Allow autoConfig with callback

[jean-michelet]

Can be usefull to autoload plugins:

import fastifyMysql from "@fastify/mysql";

export const autoConfig = (fastify) => {
  return {
    promise: true,
    host: fastify.config.MYSQL_HOST,
    user: fastify.config.MYSQL_USER,
    password: fastify.config.MYSQL_PASSWORD,
    database: fastify.config.MYSQL_DATABASE,
    port: Number(fastify.config.MYSQL_PORT)
  }
}

export default fastifyMysql

[jean-michelet]

That might do the job, but I think the whole component would benefit greatly from a major refactoring.
Right now, it really looks spaghetti code imho, it's hard to introduce changes cleanly.

EDIT: maybe with:

pluginOptions.prefix = overrideConfig.prefix ?? pluginConfig.prefix

[jean-michelet]

Open to work on it btw, but after the demo.

[mcollina]

That'd be fantastic, thx 'b

[jean-michelet]

See #383

[mcollina]

lgtm

[mcollina]

@climba03003 ptal

[climba03003]

LGTM