Fault Injection

FastGateway supports fault injection to test service resilience and failure handling.

Non-Production Only

Fault injection should only be used in testing and staging environments. Never enable fault injection in production.

Delay Injection

Inject latency to test timeout handling:

filters:
  - type: "HTTPFaultInjection"
    faultInjection:
      delay:
        fixedDelay: "5s"
        percentage: 50

This adds a 5-second delay to 50% of requests.

Abort Injection

Inject errors to test failure handling:

filters:
  - type: "HTTPFaultInjection"
    faultInjection:
      abort:
        httpStatus: 503
        percentage: 10

This returns a 503 error for 10% of requests.

Combined Fault Injection

Inject both delays and aborts:

filters:
  - type: "HTTPFaultInjection"
    faultInjection:
      delay:
        fixedDelay: "2s"
        percentage: 30
      abort:
        httpStatus: 500
        percentage: 5

Configuration Options

Option	Description
fixedDelay	Duration of injected delay
httpStatus	HTTP status code for aborts
percentage	Percentage of requests affected (0-100)

Testing Scenarios

• Circuit breaker testing: Inject 503 errors to trigger circuit breakers
• Timeout validation: Inject delays longer than configured timeouts
• Retry logic testing: Inject intermittent failures
• Graceful degradation: Verify fallback behavior under failures

Best Practices

• Start with low percentages (1-5%)
• Use specific route matches to target specific endpoints
• Monitor metrics during fault injection tests
• Document expected behavior before testing