add error management for failed Validation Pipes (#169)

* add error management for failed Validation Pipes

* format

* test exception on ping controller

* registered exception filters to policy-engine

* format

* Update apps/armory/src/shared/filter/application-exception.filter.ts

Co-authored-by: William Calderipe <wcalderipe@gmail.com>

* ported filter test file

---------

Co-authored-by: William Calderipe <wcalderipe@gmail.com>

apps/armory/src/main.ts

@@ -6,6 +6,7 @@ import { lastValueFrom, map, of, switchMap } from 'rxjs'
 import { Config } from './armory.config'
 import { ArmoryModule } from './armory.module'
 import { ApplicationExceptionFilter } from './shared/filter/application-exception.filter'
+import { HttpExceptionFilter } from './shared/filter/http-exception.filter'
 import { ZodExceptionFilter } from './shared/filter/zod-exception.filter'
 
 /**
@@ -64,7 +65,11 @@ const withGlobalInterceptors = (app: INestApplication): INestApplication => {
 const withGlobalFilters =
   (configService: ConfigService<Config, true>) =>
   (app: INestApplication): INestApplication => {
-    app.useGlobalFilters(new ApplicationExceptionFilter(configService), new ZodExceptionFilter(configService))
+    app.useGlobalFilters(
+      new ApplicationExceptionFilter(configService),
+      new ZodExceptionFilter(configService),
+      new HttpExceptionFilter(configService)
+    )
 
     return app
   }

apps/armory/src/shared/filter/http-exception.filter.ts

@@ -0,0 +1,36 @@
+import { ArgumentsHost, Catch, ExceptionFilter, HttpException, Logger } from '@nestjs/common'
+import { ConfigService } from '@nestjs/config'
+import { Response } from 'express'
+import { Config, Env } from '../../armory.config'
+
+@Catch(HttpException)
+export class HttpExceptionFilter implements ExceptionFilter {
+  private logger = new Logger(HttpExceptionFilter.name)
+
+  constructor(private configService: ConfigService<Config, true>) {}
+
+  catch(exception: HttpException, host: ArgumentsHost) {
+    const ctx = host.switchToHttp()
+    const response = ctx.getResponse<Response>()
+    const status = exception.getStatus()
+
+    const isProduction = this.configService.get('env') === Env.PRODUCTION
+
+    this.logger.error(exception)
+
+    response.status(status).json(
+      isProduction
+        ? {
+            statusCode: status,
+            message: exception.message,
+            response: exception.getResponse()
+          }
+        : {
+            statusCode: status,
+            message: exception.message,
+            response: exception.getResponse(),
+            stack: exception.stack
+          }
+    )
+  }
+}

apps/policy-engine/src/engine/app.controller.ts

@@ -20,7 +20,6 @@ export class AppController {
     this.logger.log({
       message: 'Received ping'
     })
-
     return 'pong'
   }
 

apps/policy-engine/src/main.ts

@@ -3,7 +3,10 @@ import { ConfigService } from '@nestjs/config'
 import { NestFactory } from '@nestjs/core'
 import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger'
 import { lastValueFrom, map, of, switchMap } from 'rxjs'
+import { Config } from './policy-engine.config'
 import { PolicyEngineModule } from './policy-engine.module'
+import { ApplicationExceptionFilter } from './shared/filter/application-exception.filter'
+import { HttpExceptionFilter } from './shared/filter/http-exception.filter'
 
 /**
  * Adds Swagger documentation to the application.
@@ -37,6 +40,21 @@ const withGlobalPipes = (app: INestApplication): INestApplication => {
   return app
 }
 
+/**
+ * Adds a global exception filter to the application.
+ *
+ * @param app - The Nest application instance.
+ * @param configService - The configuration service instance.
+ * @returns The modified Nest application instance.
+ */
+const withGlobalFilters =
+  (configService: ConfigService<Config, true>) =>
+  (app: INestApplication): INestApplication => {
+    app.useGlobalFilters(new HttpExceptionFilter(configService), new ApplicationExceptionFilter(configService))
+
+    return app
+  }
+
 async function bootstrap() {
   const logger = new Logger('PolicyEngineBootstrap')
   const application = await NestFactory.create(PolicyEngineModule, { bodyParser: true })
@@ -51,6 +69,7 @@ async function bootstrap() {
     of(application).pipe(
       map(withSwagger),
       map(withGlobalPipes),
+      map(withGlobalFilters(configService)),
       switchMap((app) => app.listen(port))
     )
   )

apps/policy-engine/src/shared/filter/__test__/unit/application-exception.filter.spec.ts

