feat(server): verify INTERNAL_ADDRESS is reachable and correct (#430)

src/server.js

@@ -1,12 +1,18 @@
 const app = require('./app'),
     logger = require('./common/logger'),
+    request = require('request-promise-native'),
+    configHandler = require('./configManager/models/configHandler'),
+    constConfig = require('./common/consts').CONFIG,
     shutdown = require('graceful-shutdown-express');
 
-app().then(app => {
+app().then(async (app) => {
     const serverPort = process.env.PORT || '80';
     const server = app.listen(serverPort, function () {
         logger.info('Predator listening on port ' + serverPort);
     });
+
+    await verifyInternalAddressReachable();
+
     shutdown.registerShutdownEvent({
         server: server,
         newConnectionsTimeout: process.env.LOAD_BALANCER_UPDATE_PERIOD || 7000,
@@ -18,3 +24,24 @@ app().then(app => {
     logger.error(error, 'Encountered an error during start up');
     process.exit(1);
 });
+
+async function verifyInternalAddressReachable() {
+    if (process.env.SKIP_INTERNAL_ADDRESS_CHECK === 'true') {
+        logger.info('Skipping verify internal address check');
+        return;
+    }
+
+    const internalConfigAddress = await configHandler.getConfigValue(constConfig.INTERNAL_ADDRESS) + '/config';
+    logger.info(`Checking ${internalConfigAddress} to verify predator-runners will be able connect to Predator`);
+    if (internalConfigAddress.includes('localhost') || internalConfigAddress.includes('127.0.0.1')) {
+        logger.warn('INTERNAL_ADDRESS set to localhost, Predator runners may not be able connect Predator if running inside docker bridge mode or in different networks');
+    }
+
+    const response = await request.get(internalConfigAddress, { json: true, simple: false, resolveWithFullResponse: true, timeout: 5000 });
+
+    if (response.statusCode !== 200 || !response.body.internal_address) {
+        throw new Error(`Failed to reach successfully INTERNAL_ADDRESS at ${internalConfigAddress}, shutting down server (to skip this check set SKIP_INTERNAL_ADDRESS_CHECK=true\nError: ${response.body}`);
+    } else {
+        logger.info(`${internalConfigAddress} successfully reached`);
+    }
+}