This commit adds the Log4j to SLF4J binding JAR to the repository-hdfs
plugin so that SLF4J can detect Log4j at runtime and therefore use the
server Log4j implementation for logging (and the usual Elasticsearch
APIs can be used for setting logging levels).
Relates #26514
Hadoop 2.7.x libraries fail when running on JDK9 due to the version string changing to a single
character. On Hadoop 2.8, this is no longer a problem, and it is unclear on whether the fix will be
backported to the 2.7 branch. This commit upgrades our dependency of Hadoop for the HDFS
Repository to 2.8.1.
This commit sets the version on the repository-hdfs Guava dependency to
version 11.0.2. This change is made to align the version here with the
version that is defined in the POM for Hadoop 2.7.1, the version of
Hadoop that the repository-hdfs plugin is based on. See HADOOP-10101 and
HADOOP-11319 for the ridiculous history of trying to upgrade Guava past
this version in the Hadoop project.
Relates #23420
Removes all our logger wrappers except the wrapper for log4j1.2. If you
depend on Elasticsearch's jar in your application you'll need to declare
log4j 1.2 and/or some bridge to your favorite logger.
We did this to simplify our builds and code. No more commons-logging like
log implementation sniffing. No more optional dependency hacks in gradle.
We might one day want to use j.u.l instead of log4j. If we do want that
we can recover its wrapper by studying this commit. We didn't go directly
to j.u.l in this commit because that is a bigger change. Our logging
configuration is based on log4j1.2 and people are used to it. So it'd
be a much more fraught breaking change to do that conversion.
Jason Tedor
James Baiera
Ryan Ernst
Nik Everett
Robert Muir