@@ -0,0 +1,82 @@
+import { ArgumentsHost, HttpStatus } from '@nestjs/common'
+import { HttpArgumentsHost } from '@nestjs/common/interfaces'
+import { ConfigService } from '@nestjs/config'
+import { Response } from 'express'
+import { mock } from 'jest-mock-extended'
+import { Config, Env } from '../../../../policy-engine.config'
+import { ApplicationException } from '../../../exception/application.exception'
+import { ApplicationExceptionFilter } from '../../application-exception.filter'
+
+describe(ApplicationExceptionFilter.name, () => {
+  const exception = new ApplicationException({
+    message: 'Test application exception filter',
+    suggestedHttpStatusCode: HttpStatus.INTERNAL_SERVER_ERROR,
+    context: {
+      additional: 'information',
+      to: 'debug'
+    }
+  })
+
+  const buildArgumentsHostMock = (): [ArgumentsHost, jest.Mock, jest.Mock] => {
+    const jsonMock = jest.fn()
+    const statusMock = jest.fn().mockReturnValue(
+      mock<Response>({
+        json: jsonMock
+      })
+    )
+
+    const host = mock<ArgumentsHost>({
+      switchToHttp: jest.fn().mockReturnValue(
+        mock<HttpArgumentsHost>({
+          getResponse: jest.fn().mockReturnValue(
+            mock<Response>({
+              status: statusMock
+            })
+          )
+        })
+      )
+    })
+
+    return [host, statusMock, jsonMock]
+  }
+
+  const buildConfigServiceMock = (env: Env) =>
+    mock<ConfigService<Config, true>>({
+      get: jest.fn().mockReturnValue(env)
+    })
+
+  describe('catch', () => {
+    describe('when environment is production', () => {
+      it('responds with exception status and short message', () => {
+        const filter = new ApplicationExceptionFilter(buildConfigServiceMock(Env.PRODUCTION))
+        const [host, statusMock, jsonMock] = buildArgumentsHostMock()
+
+        filter.catch(exception, host)
+
+        expect(statusMock).toHaveBeenCalledWith(exception.getStatus())
+        expect(jsonMock).toHaveBeenCalledWith({
+          statusCode: exception.getStatus(),
+          message: exception.message,
+          context: exception.context
+        })
+      })
+    })
+
+    describe('when environment is not production', () => {
+      it('responds with exception status and complete message', () => {
+        const filter = new ApplicationExceptionFilter(buildConfigServiceMock(Env.DEVELOPMENT))
+        const [host, statusMock, jsonMock] = buildArgumentsHostMock()
+
+        filter.catch(exception, host)
+
+        expect(statusMock).toHaveBeenCalledWith(exception.getStatus())
+        expect(jsonMock).toHaveBeenCalledWith({
+          statusCode: exception.getStatus(),
+          message: exception.message,
+          context: exception.context,
+          stack: exception.stack
+        })
+      })
+    })
+  })
+})

apps/policy-engine/src/shared/filter/application-exception.filter.ts

@@ -0,0 +1,52 @@
+import { ArgumentsHost, Catch, ExceptionFilter, LogLevel, Logger } from '@nestjs/common'
+import { ConfigService } from '@nestjs/config'
+import { Response } from 'express'
+import { Config, Env } from '../../policy-engine.config'
+import { ApplicationException } from '../../shared/exception/application.exception'
+
+@Catch(ApplicationException)
+export class ApplicationExceptionFilter implements ExceptionFilter {
+  private logger = new Logger(ApplicationExceptionFilter.name)
+
+  constructor(private configService: ConfigService<Config, true>) {}
+
+  catch(exception: ApplicationException, host: ArgumentsHost) {
+    const ctx = host.switchToHttp()
+    const response = ctx.getResponse<Response>()
+    const status = exception.getStatus()
+    const isProduction = this.configService.get('env') === Env.PRODUCTION
+
+    this.log(exception)
+
+    response.status(status).json(
+      isProduction
+        ? {
+            statusCode: status,
+            message: exception.message,
+            context: exception.context
+          }
+        : {
+            statusCode: status,
+            message: exception.message,
+            context: exception.context,
+            stack: exception.stack,
+            ...(exception.origin && { origin: exception.origin })
+          }
+    )
+  }
+
+  // TODO (@wcalderipe, 16/01/24): Unit test the logging logic. For that, we
+  // must inject the logger in the constructor via dependency injection.
+  private log(exception: ApplicationException) {
+    const level: LogLevel = exception.getStatus() >= 500 ? 'error' : 'warn'
+
+    if (this.logger[level]) {
+      this.logger[level](exception.message, {
+        status: exception.getStatus(),
+        context: exception.context,
+        stacktrace: exception.stack,
+        origin: exception.origin
+      })
+    }
+  }
+}

apps/policy-engine/src/shared/filter/http-exception.filter.ts

@@ -0,0 +1,41 @@
+import { ArgumentsHost, Catch, ExceptionFilter, HttpException, Logger } from '@nestjs/common'
+import { ConfigService } from '@nestjs/config'
+import { Response } from 'express'
+import { Config, Env } from '../../policy-engine.config'
+
+@Catch(HttpException)
+export class HttpExceptionFilter implements ExceptionFilter {
+  private logger = new Logger(HttpExceptionFilter.name)
+
+  constructor(private configService: ConfigService<Config, true>) {}
+
+  catch(exception: HttpException, host: ArgumentsHost) {
+    const ctx = host.switchToHttp()
+    const response = ctx.getResponse<Response>()
+    const status = exception.getStatus()
+
+    const isProduction = this.configService.get('env') === Env.PRODUCTION
+
+    this.logger.error({
+      message: exception.message,
+      stack: exception.stack,
+      response: exception.getResponse(),
+      statusCode: status
+    })
+
+    response.status(status).json(
+      isProduction
+        ? {
+            statusCode: status,
+            message: exception.message,
+            response: exception.getResponse()
+          }
+        : {
+            statusCode: status,
+            message: exception.message,
+            response: exception.getResponse(),
+            stack: exception.stack
+          }
+    )
+  }
+}