feat: Health check methods (#308) Thanks to @willhausman!

* started adding testConnections

* functions for testing and releasing all current active drivers

* call core functions from server

* redundant async

* null checks

* resolved missing mock

packages/cubejs-server-core/core/OrchestratorApi.js

@@ -7,6 +7,9 @@ class OrchestratorApi {
   constructor(driverFactory, logger, options) {
     options = options || {};
     this.orchestrator = new QueryOrchestrator(options.redisPrefix || 'STANDALONE', driverFactory, logger, options);
+    this.driverFactory = driverFactory;
+    const { externalDriverFactory } = options;
+    this.externalDriverFactory = externalDriverFactory;
     this.logger = logger;
   }
 
@@ -57,6 +60,36 @@ class OrchestratorApi {
       throw { error: err.toString() };
     }
   }
+
+  testConnection() {
+    return Promise.all([
+      this.testDriverConnection(this.driverFactory),
+      this.testDriverConnection(this.externalDriverFactory)
+    ]);
+  }
+
+  async testDriverConnection(driverFn) {
+    if (driverFn) {
+      const driver = await driverFn();
+      await driver.testConnection();
+    }
+  }
+
+  release() {
+    return Promise.all([
+      this.releaseDriver(this.driverFactory),
+      this.releaseDriver(this.externalDriverFactory)
+    ]);
+  }
+
+  async releaseDriver(driverFn) {
+    if (driverFn) {
+      const driver = await driverFn();
+      if (driver.release) {
+        await driver.release();
+      }
+    }
+  }
 }
 
 module.exports = OrchestratorApi;

packages/cubejs-server-core/core/index.js

@@ -383,6 +383,25 @@ class CubejsServerCore {
     }
     return DriverDependencies[dbType];
   }
+
+  testConnections() {
+    const tests = [];
+    Object.keys(this.dataSourceIdToOrchestratorApi).forEach(dataSourceId => {
+      const orchestratorApi = this.dataSourceIdToOrchestratorApi[dataSourceId];
+      tests.push(orchestratorApi.testConnection());
+    });
+    return Promise.all(tests);
+  }
+
+  async releaseConnections() {
+    const releases = [];
+    Object.keys(this.dataSourceIdToOrchestratorApi).forEach(dataSourceId => {
+      const orchestratorApi = this.dataSourceIdToOrchestratorApi[dataSourceId];
+      releases.push(orchestratorApi.release());
+    });
+    await Promise.all(releases);
+    this.dataSourceIdToOrchestratorApi = {};
+  }
 }
 
 module.exports = CubejsServerCore;

packages/cubejs-server/index.js

@@ -83,6 +83,10 @@ class CubejsServer {
     }
   }
 
+  testConnections() {
+    return this.core.testConnections();
+  }
+
   async close() {
     try {
       if (this.socketServer) {
@@ -97,6 +101,7 @@ class CubejsServer {
         await this.redirector.close();
         this.redirector = null;
       }
+      await this.core.releaseConnections();
     } catch (e) {
       if (this.core.event) {
         await this.core.event("Dev Server Fatal Error", {

packages/cubejs-server/index.test.js

@@ -2,6 +2,7 @@ jest.mock("@cubejs-backend/server-core", () => {
   const staticCreate = jest.fn();
   const initApp = jest.fn(() => Promise.resolve())
   const event = jest.fn(() => Promise.resolve())
+  const releaseConnections = jest.fn(() => Promise.resolve())
   class CubejsServerCore {
     static create() {
       staticCreate.call(null, arguments);
@@ -14,11 +15,16 @@ jest.mock("@cubejs-backend/server-core", () => {
     event() {
       return event();
     }
+
+    releaseConnections() {
+      return releaseConnections();
+    }
   }
   CubejsServerCore.mock = {
     staticCreate,
     initApp,
     event,
+    releaseConnections,
   };
   return CubejsServerCore;
 });