpAppender in log4j-core)

Its usage is at the bottom of the stats.

log4j-taglib

Needs a Jakarta version, but it is based on a legacy technology that is currently seldom used.

[garydgregory]

This all looks OK to me. The nice-to-have would be a migration guide.

[fbacchella]

If any one is interested in features provided by the JeroMqAppender but that are still missing in my own ZMQ appender, please fill free to contact me.

[vy]

The resolution is being voted.