Health endpoint verifies Druid brokers' health and readiness

README.md

@@ -66,6 +66,7 @@ turnilo --druid broker_host:broker_port
 
 * [Configuration](docs/configuration.md)
 * [Generating Links](docs/generating-links.md)
+* [Health checking](docs/health-checking.md)
 
 ## Development
 

docs/configuration.md

@@ -42,6 +42,10 @@ A custom path to act as the server string.
 
 The Turnilo UI will be served from `http://turnilo-host:$port/` and `http://turnilo-host:$port/$serverRoot`
 
+**healthEndpoint** (string), default "/health"
+
+A health endpoint location. See [Checking health of Turnilo instance](health-checking.md)
+
 **iframe** ("allow" | "deny"), default "allow"
 
 Specify whether Turnilo will be allowed to run in an iFrame.
@@ -97,6 +101,10 @@ Define this to override the automatic version detection.
 
 The timeout to set on the queries in ms.
 
+**healthCheckingTimeout** (number), default: 1000
+
+The timeout for the cluster health checking request in ms. See [Checking health of Turnilo instance](health-checking.md)
+
 **sourceListScan** ("auto" | "disable"), default: "auto"
 
 Should the sources of this cluster be automatically scanned and new sources added as data cubes.

docs/health-checking.md

@@ -0,0 +1,56 @@
+# Checking health of Turnilo instance
+
+Turnilo instance's health is defined in terms of being able to communicate with all configured Druid brokers
+and those brokers knowing about all segments in Zookeeper.
+
+It can be checked by sending a GET request to a `healthEndpoint` path defined in Turnilo's server [configuration](configuration.md).
+
+Healthy Turnilo instance responds with HTTP status 200 while an unhealthy one responds with the status of 500.
+The body of a response contains health status of all configured brokers with optional error message on unhealthy brokers.
+
+While processing the health checking request Turnilo server will send its own requests to all configured
+druid clusters' brokers for `/druid/broker/v1/loadstatus` endpoint. It will check that all brokers responds within
+individually defined cluster timeout (`healthCheckingTimeout` property in [cluster properties](configuration.md#general-properties))
+and that the response body contains `inventoryInitialized` flag set to `true`.
+If any of the requests to brokers fail to meet the criteria defined above the Turnilo instance is marked as unhealthy.
+
+# Response examples
+
+Healthy response example:
+```
+HTTP/1.1 200 OK
+Content-Type: application/json; charset=utf-8
+
+{
+    "clusters": [
+        {
+            "host": "localhost:8082",
+            "message": "",
+            "status": "healthy"
+        }
+    ],
+    "status": "healthy"
+}
+```
+
+Unhealthy response example:
+```
+HTTP/1.1 500 Internal Server Error
+Content-Type: application/json; charset=utf-8
+
+{
+    "clusters": [
+        {
+            "host": "localhost:8082",
+            "message": "inventory not initialized",
+            "status": "unhealthy"
+        },
+        {
+            "host": "192.168.99.100:8082",
+            "message": "connection error: 'Error: ESOCKETTIMEDOUT'",
+            "status": "unhealthy"
+        }
+    ],
+    "status": "unhealthy"
+}
+```

package.json

@@ -81,7 +81,8 @@
     "react-dom": "16.2.0",
     "react-syntax-highlighter": "7.0.2",
     "react-copy-to-clipboard": "5.0.1",
-    "request": "2.83.0"
+    "request": "2.83.0",
+    "request-promise-native": "1.0.5"
   },
   "devDependencies": {
     "@types/body-parser": "1.16.8",
@@ -100,22 +101,24 @@
     "@types/mime": "2.0.0",
     "@types/mocha": "2.2.46",
     "@types/moment-timezone": "0.5.4",
+    "@types/nock": "9.1.3",
     "@types/node": "8.5.2",
     "@types/nopt": "3.0.29",
     "@types/numeral": "0.0.22",
     "@types/q": "1.0.6",
     "@types/qajax": "0.0.29",
     "@types/react": "16.0.40",
+    "@types/react-copy-to-clipboard": "4.2.5",
     "@types/react-dom": "16.0.4",
+    "@types/react-syntax-highlighter": "0.0.5",
     "@types/react-transition-group": "2.0.7",
+    "@types/request-promise-native": "^1.0.14",
     "@types/rewire": "2.5.28",
     "@types/sinon": "4.1.4",
     "@types/superagent": "3.5.6",
     "@types/supertest": "2.0.4",
     "@types/webpack": "3.8.10",
     "@types/webpack-env": "1.13.3",
-    "@types/react-syntax-highlighter": "0.0.5",
-    "@types/react-copy-to-clipboard": "4.2.5",
     "awesome-typescript-loader": "3.4.1",
     "chai": "4.1.2",
     "create-react-class": "15.6.2",
@@ -125,6 +128,7 @@
     "immutable-class-tester": "0.5.12",
     "jsdom": "9.4.2",
     "mocha": "4.1.0",
+    "nock": "9.2.5",
     "node-sass": "4.7.2",
     "npm-run-all": "4.1.2",
     "react-hot-loader": "3.1.3",

src/client/components/immutable-input/immutable-input.mocha.tsx

@@ -138,7 +138,7 @@ describe('ImmutableInput', () => {
     });
 
     it('works for valid values', () => {
-      expect(node.value).to.equal('DRUID');
+      expect(node.value).to.equal('DRUID-TWITTER');
 
       node.value = 'GIRAFFE';
       TestUtils.Simulate.change(node);
@@ -157,7 +157,7 @@ describe('ImmutableInput', () => {
     });
 
     it('works when an error is thrown', () => {
-      expect(node.value).to.equal('DRUID');
+      expect(node.value).to.equal('DRUID-TWITTER');
 
       node.value = 'PLATYPUS';
       TestUtils.Simulate.change(node);

src/common/models/app-settings/app-settings.mocha.ts

@@ -39,7 +39,7 @@ describe('AppSettings', () => {
     it("errors if there is no matching cluster", () => {
       var js = AppSettingsMock.wikiOnlyJS();
       js.clusters = [];
-      expect(() => AppSettings.fromJS(js, context)).to.throw("Can not find cluster 'druid' for data cube 'wiki'");
+      expect(() => AppSettings.fromJS(js, context)).to.throw("Can not find cluster 'druid-wiki' for data cube 'wiki'");
     });
 
   });
@@ -90,7 +90,7 @@ describe('AppSettings', () => {
         druidHost: '192.168.99.100',
         sourceListScan: 'disable',
         dataSources: [
-          DataCubeMock.WIKI_JS
+          { ...DataCubeMock.WIKI_JS, clusterName: "druid" }
         ]
       };
 
@@ -122,7 +122,7 @@ describe('AppSettings', () => {
       expect(settings.toClientSettings().toJS()).to.deep.equal({
         "clusters": [
           {
-            "name": "druid",
+            "name": "druid-wiki",
             "type": "druid"
           }
         ],
@@ -159,7 +159,7 @@ describe('AppSettings', () => {
                 "unsplitable": true
               }
             ],
-            "clusterName": "druid",
+            "clusterName": "druid-wiki",
             "defaultDuration": "P3D",
             "defaultFilter": {
               "op": "literal",