Implement health check service and global exception handling

backend/src/common/filters/global-exception.filter.ts

@@ -0,0 +1,82 @@
+import {
+  ExceptionFilter,
+  Catch,
+  ArgumentsHost,
+  HttpException,
+  HttpStatus,
+  Logger,
+} from '@nestjs/common';
+import { Response } from 'express';
+
+interface ErrorResponse {
+  statusCode: number;
+  message: string;
+  timestamp: string;
+  path?: string;
+}
+
+/**
+ * Global exception filter som formaterar alla errors konsistent
+ * Returnerar tydliga, svenska felmeddelanden utan att läcka känslig info
+ */
+@Catch()
+export class GlobalExceptionFilter implements ExceptionFilter {
+  private readonly logger = new Logger(GlobalExceptionFilter.name);
+
+  catch(exception: any, host: ArgumentsHost) {
+    const ctx = host.switchToHttp();
+    const response = ctx.getResponse<Response>();
+    const request = ctx.getRequest();
+    const path = request.url;
+
+    let statusCode = HttpStatus.INTERNAL_SERVER_ERROR;
+    let message = 'Ett internt serverfel inträffade.';
+
+    // Hantera HTTP-exceptions (t.ex. NotFoundException)
+    if (exception instanceof HttpException) {
+      statusCode = exception.getStatus();
+      const exceptionResponse = exception.getResponse();
+
+      if (typeof exceptionResponse === 'object' && 'message' in exceptionResponse) {
+        message = (exceptionResponse as any).message || message;
+      } else if (typeof exceptionResponse === 'string') {
+        message = exceptionResponse;
+      }
+    } else if (exception instanceof Error) {
+      // Hantera vanliga Error-instanser
+      message = exception.message || message;
+      statusCode = HttpStatus.BAD_REQUEST;
+
+      // Log interna fel för debugging
+      this.logger.error(`Error: ${exception.message}`, exception.stack);
+    }
+
+    // Säkerställ att felmeddelanden är användarvänliga (på svenska)
+    if (message.includes('Unknown unit')) {
+      message = 'Okänd enhet. Kontrollera enheten och försök igen.';
+    } else if (message.includes('Cannot convert between incompatible unit types')) {
+      message = 'Kan inte konvertera mellan dessa enhetstyper.';
+    } else if (message.includes('Inventory item with id') && message.includes('not found')) {
+      message = 'Hemmavarorna hittades inte.';
+    } else if (message.includes('Product with id') && message.includes('not found')) {
+      message = 'Produkten hittades inte.';
+    } else if (message.includes('Recipe with id') && message.includes('not found')) {
+      message = 'Receptet hittades inte.';
+    } else if (message.includes('sourceProductId och targetProductId kan inte vara samma')) {
+      message = 'Du kan inte slå samman en produkt med sig själv.';
+    }
+
+    const errorResponse: ErrorResponse = {
+      statusCode,
+      message,
+      timestamp: new Date().toISOString(),
+      path,
+    };
+
+    this.logger.warn(
+      `${request.method} ${path} - Status: ${statusCode}, Message: ${message}`,
+    );
+
+    response.status(statusCode).json(errorResponse);
+  }
+}

backend/src/health/health.controller.ts

@@ -1,36 +1,41 @@
-import { Controller, Get } from '@nestjs/common';
-import { PrismaService } from '../prisma/prisma.service';
+import { Controller, Get, HttpCode, Res } from '@nestjs/common';
+import { Response } from 'express';
+import { HealthService } from './health.service';
 
 @Controller('health')
 export class HealthController {
-  constructor(private readonly prisma: PrismaService) {}
+  constructor(private readonly healthService: HealthService) {}
 
+  /**
+   * Övergripande hälsostatus för tjänsten
+   * Returnerar 200 om allt är bra, 503 om något är fel
+   */
   @Get()
-  getHealth() {
-    return {
-      status: 'ok',
-      service: 'recipe-api',
-      timestamp: new Date().toISOString(),
-    };
+  async getHealth(@Res() res: Response) {
+    const health = await this.healthService.getOverallHealth();
+    res.status(health.statusCode).json({
+      status: health.status,
+      service: health.service,
+      timestamp: health.timestamp,
+      uptime: health.uptime,
+      checks: health.checks,
+    });
   }
 
