Fix error handling if lambda throws while launching

Author: mantoni

lib/lambda.js

@@ -381,9 +381,13 @@ exports.create = function (base_options = {}) {
           );
         } catch (e) {
           log.error('Failed to launch Lambda', { name, base_dir }, e);
-          // eslint-disable-next-line node/no-callback-literal
-          callback(`{"message":"Failed to launch \\"${name}\\""}`);
-          return;
+          const message = `{"message":"Failed to launch \\"${name}\\""}`;
+          if (callback) {
+            callback(message);
+            return;
+          }
+          // eslint-disable-next-line consistent-return
+          return Promise.reject(message);
         }
       }
       if (!callback) {

test/fixture/functions/env-file-async/function.local.json

@@ -0,0 +1,6 @@
+{
+  "environment": {
+    "STUDIO_ENV_VAR": "Hello",
+    "STUDIO_ENV_TPL": "${STUDIO_ENVIRONMENT_VARIABLE}"
+  }
+}

test/fixture/functions/env-file-async/index.js

@@ -0,0 +1,10 @@
+'use strict';
+
+exports.handle = function () {
+  return new Promise((resolve, reject) => {
+    setTimeout(() => {
+      // eslint-disable-next-line prefer-promise-reject-errors
+      reject(`${process.env.STUDIO_ENV_VAR} ${process.env.STUDIO_ENV_TPL}`);
+    }, 1);
+  });
+};

test/lambda-test.js

@@ -355,6 +355,23 @@ describe('lambda', () => {
     });
   });
 
+  it('fails to launch async lambda if environment variable is missing', async () => {
+    lambda = Lambda.create({
+      env: {
+        AWS_PROFILE: 'local'
+      }
+    });
+
+    const promise = lambda.invoke('env-file-async');
+
+    await assert.rejects(
+      promise,
+      match.json({
+        message: 'Failed to launch "env-file-async"'
+      })
+    );
+  });
+
   it('invokes lambda with DEBUG environment variables', (done) => {
     process.env.DEBUG = 'ON';