Enhance health check code

posts/cucumber-with-typescript/tsconfig.json

@@ -22,7 +22,7 @@
     "strict": true,                           /* Enable all strict type-checking options. */
     "noImplicitAny": true,                    /* Raise error on expressions and declarations with an implied 'any' type. */
     "strictNullChecks": true,                 /* Enable strict null checks. */
-    // "strictFunctionTypes": true,           /* Enable strict checking of function types. */
+    // "strictFunctionTypes": true,           /* Enable strict checking of function enums. */
     // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */
     // "noImplicitThis": true,                /* Raise error on 'this' expressions with an implied 'any' type. */
     // "alwaysStrict": true,                  /* Parse in strict mode and emit "use strict" for each source file. */
@@ -39,7 +39,7 @@
     // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
     // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
     // "typeRoots": [],                       /* List of folders to include type definitions from. */
-    // "types": [],                           /* Type declaration files to be included in compilation. */
+    // "enums": [],                           /* Type declaration files to be included in compilation. */
     // "allowSyntheticDefaultImports": true,  /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
     "esModuleInterop": true,                  /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
     // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */

posts/standardized-health-checks/enums/resource-health.enum.ts

@@ -0,0 +1,4 @@
+export enum ResourceHealth {
+  'HEALTHY',
+  'UNHEALTHY'
+}

posts/standardized-health-checks/health/health-indicator.ts

@@ -1,8 +1,8 @@
-import { ResourceHealth } from '../types/resource-health.type';
+import { ResourceHealth } from '../enums/resource-health.enum';
 
 export abstract class HealthIndicator {
   abstract name: string;
-  status: ResourceHealth = 'UNHEALTHY';
+  status: ResourceHealth = ResourceHealth.UNHEALTHY;
   details: string | undefined;
 
   abstract checkHealth(): Promise<void>;

posts/standardized-health-checks/health/some-service.check.ts

@@ -1,5 +1,6 @@
 import axios, { AxiosResponse } from 'axios';
 import { HealthIndicator } from './health-indicator';
+import { ResourceHealth } from '../enums/resource-health.enum';
 
 export class SomeServiceCheck extends HealthIndicator {
   name: string = 'Some Service';
@@ -11,13 +12,13 @@ export class SomeServiceCheck extends HealthIndicator {
       result = await axios(pingURL);
 
       if (result.status === 200) {
-        this.status = 'HEALTHY';
+        this.status = ResourceHealth.HEALTHY;
       } else {
-        this.status = 'UNHEALTHY';
+        this.status = ResourceHealth.UNHEALTHY;
         this.details = `Received status: ${result.status}`;
       }
     } catch (e) {
-      this.status = 'UNHEALTHY';
+      this.status = ResourceHealth.UNHEALTHY;
       this.details = e.message;
       console.log(`HEALTH: ${this.name} is unhealthy.`, e.message);
     }

posts/standardized-health-checks/routes/health.routes.ts

@@ -1,6 +1,7 @@
 import { SomeServiceCheck } from '../health/some-service.check';
 import { HealthService } from '../services/health-service';
 import { Router } from 'express';
+import { ResourceHealth } from '../enums/resource-health.enum';
 
 const healthRoutes = Router();
 
@@ -14,7 +15,7 @@ healthRoutes.get('/health', async (req, res) => {
 
   const healthResults = await healthService.getHealth();
 
