From ec4b9ce536f4f28325c44cf3f1eb28e458ceb368 Mon Sep 17 00:00:00 2001
From: Atul Varma <varmaa@gmail.com>
Date: Mon, 3 Jun 2013 18:56:00 -0400
Subject: [PATCH] No more killing the server at startup if healthcheck fails.

However, we do print a big red message telling anyone watching that
things are seriously messed up.
---
 app.js                      | 17 +++++++++++------
 controllers/health-check.js | 26 ++++++++++++++++++++++++--
 package.json                |  2 +-
 3 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/app.js b/app.js
index 1e74962..20f51f2 100644
--- a/app.js
+++ b/app.js
@@ -1,6 +1,7 @@
 if ( process.env.NEW_RELIC_HOME ) {
   require( 'newrelic' );
 }
+const colors = require('colors');
 const path = require('path');
 const http = require('http');
 const express = require('express');
@@ -62,16 +63,20 @@ if (!module.parent)
   app.listen(port, function(err) {
     if (err) throw err;
     console.log("Listening on port " + port + ".");
-    console.log("Performing health check.");
+    console.log("Performing health check.\n");
 
     healthChecker.runChecks(function(results) {
+      var consoleStr = healthCheck.resultsToConsoleString(results);
+      console.log("Health check results:\n");
       if (results.status != "OK") {
-        console.error("Health check failed:",
-                      JSON.stringify(results, null, 2));
-        console.error("Please resolve the problem and restart the server.");
-        process.exit(1);
+        console.error(consoleStr + "\n");
+        console.error(("One or more critical services are down or " +
+                       "misconfigured. Please fix them!").red.bold);
+      } else {
+        console.log(consoleStr);
+        console.log(("\nHealth check indicates all systems are " +
+                     "functional.").green);
       }
-      console.log("Health check indicates all systems are functional.");
     });
   });
 else
diff --git a/controllers/health-check.js b/controllers/health-check.js
index ef084b4..f82d03f 100644
--- a/controllers/health-check.js
+++ b/controllers/health-check.js
@@ -1,15 +1,16 @@
 // TODO: Separate this module out into its own npm module/git repo.
 
 var async = require('async');
+var colors = require('colors');
 
-const HEALTH_CHECK_TIMEOUT = 15000;
+const CHECKMARK = "\u2713";
 
 function checker(fn) {
   return function check(cb) {
     var timeout = setTimeout(function() {
       timeout = null;
       cb(null, {status: "FAILED", reason: "TIMEOUT"});
-    }, HEALTH_CHECK_TIMEOUT);
+    }, module.exports.TIMEOUT);
 
     try {
       fn(function(err) {
@@ -71,6 +72,25 @@ function runChecks(checks, cb) {
   });
 }
 
+function resultsToConsoleString(results) {
+  var lines = [];
+
+  Object.keys(results).forEach(function(name) {
+    var info = results[name];
+
+    if (info && typeof(info) == "object" && info.status) {
+      if (info.status == "OK") {
+        lines.push(CHECKMARK.green + " " + name.grey);
+      } else {
+        lines.push("x".red + " " + name.grey + " " +
+                   (info.reason ? info.reason : ""));
+      }
+    }
+  });
+
+  return lines.join('\n');
+}
+
 module.exports = function healthCheck(options) {
   var authenticate = options.auth || function(req, res, next) { next(); };
   var checks = options.checks;
@@ -92,6 +112,8 @@ module.exports = function healthCheck(options) {
   return healthChecker;
 };
 
+module.exports.TIMEOUT = 15000;
+module.exports.resultsToConsoleString = resultsToConsoleString;
 module.exports.runChecks = runChecks;
 module.exports.sessionStorageChecker = sessionStorageChecker;
 module.exports.checker = checker;
diff --git a/package.json b/package.json
index b2eeeaf..6203912 100644
--- a/package.json
+++ b/package.json
@@ -19,12 +19,12 @@
     "underscore": "~1.4.4",
     "winston": "~0.7.1",
     "newrelic": "~0.9.19",
+    "colors": "~0.6.0",
     "jwt-simple": "~0.1.0"
   },
   "devDependencies": {
     "sinon": "~1.7.2",
     "injectr": "~0.4.0",
-    "colors": "~0.6.0",
     "optimist": "~0.5.2",
     "up": "~0.2.2"
   },