Any CLI commands that depend on core Elasticsearch might touch classes
(directly or indirectly) that depends on logging. If they do this and
logging is not configured, Log4j will dump status error messages to the
console. As such, we need to ensure that any such CLI command configures
logging (with a trivial configuration that dumps log messages to the
console). Previously we did this in the base CLI command but with the
refactoring of this class out of core Elasticsearch, we no longer
configure logging there (since we did not want this class to depend on
settings and logging). However, this meant for some CLI commands (like
the plugin CLI) we were no longer configuring logging. This commit adds
base classes between the low-level command and multi-command classes
that ensure that logging is configured. Any CLI command that depends on
core Elasticsearch should use this infrastructure to ensure logging is
configured. There is one exception to this: Elasticsearch itself because
it takes reponsibility into its own hands for configuring logging from
Elasticsearch settings and log4j2.properties. We preserve this special
status.
Relates #27523
Projects the depend on the CLI currently depend on core. This should not
always be the case. The EnvironmentAwareCommand will remain in :core,
but the rest of the CLI components have been moved into their own
subproject of :core, :core:cli.
Jason Tedor
Michael Basnight