Context and Problem
Modern applications often need to direct traffic to multiple backend services based on request attributes.
- Direct client access to multiple services increases complexity.
- Managing different versions of APIs leads to routing challenges.
- Handling blue-green deployments or canary releases requires dynamic routing.
- Security concerns arise when exposing backend services directly.
Solution
The Gateway Routing pattern directs requests to appropriate backend services based on request attributes.
- Define routing rules in an API gateway.
- Use request headers, query parameters, or paths for routing decisions.
- Implement traffic splitting for gradual rollouts.
- Secure requests by enforcing authentication at the gateway.
- Monitor and log routing behavior for analytics.
Benefits
- Simplified client access
- Clients interact with a single gateway instead of multiple services.
- Versioning support
- Routes traffic to different API versions seamlessly.
- Deployment flexibility
- Enables blue-green and canary deployments.
- Enhanced security
- Prevents direct exposure of backend services.
Trade-offs
- Configuration complexity
- Requires proper setup of routing rules and policies.
- Performance overhead
- Routing logic may introduce slight latency.
- Dependency on gateway
- All requests must pass through the gateway.
Issues and Considerations
- Route misconfiguration
- Incorrect rules can lead to traffic misdirection.
- Performance bottlenecks
- Improper gateway scaling can impact responsiveness.
- API versioning strategy
- Managing multiple versions efficiently.
When to Use This Pattern
- When directing traffic to multiple backend services dynamically.
- When implementing blue-green or canary deployments.
- When needing to enforce API versioning policies.