[es/healthcheck] ensure that healthcheck stops when server is stopped (…

…elastic#13201)

(cherry picked from commit 9245488)

src/core_plugins/elasticsearch/lib/__tests__/health_check.js

@@ -23,12 +23,17 @@ describe('plugins/elasticsearch', () => {
     let plugin;
     let cluster;
     let server;
+    const sandbox = sinon.sandbox.create();
+
+    function getTimerCount() {
+      return Object.keys(sandbox.clock.timers || {}).length;
+    }
 
     beforeEach(() => {
       const COMPATIBLE_VERSION_NUMBER = '5.0.0';
 
       // Stub the Kibana version instead of drawing from package.json.
-      sinon.stub(kibanaVersion, 'get').returns(COMPATIBLE_VERSION_NUMBER);
+      sandbox.stub(kibanaVersion, 'get').returns(COMPATIBLE_VERSION_NUMBER);
 
       // setup the plugin stub
       plugin = {
@@ -55,7 +60,7 @@ describe('plugins/elasticsearch', () => {
         }
       }));
 
-      sinon.stub(determineEnabledScriptingLangsNS, 'determineEnabledScriptingLangs').returns(Promise.resolve([]));
+      sandbox.stub(determineEnabledScriptingLangsNS, 'determineEnabledScriptingLangs').returns(Promise.resolve([]));
 
       // setup the config().get()/.set() stubs
       const get = sinon.stub();
@@ -74,15 +79,37 @@ describe('plugins/elasticsearch', () => {
           elasticsearch: {
             getCluster: sinon.stub().returns(cluster)
           }
-        }
+        },
+        ext: sinon.stub()
       };
 
       health = healthCheck(plugin, server, { mappings });
     });
 
     afterEach(() => {
-      kibanaVersion.get.restore();
-      determineEnabledScriptingLangs.restore();
+      sandbox.restore();
+    });
+
+    it('should stop when cluster is shutdown', () => {
+      sandbox.useFakeTimers();
+
+      // ensure that health.start() is responsible for the timer we are observing
+      expect(getTimerCount()).to.be(0);
+      health.start();
+      expect(getTimerCount()).to.be(1);
+
+      // ensure that a server extension was registered
+      sinon.assert.calledOnce(server.ext);
+      sinon.assert.calledWithExactly(server.ext, sinon.match.string, sinon.match.func);
+
+      // call the server extension
+      const reply = sinon.stub();
+      const [,handler] = server.ext.firstCall.args;
+      handler({}, reply);
+
+      // ensure that the handler called reply and unregistered the time
+      sinon.assert.calledOnce(reply);
+      expect(getTimerCount()).to.be(0);
     });
 
     it('should set the cluster green if everything is ready', function () {

src/core_plugins/elasticsearch/lib/health_check.js

@@ -145,6 +145,11 @@ module.exports = function (plugin, server, { mappings }) {
     return true;
   }
 
+  server.ext('onPreStop', (request, reply) => {
+    stopChecking();
+    reply();
+  });
+
   return {
     waitUntilReady: waitUntilReady,
     run: check,