Add response headers

Emissary can add a dictionary of HTTP headers that can be added to each response that is returned to the client.

The add_response_headers attribute

The add_response_headers attribute is a dictionary of header: value pairs. The value can be a string, bool or object. When it is an object, the object should have a value property, which is the actual header value, and the remaining attributes are additional envoy properties.

Envoy dynamic values %DOWNSTREAM_REMOTE_ADDRESS_WITHOUT_PORT% and %PROTOCOL% are supported, in addition to static values.

add_response_headers can be set either in a Mapping or using ambassador Module defaults.

Mapping example

---
apiVersion: getambassador.io/v2
kind:  Mapping
metadata:
  name:  quote-backend
spec:
  prefix: /backend/
  add_response_headers:
    x-test-proto: "%PROTOCOL%"
    x-test-ip: "%DOWNSTREAM_REMOTE_ADDRESS_WITHOUT_PORT%"
    x-test-static: This is a test header
    x-test-object:
      append: False
      value: this is from object header config
  service: quote

will add the protocol, client IP, and a static header to the response returned to the client.

Defaults example

apiVersion: getambassador.io/v2
kind: Module
metadata:
  name: ambassador
spec:
  config:
    defaults:
      httpmapping:
        add_response_headers:
          x-test-proto: "%PROTOCOL%"
          x-test-ip: "%DOWNSTREAM_REMOTE_ADDRESS_WITHOUT_PORT%"
          x-test-static: This is a test header
          x-test-object:
            append: False
            value: this is from object header config
---
apiVersion: getambassador.io/v2
kind: Mapping
metadata:
  name: quote-backend1
spec:
  prefix: /backend1/
  service: quote
---
apiVersion: getambassador.io/v2
kind: Mapping
metadata:
  name: quote-backend2
spec:
  prefix: /backend2/
  service: quote

This example will add the same headers for both mappings.

Last modified September 9, 2024: Update all 1.14 metadata to fix navigation (c0afada)