-  res.status(healthResults.status === 'HEALTHY' ? 200 : 503)
+  res.status(healthResults.status === ResourceHealth.HEALTHY ? 200 : 503)
     .send({
       status: healthResults.status, dependencies: healthResults.results
     });

posts/standardized-health-checks/services/health-service.ts

@@ -1,28 +1,26 @@
 import { HealthIndicator } from '../health/health-indicator';
-import { ResourceHealth } from '../types/resource-health.type';
+import { ResourceHealth } from '../enums/resource-health.enum';
 
 export class HealthService {
   private readonly checks: HealthIndicator[];
-  public overallHealth: ResourceHealth = 'HEALTHY';
+  public overallHealth: ResourceHealth = ResourceHealth.HEALTHY;
 
   constructor(checks: HealthIndicator[]) {
     this.checks = checks;
   }
 
   async getHealth(): Promise<HealthCheckResult> {
     await Promise.all(
-      this.checks.map((check) => {
-          return check.checkHealth();
-        }
-      )
+      this.checks.map(check => check.checkHealth())
+    );
+
+    const anyUnhealthy = this.checks.some(item =>
+      item.status === ResourceHealth.UNHEALTHY
     );
 
-    const anyUnhealthy = this.checks.some((item) => {
-      return item.status === 'UNHEALTHY';
-    });
     this.overallHealth = anyUnhealthy
-      ? 'UNHEALTHY'
-      : 'HEALTHY';
+      ? ResourceHealth.UNHEALTHY
+      : ResourceHealth.HEALTHY;
 
     return {
       status: this.overallHealth,

posts/standardized-health-checks/tests/health-check.integration.test.ts

@@ -1,10 +1,11 @@
 import axios from 'axios';
+import { ResourceHealth } from '../enums/resource-health.enum';
 
 // Service MUST be running!
 describe('Health Checks - Integration', () => {
   it('should return healthy if all downstream dependencies are healthy', async () => {
     const result = await axios.get('http://localhost:8080/health');
     expect(result.status).toBe(200);
-    expect(result.data.dependencies[0].status).toEqual('HEALTHY');
+    expect(result.data.dependencies[0].status).toEqual(ResourceHealth.HEALTHY);
   });
 });

posts/standardized-health-checks/tests/health-check.test.ts

@@ -1,6 +1,7 @@
 import { HealthService } from '../services/health-service';
 import { MockIndicator } from './mocks/mock-indicator';
 import { MockToggleIndicator } from './mocks/mock-toggle-indicator';
+import { ResourceHealth } from '../enums/resource-health.enum';
 
 describe('Health Checks', () => {
   describe('Health Service', () => {
@@ -11,33 +12,33 @@ describe('Health Checks', () => {
 
       const result = await service.getHealth();
 
-      expect(result.status).toEqual('HEALTHY');
-      expect(result.results[0].status).toEqual('HEALTHY');
+      expect(result.status).toEqual(ResourceHealth.HEALTHY);
+      expect(result.results[0].status).toEqual(ResourceHealth.HEALTHY);
       expect(result.results[0].details).not.toBeDefined()
     });
 
     it('should evaluate health - unhealthy', async () => {
       const service = new HealthService([
-        new MockIndicator('UNHEALTHY')
+        new MockIndicator(ResourceHealth.UNHEALTHY)
       ]);
 
       const result = await service.getHealth();
 
-      expect(result.status).toEqual('UNHEALTHY');
-      expect(result.results[0].status).toEqual('UNHEALTHY');
+      expect(result.status).toEqual(ResourceHealth.UNHEALTHY);
+      expect(result.results[0].status).toEqual(ResourceHealth.UNHEALTHY);
     });
 
     it('should evaluate unhealthy if mixed health dependencies', async () => {
       const service = new HealthService([
         new MockIndicator(),
-        new MockIndicator('UNHEALTHY')
+        new MockIndicator(ResourceHealth.UNHEALTHY)
       ]);
 
       const result = await service.getHealth();
 
