fastify-sandbox
Loads a fastify plugin in a sandbox. It will have a different require.cache, so loaded modules could be safely gc'ed once the sandbox goes out of scope.
The plugin can be both commonjs or esm.
This modules pairs well with @fastify/restartable
to provide hot-reloading mechanism for Fastify applications.
Install
npm i fastify-sandbox
Usage
'use strict'
const Fastify = require('fastify')
const sandbox = require('fastify-sandbox')
const app = Fastify()
app.addHook('onRequest', async function (req) {
req.p = Promise.resolve('hello')
console.log('promise constructor is the same', Object.getPrototypeOf(req.p).constructor === Promise)
})
app.register(sandbox, {
path: __dirname + '/plugin.js',
options: { // this object will be passed as the options of the loaded plugin
hello: "world"
},
onError (err) {
// uncaught exceptions within the sandbox will land inside this
// callback
}
})
app.listen(3000)
Inside plugin.js
:
'use strict'
// We are in a different V8 Context now
const sleep = require('timers/promises').setTimeout
module.exports = async function (app) {
app.get('/', async (req, res) => {
console.log('promise constructor is different', Object.getPrototypeOf(req.p).constructor === Promise)
return 'Hello World!'
})
}
Missing compiler support
In case there is no compiler toolchain available in the system, compiling the code needed to support for the current Node.js version would be impossible. In this case we rely on import-fresh instead.
It's also possible to turn on the fallback mechanism with the fallback: true
option:
'use strict'
const Fastify = require('fastify')
const sandbox = require('fastify-sandbox')
const app = Fastify()
app.addHook('onRequest', async function (req) {
req.p = Promise.resolve('hello')
console.log('promise constructor is the same', Object.getPrototypeOf(req.p).constructor === Promise)
})
app.register(sandbox, {
path: __dirname + '/plugin.js',
fallback: true
})
app.listen(3000)
Note that ESM is only supported via the native code.
Caveats
This module does not offer any protection against malicious code.
License
MIT