+  /**
+   * Databasspecific hälsokontroll
+   * Returnerar 200 om databasen är tillgänglig, 503 om inte
+   */
   @Get('db')
-  async getDatabaseHealth() {
-    try {
-      await this.prisma.$queryRaw`SELECT 1`;
-
-      return {
-        status: 'ok',
-        database: 'connected',
-        timestamp: new Date().toISOString(),
-      };
-    } catch (error) {
-      return {
-        status: 'error',
-        database: 'not reachable',
-        message: error instanceof Error ? error.message : 'unknown error',
-        timestamp: new Date().toISOString(),
-      };
-    }
+  async getDatabaseHealth(@Res() res: Response) {
+    const dbHealth = await this.healthService.getDatabaseHealth();
+    res.status(dbHealth.statusCode).json({
+      status: dbHealth.status,
+      database: dbHealth.database,
+      responseTime: `${dbHealth.responseTime}ms`,
+      timestamp: dbHealth.timestamp,
+      details: dbHealth.details,
+    });
   }
 }
+

backend/src/health/health.module.ts

@@ -1,7 +1,11 @@
 import { Module } from '@nestjs/common';
 import { HealthController } from './health.controller';
+import { HealthService } from './health.service';
+import { PrismaModule } from '../prisma/prisma.module';
 
 @Module({
+  imports: [PrismaModule],
   controllers: [HealthController],
+  providers: [HealthService],
 })
 export class HealthModule {}

backend/src/health/health.service.ts

@@ -0,0 +1,116 @@
+import { Injectable } from '@nestjs/common';
+import { PrismaService } from '../prisma/prisma.service';
+
+export interface HealthStatus {
+  status: 'healthy' | 'degraded' | 'unhealthy';
+  service: string;
+  timestamp: string;
+  uptime: number;
+  checks: {
+    database: {
+      status: 'ok' | 'error';
+      responseTime: number;
+      details?: string;
+    };
+  };
+}
+
+@Injectable()
+export class HealthService {
+  private readonly startTime = Date.now();
+
+  constructor(private readonly prisma: PrismaService) {}
+
+  async getOverallHealth(): Promise<{
+    status: 'healthy' | 'degraded' | 'unhealthy';
+    statusCode: number;
+    service: string;
+    timestamp: string;
+    uptime: number;
+    checks: {
+      database: {
+        status: 'ok' | 'error';
+        responseTime: number;
+        details?: string;
+      };
+    };
+  }> {
+    const timestamp = new Date().toISOString();
+    const uptime = Date.now() - this.startTime;
+
+    // Testa databaskopplingen
+    const dbStart = Date.now();
+    let dbStatus: 'ok' | 'error' = 'ok';
+    let dbResponseTime = 0;
+    let dbDetails: string | undefined;
+
+    try {
+      await this.prisma.$queryRaw`SELECT 1`;
+      dbResponseTime = Date.now() - dbStart;
+    } catch (error) {
+      dbStatus = 'error';
+      dbResponseTime = Date.now() - dbStart;
+      dbDetails = error instanceof Error ? error.message : 'Unknown database error';
+    }
+
+    // Bestäm övergripande hälsa
+    let overallStatus: 'healthy' | 'degraded' | 'unhealthy' = 'healthy';
+    if (dbStatus === 'error') {
+      overallStatus = 'unhealthy';
+    }
+
+    const statusCode = overallStatus === 'unhealthy' ? 503 : 200;
+
+    return {
+      status: overallStatus,
+      statusCode,
+      service: 'recipe-api',
+      timestamp,
+      uptime,
+      checks: {
+        database: {
+          status: dbStatus,
+          responseTime: dbResponseTime,
+          details: dbDetails,
+        },
+      },
+    };
+  }
+
+  async getDatabaseHealth(): Promise<{
+    status: 'ok' | 'error';
+    database: string;
+    responseTime: number;
+    timestamp: string;
+    details?: string;
+    statusCode: number;
+  }> {
+    const timestamp = new Date().toISOString();
+    const startTime = Date.now();
+
+    try {
+      await this.prisma.$queryRaw`SELECT 1`;
+      const responseTime = Date.now() - startTime;
+
+      return {
+        status: 'ok',
+        database: 'connected',
+        responseTime,
+        timestamp,
+        statusCode: 200,
+      };
+    } catch (error) {
+      const responseTime = Date.now() - startTime;
+      const details = error instanceof Error ? error.message : 'Unknown database error';
+
+      return {
+        status: 'error',
+        database: 'not reachable',
+        responseTime,
+        timestamp,
+        details,
+        statusCode: 503,
+      };
+    }
+  }
+}

backend/src/main.ts

@@ -1,11 +1,16 @@
 import { ValidationPipe } from '@nestjs/common';
 import { NestFactory } from '@nestjs/core';
 import { AppModule } from './app.module';
+import { GlobalExceptionFilter } from './common/filters/global-exception.filter';
 
 async function bootstrap() {
   const app = await NestFactory.create(AppModule);
 
   app.setGlobalPrefix('api');
+  
+  // Registrera global exception filter
+  app.useGlobalFilters(new GlobalExceptionFilter());
+  
   app.useGlobalPipes(
     new ValidationPipe({
       whitelist: true,