From 5d93b1d4f9fcbbd0ffe002b79c72cf3fac3e4fcc Mon Sep 17 00:00:00 2001
From: Petr Sloup <slouppetr@gmail.com>
Date: Wed, 10 May 2017 08:57:51 +0200
Subject: [PATCH] Add healthcheck endpoint (close #140)

---
 docs/endpoints.rst | 7 +++++++
 src/server.js      | 9 +++++++++
 test/metadata.js   | 8 ++++++++
 3 files changed, 24 insertions(+)

diff --git a/docs/endpoints.rst b/docs/endpoints.rst
index 3128085..91371bf 100644
--- a/docs/endpoints.rst
+++ b/docs/endpoints.rst
@@ -64,3 +64,10 @@ Array of all TileJSONs is at ``/index.json`` (``/rendered.json``; ``/data.json``
 List of available fonts
 =======================
 Array of names of the available fonts is at ``/fonts.json``
+
+Health check
+============
+Endpoint reporting health status is at ``/health`` and currently returns:
+
+  * ``503`` Starting - for a short period before everything is initialized
+  * ``200`` OK - when the server is running
diff --git a/src/server.js b/src/server.js
index 1ebd59c..9657193 100644
--- a/src/server.js
+++ b/src/server.js
@@ -375,8 +375,17 @@ function start(opts) {
     return data;
   });
 
+  var startupComplete = false;
   var startupPromise = Promise.all(startupPromises).then(function() {
     console.log('Startup complete');
+    startupComplete = true;
+  });
+  app.get('/health', function(req, res, next) {
+    if (startupComplete) {
+      return res.status(200).send('OK');
+    } else {
+      return res.status(503).send('Starting');
+    }
   });
 
   var server = app.listen(process.env.PORT || opts.port, process.env.BIND || opts.bind, function() {
diff --git a/test/metadata.js b/test/metadata.js
index 647ee92..1365400 100644
--- a/test/metadata.js
+++ b/test/metadata.js
@@ -38,6 +38,14 @@ var testTileJSON = function(url) {
 };
 
 describe('Metadata', function() {
+  describe('/health', function() {
+    it('returns 200', function(done) {
+      supertest(app)
+        .get('/health')
+        .expect(200, done);
+    });
+  });
+
   testTileJSONArray('/index.json');
   testTileJSONArray('/rendered.json');
   testTileJSONArray('/data.json');