88 lines
3.8 KiB
Markdown
88 lines
3.8 KiB
Markdown
# ADR-0029: Microservices Architecture
|
|
|
|
## Status
|
|
Accepted
|
|
|
|
## Context
|
|
The platform needs to scale independently, support team autonomy, and enable flexible deployment. A microservices architecture provides these benefits from day one, and the complexity of supporting both monolith and microservices modes is unnecessary.
|
|
|
|
## Decision
|
|
Design the platform as **microservices architecture from day one**:
|
|
|
|
1. **Service-Based Architecture**: All modules are independent services:
|
|
- Each module is a separate service with its own process
|
|
- Services communicate via gRPC (primary) or HTTP (fallback)
|
|
- Service client interfaces for all inter-service communication
|
|
- No direct in-process calls between services
|
|
|
|
2. **Service Registry**: Central registry for service discovery:
|
|
- All services register on startup
|
|
- Service discovery via registry
|
|
- Health checking and automatic deregistration
|
|
- Support for Consul, etcd, or Kubernetes service discovery
|
|
|
|
3. **Communication Patterns**:
|
|
- **Synchronous**: gRPC service calls (primary), HTTP/REST (fallback)
|
|
- **Asynchronous**: Event bus via Kafka
|
|
- **Shared State**: Cache (Redis) and Database (PostgreSQL)
|
|
|
|
4. **Service Boundaries**: Each module is an independent service:
|
|
- Independent Go modules (`go.mod`)
|
|
- Own database schema (via Ent)
|
|
- Own API routes
|
|
- Own process and deployment
|
|
- Can be scaled independently
|
|
|
|
5. **Development Simplification**: For local development, multiple services can run in the same process, but they still communicate via service clients (no direct calls)
|
|
|
|
## Consequences
|
|
|
|
### Positive
|
|
- **Simplified Architecture**: Single architecture pattern, no dual-mode complexity
|
|
- **Independent Scaling**: Scale individual services based on load
|
|
- **Team Autonomy**: Teams can own and deploy their services independently
|
|
- **Technology Diversity**: Different services can use different tech stacks (future)
|
|
- **Fault Isolation**: Failure in one service doesn't bring down entire platform
|
|
- **Deployment Flexibility**: Deploy services independently
|
|
- **Clear Boundaries**: Service boundaries are explicit from the start
|
|
|
|
### Negative
|
|
- **Network Latency**: Inter-service calls have network overhead
|
|
- **Distributed System Challenges**: Need to handle network failures, retries, timeouts
|
|
- **Service Discovery Overhead**: Additional infrastructure needed
|
|
- **Debugging Complexity**: Distributed tracing becomes essential
|
|
- **Data Consistency**: Cross-service transactions become challenging
|
|
- **Development Setup**: More complex local development (multiple services)
|
|
|
|
### Mitigations
|
|
- **Service Mesh**: Use service mesh (Istio, Linkerd) for advanced microservices features
|
|
- **API Gateway**: Central gateway for routing and cross-cutting concerns
|
|
- **Event Sourcing**: Use events for eventual consistency
|
|
- **Circuit Breakers**: Implement circuit breakers for resilience
|
|
- **Comprehensive Observability**: OpenTelemetry, metrics, logging essential
|
|
- **Docker Compose**: Simplify local development with docker-compose
|
|
- **Development Mode**: Run multiple services in same process for local dev (still use service clients)
|
|
|
|
## Implementation Strategy
|
|
|
|
### Epic 1: Service Client Interfaces (Epic 1)
|
|
- Define service client interfaces for all core services
|
|
- All inter-service communication goes through interfaces
|
|
|
|
### Epic 2: Service Registry (Epic 3)
|
|
- Create service registry interface
|
|
- Implement service discovery
|
|
- Support for Consul, Kubernetes service discovery
|
|
|
|
### Epic 3: gRPC Services (Epic 5)
|
|
- Implement gRPC service definitions
|
|
- Create gRPC servers for all services
|
|
- Create gRPC clients for service communication
|
|
- HTTP clients as fallback option
|
|
|
|
## References
|
|
- [Service Abstraction Pattern](https://microservices.io/patterns/data/service-per-database.html)
|
|
- [Service Discovery Patterns](https://microservices.io/patterns/service-registry.html)
|
|
- [gRPC Documentation](https://grpc.io/docs/)
|
|
|