Dev server restart time

[mshustov]

Kibana restarts the server in dev mode whenever the server-side code has been changed. However, I felt the server restart is extremely slow (~40sec. on my high-end laptop) and decided to figure a reason. Turned out, Kibana spends 90% of that time compiling js code with babel-register. Several problems need solving:

• the platform always imports and re-compiles plugin server-side code, even if a plugin is disabled. That's a downside of the current implementation of the plugin config schema declaration.

  kibana/src/core/server/plugins/plugin.ts

  Line 141 in 744a7b1

  const pluginDefinition = require(pluginPathServer);

  
  In a long term, we might need to reconsider our approach to code compilation in dev: do not compile disabled plugins, speed up compilation, use a single compiler(created Dev server restart time #77298 to discuss) etc.
• I can often observe babel-register throwing OOM exception when writing cache to the disk during server restart. As a result, the cache is not updated and won't be used when re-compiling. From my testing, it seems that with re-used cache the compilation takes ~15sec, without ~40sec.
  As a short term solution, we could increase the memory limit for nodejs process in dev mode to ensure babel writes its cache to the disk.

[elasticmachine]

Pinging @elastic/kibana-operations (Team:Operations)

[elasticmachine]

Pinging @elastic/kibana-platform (Team:Platform)

[mshustov]

the slow compilation problem solved by
#79052
#79358