The FallbackHeaders
GatewayFilter
Factory
The FallbackHeaders
factory lets you add Hystrix or Spring Cloud CircuitBreaker execution exception details in the headers of a request forwarded to a fallbackUri
in an external application, as in the following scenario:
spring:
cloud:
gateway:
routes:
- id: ingredients
uri: lb://ingredients
predicates:
- Path=//ingredients/**
filters:
- name: CircuitBreaker
args:
name: fetchIngredients
fallbackUri: forward:/fallback
- id: ingredients-fallback
uri: http://localhost:9994
predicates:
- Path=/fallback
filters:
- name: FallbackHeaders
args:
executionExceptionTypeHeaderName: Test-Header
In this example, after an execution exception occurs while running the circuit breaker, the request is forwarded to the fallback
endpoint or handler in an application running on localhost:9994
.
The headers with the exception type, message and (if available) root cause exception type and message are added to that request by the FallbackHeaders
filter.
You can overwrite the names of the headers in the configuration by setting the values of the following arguments (shown with their default values):
-
executionExceptionTypeHeaderName
("Execution-Exception-Type"
) -
executionExceptionMessageHeaderName
("Execution-Exception-Message"
) -
rootCauseExceptionTypeHeaderName
("Root-Cause-Exception-Type"
) -
rootCauseExceptionMessageHeaderName
("Root-Cause-Exception-Message"
)
For more information on circuit beakers and the gatewayc see the Hystrix GatewayFilter Factory section or Spring Cloud CircuitBreaker Factory section.