Add support in plugins for a separate spi classloader (#76288)#76364
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elasticsearchmachine merged 1 commit intoelastic:7.xfrom Aug 11, 2021
Merged
Add support in plugins for a separate spi classloader (#76288)#76364elasticsearchmachine merged 1 commit intoelastic:7.xfrom
elasticsearchmachine merged 1 commit intoelastic:7.xfrom
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SPI is how plugins provide extension points for other plugins to customize their behavior. Plugins may have a separate SPI jar, so as not to expose the internals of the plugin implementation. In essense, this system was built as a stopgap for Java modules, where implementation can be protected in the same jar. However, currently the plugins service loads both spi and plugin implementations into the same classloader. This means that although another plugin may only compile against spi, they could still get jar hell from a duplicate dependency. This commit adds support for plugins to contain an "spi" subdirectory which is loaded into a separate classloader. This spi classloader is a parent to the plugin implementation, as well as any other plugins which have extended it. Additionally as a demonstration of how this works in practice, lang-painless is setup as the first plugin to provide an spi jar, and sql's dependence on painless is changed to only spi, so that it now has an independent version of antlr. closes elastic#74448
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SPI is how plugins provide extension points for other plugins to
customize their behavior. Plugins may have a separate SPI jar, so as not
to expose the internals of the plugin implementation. In essense, this
system was built as a stopgap for Java modules, where implementation can
be protected in the same jar. However, currently the plugins service
loads both spi and plugin implementations into the same classloader.
This means that although another plugin may only compile against spi,
they could still get jar hell from a duplicate dependency.
This commit adds support for plugins to contain an "spi" subdirectory
which is loaded into a separate classloader. This spi classloader is a
parent to the plugin implementation, as well as any other plugins which
have extended it. Additionally as a demonstration of how this works in
practice, lang-painless is setup as the first plugin to provide an spi
jar, and sql's dependence on painless is changed to only spi, so that
it now has an independent version of antlr.
closes #74448