make /api/ h2c compatible

[therealak12]

This pull request tries to solve issue#452.

Based on envoy docs the gprc-web filter just translates grpc-web sent over HTTP/1.1 to the same format over HTTP/2.

As grpc-web uses GRPC format (not for example JSON format used by grpc-gateway), making the API compatible with HTTP/2 should be enough to solve the issue.

The h2c.NewHandler would handle h2c requests and simply forward HTTP/1.1 requests to the wrapped http.Handler.

The code should work with an HTTPProxy object of Contour with the following spec:

apiVersion: projectcontour.io/v1
kind: HTTPProxy
metadata:
  name: hubble-ui
  namespace: cilium-system
spec:
  routes:
  - conditions:
    - prefix: /api/
    enableWebsockets: true
    services:
    - name: hubble-ui-grpc
      port: 80
      protocol: h2c
  - enableWebsockets: true
    services:
    - name: hubble-ui
      port: 80
  virtualhost:
    fqdn: sample.example.com

The hubble-ui-grpc service referenced above is a service that targets the backend ports of hubble-ui pods. It may look like this:

apiVersion: v1
kind: Service
metadata:
  name: hubble-ui-grpc
  namespace: cilium-system
spec:
  ports:
  - name: grpc
    port: 80
    protocol: TCP
    targetPort: 8090
  selector:
    k8s-app: hubble-ui
  type: ClusterIP

[geakstr]

Thanks!

[vflaux]

Hi,

I can confirm that it fixes the issue #452, so thank you!

I also had to increase the default timeout of envoy which is 15s as it causes frequent disconnection/reconnection error messages :

spec:
  routes:
  - timeoutPolicy:
      response: 1h

So with your example:

apiVersion: projectcontour.io/v1
kind: HTTPProxy
metadata:
  name: hubble-ui
  namespace: cilium-system
spec:
  routes:
  - conditions:
    - prefix: /api/
    enableWebsockets: true
    services:
    - name: hubble-ui-grpc
      port: 80
      protocol: h2c
    timeoutPolicy:
      response: 1h
  - enableWebsockets: true
    services:
    - name: hubble-ui
      port: 80
  virtualhost:
    fqdn: sample.example.com