Response Compression

Response Compression allows you to compress the response from the backend before sending it to the client. This can be useful for scenarios where the backend sends large responses that can be compressed to reduce the network bandwidth. However, this comes with a trade-off of increased CPU usage on the Envoy side to compress the response.

Installation

Follow the steps from the Quickstart to install Envoy Gateway and the example manifest. Before proceeding, you should be able to query the example backend using HTTP.

Testing Response Compression

You can enable compression by specifying the compression types in the BackendTrafficPolicy resource. Multiple compression types can be defined within the resource, allowing Envoy Gateway to choose the most appropriate option based on the Accept-Encoding header provided by the client..

Envoy Gateway currently supports Brotli and Gzip compression algorithms. Additional compression algorithms may be supported in the future.

• Apply from stdin
• Apply from file

cat <<EOF | kubectl apply -f -
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: BackendTrafficPolicy
metadata:
  name: response-compression
spec:
  targetRef:
    group: gateway.networking.k8s.io
    kind: HTTPRoute
    name: backend
  compression:
    - type: Brotli
    - type: Gzip
EOF

---
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: BackendTrafficPolicy
metadata:
  name: response-compression
spec:
  targetRef:
    group: gateway.networking.k8s.io
    kind: HTTPRoute
    name: backend
  compression:
    - type: Brotli
    - type: Gzip

To specify the desired compression type, include the Accept-Encoding header in requests sent to the Envoy Gateway. The quality value (q) in the Accept-Encoding header determines the priority of each compression type. Envoy Gateway will select the compression type with the highest q value that matches a type configured in the BackendTrafficPolicy resource.

curl --verbose --header "Host: www.example.com" --header "Accept-Encoding: br;q=1.0, gzip;q=0.8" http://$GATEWAY_HOST/

*   Trying 172.18.0.200:80...
* Connected to 172.18.0.200 (172.18.0.200) port 80
> GET / HTTP/1.1
> Host: www.example.com
> User-Agent: curl/8.5.0
> Accept: */*
> Accept-Encoding: br;q=1.0, gzip;q=0.8
>
< HTTP/1.1 200 OK
< content-type: application/json
< x-content-type-options: nosniff
< date: Wed, 15 Jan 2025 08:23:42 GMT
< vary: Accept-Encoding
< content-encoding: br
< transfer-encoding: chunked

curl --verbose --header "Host: www.example.com" --header "Accept-Encoding: br;q=0.8, gzip;q=1.0" http://$GATEWAY_HOST/

*   Trying 172.18.0.200:80...
* Connected to 172.18.0.200 (172.18.0.200) port 80
> GET / HTTP/1.1
> Host: www.example.com
> User-Agent: curl/8.5.0
> Accept: */*
> Accept-Encoding: br;q=0.8, gzip;q=1.0
>
< HTTP/1.1 200 OK
< content-type: application/json
< x-content-type-options: nosniff
< date: Wed, 15 Jan 2025 08:29:22 GMT
< content-encoding: gzip
< vary: Accept-Encoding
< transfer-encoding: chunked