feat(gatsby-worker): Show original stack trace

packages/gatsby-worker/package.json

@@ -8,7 +8,9 @@
   },
   "dependencies": {
     "@babel/core": "^7.15.5",
-    "@babel/runtime": "^7.15.4"
+    "@babel/runtime": "^7.15.4",
+    "fs-extra": "^10.0.0",
+    "signal-exit": "^3.0.5"
   },
   "devDependencies": {
     "@babel/cli": "^7.15.4",

packages/gatsby-worker/src/__tests__/fixtures/test-child.ts

@@ -82,7 +82,12 @@ interface IPingMessage {
   type: `PING`
 }
 
-export type MessagesFromChild = IPingMessage
+interface ILotOfMessagesTestMessage {
+  type: `LOT_OF_MESSAGES_TEST`
+  payload: number
+}
+
+export type MessagesFromChild = IPingMessage | ILotOfMessagesTestMessage
 
 interface IPongMessage {
   type: `PONG`
@@ -97,6 +102,10 @@ let getWasPonged = function (): boolean {
   throw new Error(`gatsby-worker messenger not available`)
 }
 
+let lotOfMessagesAndExit = function (count: number): void {
+  throw new Error(`gatsby-worker messenger not available`)
+}
+
 const messenger = getMessenger<MessagesFromParent, MessagesFromChild>()
 if (messenger) {
   let wasPonged = false
@@ -126,6 +135,13 @@ if (messenger) {
   getWasPonged = function getWasPonged(): boolean {
     return wasPonged
   }
+
+  lotOfMessagesAndExit = function lotOfMessagesAndExit(count: number): boolean {
+    for (let i = 0; i < count; i++) {
+      messenger.sendMessage({ type: `LOT_OF_MESSAGES_TEST`, payload: i })
+    }
+    process.exit(1)
+  }
 }
 
-export { setupPingPongMessages, getWasPonged }
+export { setupPingPongMessages, getWasPonged, lotOfMessagesAndExit }

packages/gatsby-worker/src/__tests__/integration.ts

@@ -36,8 +36,8 @@ describe(`gatsby-worker`, () => {
       fail(`worker pool not created`)
     }
 
-    const exposedMethodsSingle = Object.keys(workerPool.single)
-    const exposedMethodsAll = Object.keys(workerPool.all)
+    const exposedMethodsSingle = Object.keys(workerPool.single).sort()
+    const exposedMethodsAll = Object.keys(workerPool.all).sort()
     // we expect that `notAFunction` even tho is exported in child module is not exposed
     // as it's not a function
     expect(exposedMethodsSingle).toMatchInlineSnapshot(`
@@ -46,6 +46,7 @@ describe(`gatsby-worker`, () => {
         "async100ms",
         "asyncThrow",
         "getWasPonged",
+        "lotOfMessagesAndExit",
         "neverEnding",
         "pid",
         "setupPingPongMessages",
@@ -426,5 +427,27 @@ describe(`gatsby-worker`, () => {
         workerPool.sendMessage({ type: `PONG` }, 9001)
       }).toThrowError(`There is no worker with "9001" id.`)
     })
+
+    it(`messages are not lost if worker exits soon after sending a message`, async () => {
+      if (!workerPool) {
+        fail(`worker pool not created`)
+      }
+      const COUNT = 10000
+
+      let counter = 0
+      workerPool.onMessage(msg => {
+        if (msg.type === `LOT_OF_MESSAGES_TEST`) {
+          counter++
+        }
+      })
+
+      try {
+        await workerPool.single.lotOfMessagesAndExit(COUNT)
+      } catch (e) {
+        console.log(e)
+      }
+
+      expect(counter).toEqual(COUNT)
+    })
   })
 })

packages/gatsby-worker/src/child.ts

@@ -1,3 +1,5 @@
+import signalExit from "signal-exit"
+import fs from "fs-extra"
 import {
   ParentMessageUnion,
   ChildMessageUnion,
@@ -10,6 +12,7 @@ import {
 } from "./types"
 import { isPromise } from "./utils"
 
+let counter = 0
 export interface IGatsbyWorkerMessenger<
   MessagesFromParent = unknown,
   MessagesFromChild = MessagesFromParent
@@ -30,12 +33,35 @@ let getMessenger = function <
   return undefined
 }
 
-if (process.send && process.env.GATSBY_WORKER_MODULE_PATH) {
+if (
+  process.send &&
+  process.env.GATSBY_WORKER_MODULE_PATH &&
+  process.env.GATSBY_WORKER_IN_FLIGHT_DUMP_LOCATION
+) {
+  const workerInFlightsDumpLocation =
+    process.env.GATSBY_WORKER_IN_FLIGHT_DUMP_LOCATION
   isWorker = true
   const listeners: Array<(msg: any) => void> = []
-  const ensuredSendToMain = process.send.bind(process) as (
-    msg: ChildMessageUnion
-  ) => void
+
+  const inFlightMessages = new Set<ChildMessageUnion>()
+  signalExit(() => {
+    if (inFlightMessages.size > 0) {
+      // this need to be sync
+      fs.outputJsonSync(
+        workerInFlightsDumpLocation,
+        Array.from(inFlightMessages)
+      )
+    }
+  })
+
+  function ensuredSendToMain(msg: ChildMessageUnion): void {
+    inFlightMessages.add(msg)
+    process.send!(msg, undefined, undefined, error => {
+      if (!error) {
+        inFlightMessages.delete(msg)
+      }
+    })
+  }
 
   function onError(error: Error): void {
     if (error == null) {
@@ -44,6 +70,7 @@ if (process.send && process.env.GATSBY_WORKER_MODULE_PATH) {
 
     const msg: ChildMessageUnion = [
       ERROR,
+      ++counter,
       error.constructor && error.constructor.name,
       error.message,
       error.stack,
@@ -54,7 +81,7 @@ if (process.send && process.env.GATSBY_WORKER_MODULE_PATH) {
   }
 
   function onResult(result: unknown): void {
-    const msg: ChildMessageUnion = [RESULT, result]
+    const msg: ChildMessageUnion = [RESULT, ++counter, result]
     ensuredSendToMain(msg)
   }
 
@@ -69,7 +96,7 @@ if (process.send && process.env.GATSBY_WORKER_MODULE_PATH) {
         listeners.push(listener)
       },
       sendMessage(msg: MessagesFromChild): void {
-        const poolMsg: ChildMessageUnion = [CUSTOM_MESSAGE, msg]
+        const poolMsg: ChildMessageUnion = [CUSTOM_MESSAGE, ++counter, msg]
         ensuredSendToMain(poolMsg)
       },
       messagingVersion: MESSAGING_VERSION,
@@ -82,7 +109,7 @@ if (process.send && process.env.GATSBY_WORKER_MODULE_PATH) {
     if (msg[0] === EXECUTE) {
       let result
       try {
-        result = child[msg[1]].call(child, ...msg[2])
+        result = child[msg[2]].call(child, ...msg[3])
       } catch (e) {
         onError(e)
         return
@@ -97,14 +124,14 @@ if (process.send && process.env.GATSBY_WORKER_MODULE_PATH) {
       process.off(`message`, messageHandler)
     } else if (msg[0] === CUSTOM_MESSAGE) {
       for (const listener of listeners) {
-        listener(msg[1])
+        listener(msg[2])
       }
     }
   }
 
   process.on(`message`, messageHandler)
 
-  ensuredSendToMain([WORKER_READY])
+  ensuredSendToMain([WORKER_READY, ++counter])
 }
 
 export { isWorker, getMessenger }