Add node version warning

package.json

@@ -5,7 +5,8 @@
     "google-protobuf": "^3.0.0",
     "grpc": "^1.6.0",
     "minimist": "^1.2.0",
-    "protobufjs": "6.7.0"
+    "protobufjs": "6.7.0",
+    "semver": "^5.4.1"
   },
   "devDependencies": {
     "@types/mocha": "^2.2.41",

src/Worker.ts

@@ -1,4 +1,5 @@
 import * as parseArgs from 'minimist';
+import * as semver from 'semver';
 
 import { FunctionRpc as rpc } from '../protos/rpc';
 import Status = rpc.StatusResult.Status;
@@ -13,6 +14,12 @@ export function startNodeWorker(args) {
     throw new Error('Connection info missing');
   }
 
+  if (!semver.satisfies(process.version, '>=8.4.0')) {
+    console.error(`azure-functions-nodejs-worker officially supports node version >=8.4.0. Current version ${process.version}.
+To install required native modules for ${process.version}, install node-pre-gyp via 'npm i -g node-pre-gyp'.
+Navigate to '<node-worker-dir>/grpc' and run 'node-pre-gyp install'`);
+  }
+
   let connection = `${host}:${port}`;
   console.log(`Worker ${workerId} connecting on ${connection}`);
   let eventStream = CreateGrpcEventStream(connection);

src/nodejsWorker.ts

@@ -1,3 +1,9 @@
-var worker = require("../../worker-bundle.js")
+var worker;
+try {
+    worker = require("../../worker-bundle.js");
+} catch (err) {
+    console.error(`Couldn't require bundle, falling back to Worker.js. ${err}`);
+    worker = require("./Worker.js");
+}
 
 worker.startNodeWorker(process.argv);