EShop Microservices

Educational project to improve skills in microservice architectures.

Tech focus: ASP.NET Web API, Docker, RabbitMQ, MassTransit, gRPC, YARP API Gateway, PostgreSQL, Redis, SQLite, SQL Server, Marten, Entity Framework Core, CQRS, MediatR, DDD, Vertical Architecture, Clean Architecture, .NET 8, cloud-native environments, Carter, FluentValidation, Mapster.

---

Architecture

Microservices-based backend with centralized OpenTelemetry-based observability.

Application Services

Shopping.Web
        |
        v
Gateway
        |
        v
Basket.API  --gRPC-->  Discount.Grpc
        |
        +--RabbitMQ--> Ordering.API

Catalog.API (independent service)

All services export telemetry via OTLP to OpenTelemetry Collector. Collector routes data to Tempo, Loki and Prometheus. Grafana visualizes.

Communication

From	To	Protocol	Type
Web	Gateway	HTTP	Synchronous
Gateway	APIs	HTTP	Synchronous
Basket.API	Discount.Grpc	gRPC	Synchronous
Basket.API	Ordering.API	RabbitMQ	Asynchronous

Endpoints

Service	URL
Gateway	http://localhost:5000
Basket.API	http://localhost:5001
Catalog.API	http://localhost:5002
Ordering.API	http://localhost:5003
Discount.Grpc	http://localhost:5004

---

Services

Basket.API

• ASP.NET Core Web API\
• Carter\
• MediatR\
• FluentValidation\
• Marten (PostgreSQL)\
• Redis\
• gRPC client\
• MassTransit (RabbitMQ)\
• HealthChecks

Ordering.API

• ASP.NET Core Web API\
• Carter\
• MediatR\
• EF Core\
• SQL Server\
• MassTransit\
• HealthChecks

Catalog.API

• ASP.NET Core Web API\
• Carter\
• MediatR\
• Marten (PostgreSQL)\
• HealthChecks

Discount.Grpc

• ASP.NET Core gRPC\
• EF Core\
• PostgreSQL

Gateway (YARP)

• ASP.NET Core\
• YARP Reverse Proxy

Shopping.Web

• ASP.NET Core MVC / Razor\
• HttpClient -> Gateway

---

Observability

Centralized via OpenTelemetry.

All services export telemetry using:

OTLP (gRPC)
Otlp:Endpoint = http://otel-collector:4317

Tracing

• ASP.NET Core instrumentation\
• HttpClient instrumentation\
• MassTransit activity source\
• Database instrumentation (Npgsql / SqlClient)\
• Redis instrumentation

Metrics

• ASP.NET Core\
• HttpClient\
• Runtime metrics\
• Prometheus scrape via Collector (:8889)

Logging

• OpenTelemetry logging provider\
• Exported via OTLP to Collector\
• Routed to Loki

Stack

Located in:

/observability

Includes:

• OpenTelemetry Collector\
• Tempo\
• Loki\
• Prometheus\
• Grafana

Endpoints

Component	URL
Grafana	http://localhost:3000
Prometheus	http://localhost:9090
Tempo	http://localhost:3200
Loki	http://localhost:3100

Ports may vary depending on docker-compose configuration.

Grafana default credentials: admin / admin

---

Running

From project root:

./bootstrap.sh