-      expect(result.status).toEqual('UNHEALTHY');
-      expect(result.results.filter((result) => result.status === 'HEALTHY').length).toBe(1);
-      expect(result.results.filter((result) => result.status === 'UNHEALTHY').length).toBe(1);
+      expect(result.status).toEqual(ResourceHealth.UNHEALTHY);
+      expect(result.results.filter((result) => result.status === ResourceHealth.HEALTHY).length).toBe(1);
+      expect(result.results.filter((result) => result.status === ResourceHealth.UNHEALTHY).length).toBe(1);
     });
 
     it('should be able to return to healthy after being unhealthy', async () => {
@@ -46,20 +47,20 @@ describe('Health Checks', () => {
       ]);
 
       let result = await service.getHealth();
-      expect(result.status).toEqual('UNHEALTHY');
+      expect(result.status).toEqual(ResourceHealth.UNHEALTHY);
 
       result = await service.getHealth();
-      expect(result.status).toEqual('HEALTHY');
+      expect(result.status).toEqual(ResourceHealth.HEALTHY);
     });
 
     it('should return details when unhealthy', async () => {
       const unhealthyDetails = 'Unable to communicate to DB';
       const service = new HealthService([
-        new MockIndicator('UNHEALTHY', unhealthyDetails),
+        new MockIndicator(ResourceHealth.UNHEALTHY, unhealthyDetails),
       ]);
 
       let result = await service.getHealth();
-      expect(result.status).toEqual('UNHEALTHY');
+      expect(result.status).toEqual(ResourceHealth.UNHEALTHY);
       expect(result.results[0].details).toEqual(unhealthyDetails);
     });
   });

posts/standardized-health-checks/tests/mocks/mock-indicator.ts

@@ -1,12 +1,12 @@
 import { HealthIndicator } from '../../health/health-indicator';
-import { ResourceHealth } from '../../types/resource-health.type';
+import { ResourceHealth } from '../../enums/resource-health.enum';
 
 export class MockIndicator extends HealthIndicator {
   name = 'Mock Indicator';
 
   constructor(health?: ResourceHealth, details?: string) {
     super();
-    this.status = health || 'HEALTHY';
+    this.status = health || ResourceHealth.HEALTHY;
     if (details) {
       this.details = details;
     }

posts/standardized-health-checks/tests/mocks/mock-toggle-indicator.ts

@@ -1,21 +1,21 @@
 import { HealthIndicator } from '../../health/health-indicator';
-import { ResourceHealth } from '../../types/resource-health.type';
+import { ResourceHealth } from '../../enums/resource-health.enum';
 
 export class MockToggleIndicator extends HealthIndicator {
   name = 'Mock Toggle Indicator';
 
   constructor(health?: ResourceHealth) {
     super();
-    this.status = health || 'HEALTHY';
+    this.status = health || ResourceHealth.HEALTHY;
   }
 
   checkHealth(): Promise<void> {
-    this.status = this.status === 'HEALTHY'
-      ? 'UNHEALTHY'
-      : 'HEALTHY';
+    this.status = this.status === ResourceHealth.HEALTHY
+      ? ResourceHealth.UNHEALTHY
+      : ResourceHealth.HEALTHY;
 
     return new Promise((resolve) => {
       resolve();
     });
   }
-}
+}

posts/standardized-health-checks/tsconfig.json

@@ -22,7 +22,7 @@
     "strict": true,                           /* Enable all strict type-checking options. */
     "noImplicitAny": true,                    /* Raise error on expressions and declarations with an implied 'any' type. */
     "strictNullChecks": true   ,              /* Enable strict null checks. */
-    // "strictFunctionTypes": true,           /* Enable strict checking of function types. */
+    // "strictFunctionTypes": true,           /* Enable strict checking of function enums. */
     // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */
     // "noImplicitThis": true,                /* Raise error on 'this' expressions with an implied 'any' type. */
     // "alwaysStrict": true,                  /* Parse in strict mode and emit "use strict" for each source file. */
@@ -39,7 +39,7 @@
     // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
     // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
     // "typeRoots": [],                       /* List of folders to include type definitions from. */
-    // "types": [],                           /* Type declaration files to be included in compilation. */
+    // "enums": [],                           /* Type declaration files to be included in compilation. */
     // "allowSyntheticDefaultImports": true,  /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
     "esModuleInterop": true                   /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
     // "preserveSymlinks": true,              /* Do not resolve the real path of symlinks. */