HTTP connection settings

Configure and manage HTTP connections to an upstream service.

Supported HTTP connection settings

You can use a BackendConfigPolicy to apply HTTP connection settings to a service in your cluster. These settings include general settings, such as connection timeouts or the maximum number of connections that an upstream service can receive. You can also configure settings for HTTP/2 and HTTP/1 requests.

• General connection settings
• HTTP protocol options
• Additional HTTP 1.0 protocol options

General connection settings

Configure the timeout and read/write buffer limits for a connection.

kind: BackendConfigPolicy
apiVersion: gateway.kgateway.dev/v1alpha1
metadata:
  name: httpbin-policy
  namespace: gwtest
spec:
  targetRefs:
    - name: httpbin
      group: ""
      kind: Service
  connectTimeout: 5s
  perConnectionBufferLimitBytes: 1024

HTTP protocol options

You can use a BackendConfigPolicy to configure additional connection options when handling upstream HTTP requests. Note that these options are applied to HTTP/1 and HTTP/2 requests.

kind: BackendConfigPolicy
apiVersion: gateway.kgateway.dev/v1alpha1
metadata:
  name: httpbin-policy
  namespace: gwtest
spec:
  targetRefs:
    - name: httpbin
      group: ""
      kind: Service
  commonHttpProtocolOptions:
    idleTimeout: 10s  
    maxHeadersCount: 15
    maxStreamDuration: 30s
    maxRequestsPerConnection: 100 
    headersWithUnderscoresAction: RejectRequest

Additional HTTP 1.0 protocol options

The BackendConfigPolicy allows you to apply additional configuration to HTTP/1 connections.

kind: BackendConfigPolicy
apiVersion: gateway.kgateway.dev/v1alpha1
metadata:
  name: httpbin-policy
  namespace: gwtest
spec:
  targetRefs:
    - name: httpbin
      group: ""
      kind: Service
  http1ProtocolOptions:
    enableTrailers: true
    overrideStreamErrorOnInvalidHttpMessage: true
    headerFormat: PreserveCaseHeaderKeyFormat

Before you begin

1. Follow the Get started guide to install kgateway.

2. Follow the Sample app guide to create a gateway proxy with an HTTP listener and deploy the httpbin sample app.

3. Get the external address of the gateway and save it in an environment variable.

   Cloud Provider LoadBalancerPort-forward for local testing

   export INGRESS_GW_ADDRESS=$(kubectl get svc -n kgateway-system http -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
   echo $INGRESS_GW_ADDRESS  

   kubectl port-forward deployment/http -n kgateway-system 8080:8080

Configure backend connections

1. Create a BackendConfigPolicy that applies connection configuration to the httpbin app.

   kubectl apply -f- <<EOF
   kind: BackendConfigPolicy
   apiVersion: gateway.kgateway.dev/v1alpha1
   metadata:
     name: httpbin-connection
     namespace: httpbin   
   spec:
     targetRefs:
       - name: httpbin
         group: ""
         kind: Service
     connectTimeout: 5s
     perConnectionBufferLimitBytes: 1024
     commonHttpProtocolOptions:
       idleTimeout: 10s  
       maxHeadersCount: 15
       maxStreamDuration: 30s
       maxRequestsPerConnection: 100 
       headersWithUnderscoresAction: RejectRequest
     http1ProtocolOptions:
       enableTrailers: true
       overrideStreamErrorOnInvalidHttpMessage: true
       headerFormat: PreserveCaseHeaderKeyFormat
   EOF

2. Port-forward the gateway proxy on port 19000.

   kubectl port-forward deployment/http -n kgateway-system 19000

3. Get the configuration of your gateway proxy as a config dump.

   curl -X POST 127.0.0.1:19000/config_dump\?include_eds > gateway-config.json

4. Open the config dump and find the kube_httpbin_httpbin_8000 cluster. Verify that you see all the connection settings that you enabled in your BackendConfigPolicy.

   Example output

   ...
   "connect_timeout": "5s",
      "per_connection_buffer_limit_bytes": 1024,
      "metadata": {},
      "upstream_connection_options": {
      },
      "typed_extension_protocol_options": {
       "envoy.extensions.upstreams.http.v3.HttpProtocolOptions": {
        "@type": "type.googleapis.com/envoy.extensions.upstreams.http.v3.HttpProtocolOptions",
        "common_http_protocol_options": {
         "idle_timeout": "10s",
         "max_headers_count": 15,
         "max_stream_duration": "30s",
         "headers_with_underscores_action": "REJECT_REQUEST",
         "max_requests_per_connection": 100
        },
        "explicit_http_config": {
         "http_protocol_options": {
          "header_key_format": {
           "stateful_formatter": {
            "name": "envoy.http.stateful_header_formatters.preserve_case",
            "typed_config": {
             "@type": "type.googleapis.com/envoy.extensions.http.header_formatters.preserve_case.v3.PreserveCaseFormatterConfig"
            }
           }
          },
          "enable_trailers": true,
          "override_stream_error_on_invalid_http_message": true
         }
        }
       }
      }
   ...
   

Cleanup

kubectl delete backendconfigpolicy httpbin-connection -n httpbin