Messy tests with mustache were either moved to core, moved to a rest test or remained untouched if they actually tested mustache.
Also removed tests that were redundant.
* Removed `Template` class and unified script & template parsing logic. Templates are scripts, so they should be defined as a script. Unless there will be separate template infrastructure, templates should share as much code as possible with scripts.
* Removed ScriptParseException in favour for ElasticsearchParseException
* Moved TemplateQueryBuilder to lang-mustache module because this query is hard coded to work with mustache only
This commit moves template support out of the Search API to its own dedicated Search Template API in the lang-mustache module. It provides a new SearchTemplateAction that can be used to render templates before it gets delegated to the usual Search API. The current REST endpoint are identical, but the Render Search Template endpoint now uses the same Search Template API with a new "simulate" option. When this option is enabled, the Search Template API only renders template and returns immediatly, without executing the search.
Closes#17906
Today, certain bootstrap properties are set and read via system
properties. This action-at-distance way of managing these properties is
rather confusing, and completely unnecessary. But another problem exists
with setting these as system properties. Namely, these system properties
are interpreted as Elasticsearch settings, not all of which are
registered. This leads to Elasticsearch failing to startup if any of
these special properties are set. Instead, these properties should be
kept as local as possible, and passed around as method parameters where
needed. This eliminates the action-at-distance way of handling these
properties, and eliminates the need to register these non-setting
properties. This commit does exactly that.
Additionally, today we use the "-D" command line flag to set the
properties, but this is confusing because "-D" is a special flag to the
JVM for setting system properties. This creates confusion because some
"-D" properties should be passed via arguments to the JVM (so via
ES_JAVA_OPTS), and some should be passed as arguments to
Elasticsearch. This commit changes the "-D" flag for Elasticsearch
settings to "-E".
We have two similar tests with the same name, ContextAndHeaderTransportTests.
They shared lots of common code so I extracted much of it into
ActionRecordingPlugin, a plugin which records all action requests for later
inspection.
I also removed all the warnings from both tests. That made lang-mustache
compile cleanly without any custom -Xlint so I removed those. To remove
the warnings I had to add type parameters to ActionFilter which seemed
like a good idea anyway.