change callback into promise

README.md

@@ -67,6 +67,8 @@ const req = {
   body: { x: 10, y: 10}
 };
 
+const taskId = `${namespace}/${id}-${Date.now()}`; //or can be any uniq id
+
 executeFunctionInSandbox(taskId, {
   env: {
     MY_VAR: 'TRUE', // environment variable will be available on Backstage.env.MY_VAR
@@ -79,14 +81,14 @@ executeFunctionInSandbox(taskId, {
   namespace: "foo",
   functionName: "bar",
   options,
-}, (result) => { // when result callback was called, the child process of sandbox execution will be died
-  if(result.error) {
-    console.error({ error: err.message || err }) //print error return from function execution
-  }
-
-  console.log(result) //print return from function execution
 })
-
+/* can return result using callback or using async await */
+.then(result => {
+  console.log(result)
+})
+.catch(err => {
+  console.log(err)
+})
 ```
 
 ## Configuration

lib/ForkSandbox.js

@@ -3,25 +3,28 @@ const child_process = require('child_process');
 
 const Sandbox = require("./Sandbox");
 
-const tasks = {};
 const childs = {};
 
 const codeFileName = (namespace, codeId) => {
   return `${namespace}/${codeId}.js`;
 }
 
-const executeFunctionInSandbox = (id, data, callback) => {
-
-  childs[id] = child_process.fork(path.resolve(__filename)); //require this file to execute process.on('message') below
+const executeFunctionInSandbox = (id, data) => {
+  return new Promise((resolve, reject) => {
+    childs[id] = child_process.fork(path.resolve(__filename)); //require this file to execute process.on('message') below
+
+    childs[id].send({ id, data });
 
-  childs[id].send({ id, data });
-  tasks[id] = callback;
+    childs[id].on('message', (message) => {
+      const result = message;
+      if (result.error) {
+        reject(result.error);
+      }
+
+      resolve(result.data);
+      delete childs[id];
 
-  childs[id].on('message', (message) => {
-    const result = message.data;
-    tasks[message.id](result);
-    delete tasks[id];
-    delete childs[id];
+    });
   });
 }
 
@@ -36,8 +39,15 @@ process.on('message', async (message) => {
     const sandbox = new Sandbox({ env, globalModules, asyncTimeout, syncTimeout, config });
     const filename = codeFileName(namespace, functionName);
 
+    const _req = Object.assign({
+      method: null,
+      headers: {},
+      body: {},
+      query: {},
+    }, req);
+
     const script = sandbox.compileCode(filename, preCode.code)
-    const result = await sandbox.runScript(script, req, options);
+    const result = await sandbox.runScript(script, _req, options);
     process.send({ id, data: result });
     process.exit(0);
   } catch (ex) {