Replace purgeModule cache busting with vm based sandboxing
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krisselden
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The template compiler contents have to be evaluated separately for each addon in the build pipeline. If they are **not** the AST plugins from one addon leak through to other addons (or the app). This issue led us to attempt to purge the normal node require cache (the `purgeModule` code). This works (and has been in use for quite a while) but causes a non-trivial amount of memory overhead since each of the addons' ends up with a separate template compiler. This prevents JIT'ing and it causes the source code of the template compiler itself to be in memory many many many times (non-trivially increasing memory pressure). Migrating to `vm.Script` and sandboxed contexts (similar to what is done in FastBoot) resolves both of those issues. The script itself is cached and not reevaluated each time (removing the memory pressure issues) and the JIT information of the script context is also shared. Thanks to @krisselden for pointing out this improvement!
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This was referenced Feb 26, 2021
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This was referenced Mar 14, 2021
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The template compiler contents have to be evaluated separately for each addon in the build pipeline. If they are not the AST plugins from one addon leak through to other addons (or the app).
This issue led us to attempt to purge the normal node require cache (the
purgeModulecode). This works (and has been in use for quite a while) but causes a non-trivial amount of memory overhead since each of the addons' ends up with a separate template compiler. This prevents JIT'ing and it causes the source code of the template compiler itself to be in memory many many many times (non-trivially increasing memory pressure).Migrating to
vm.Scriptand sandboxed contexts (similar to what is done in FastBoot) resolves both of those issues. The script itself is cached and not reevaluated each time (removing the memory pressure issues) and the JIT information of the script context is also shared.Thanks to @krisselden for pointing out this improvement!