Fix context tracking with als run (#3571)

* Wrap the ContentType parsers in a AsyncResource to support AsyncLocalStorage

* Node v10 and v12 support

Signed-off-by: Matteo Collina <hello@matteocollina.com>

* removed spurious file

lib/contentTypeParser.js

@@ -1,5 +1,6 @@
 'use strict'
 
+const { AsyncResource } = require('async_hooks')
 let lru = require('tiny-lru')
 // Needed to handle Webpack and faux modules
 // See https://github.com/fastify/fastify/issues/2356
@@ -137,6 +138,7 @@ ContentTypeParser.prototype.remove = function (contentType) {
 
 ContentTypeParser.prototype.run = function (contentType, handler, request, reply) {
   const parser = this.cache.get(contentType) || this.getParser(contentType)
+  const resource = new AsyncResource('content-type-parser:run', request)
 
   if (parser === undefined) {
     reply.send(new FST_ERR_CTP_INVALID_MEDIA_TYPE(contentType))
@@ -163,12 +165,15 @@ ContentTypeParser.prototype.run = function (contentType, handler, request, reply
   }
 
   function done (error, body) {
-    if (error) {
-      reply.send(error)
-    } else {
-      request.body = body
-      handler(request, reply)
-    }
+    // We cannot use resource.bind() because it is broken in node v12.
+    resource.runInAsyncScope(() => {
+      if (error) {
+        reply.send(error)
+      } else {
+        request.body = body
+        handler(request, reply)
+      }
+    })
   }
 }
 

test/als.test.js

@@ -0,0 +1,74 @@
+'use strict'
+
+const { AsyncLocalStorage } = require('async_hooks')
+const t = require('tap')
+const Fastify = require('..')
+const sget = require('simple-get').concat
+
+if (!AsyncLocalStorage) {
+  t.skip('AsyncLocalStorage not available, skipping test')
+  process.exit(0)
+}
+
+const storage = new AsyncLocalStorage()
+const app = Fastify({ logger: false })
+
+let counter = 0
+app.addHook('onRequest', (req, reply, next) => {
+  const id = counter++
+  storage.run({ id }, next)
+})
+
+app.get('/', function (request, reply) {
+  t.ok(storage.getStore())
+  const id = storage.getStore().id
+  reply.send({ id })
+})
+
+app.post('/', function (request, reply) {
+  t.ok(storage.getStore())
+  const id = storage.getStore().id
+  reply.send({ id })
+})
+
+app.listen(3000, function (err, address) {
+  t.error(err)
+
+  sget({
+    method: 'POST',
+    url: 'http://localhost:' + app.server.address().port,
+    body: {
+      hello: 'world'
+    },
+    json: true
+  }, (err, response, body) => {
+    t.error(err)
+    t.equal(response.statusCode, 200)
+    t.same(body, { id: 0 })
+
+    sget({
+      method: 'POST',
+      url: 'http://localhost:' + app.server.address().port,
+      body: {
+        hello: 'world'
+      },
+      json: true
+    }, (err, response, body) => {
+      t.error(err)
+      t.equal(response.statusCode, 200)
+      t.same(body, { id: 1 })
+
+      sget({
+        method: 'GET',
+        url: 'http://localhost:' + app.server.address().port,
+        json: true
+      }, (err, response, body) => {
+        t.error(err)
+        t.equal(response.statusCode, 200)
+        t.same(body, { id: 2 })
+        app.close()
+        t.end()
+      })
+    })
+  })
+})