Console is overriding status code of HTTP requests proxied to dynamic plugin services

4.15.0-ec.2

Always

1. Create an OpenShift 4.15.0-ec.2 cluster or newer
2. Install ACM 2.9.1 from OperatorHub and create a MultiClusterHub operand
3. Expose the plugin service: oc -n multicluster-engine expose service console-mce-console
4. Set tls.termination to passthrough on route/console-mce-console
5. Compare responses from curling the proxy and the service directly.
    

$ curl -k -D - -H "Cookie: <REDACTED>" -H "If-Modified-Since: Thu, 07 Dec 2023 14:45:30 GMT" https://console-openshift-console.apps.kevin-415.dev02.red-chesterfield.com/api/plugins/mce/plugin-manifest.json
HTTP/1.1 200 OK
cache-control: no-cache
date: Wed, 10 Jan 2024 21:16:10 GMT
last-modified: Thu, 07 Dec 2023 14:45:30 GMT
referrer-policy: strict-origin-when-cross-origin
x-content-type-options: nosniff
x-dns-prefetch-control: off
x-frame-options: DENY
x-xss-protection: 1; mode=block
content-length: 0 

curl -k -D - -H "If-Modified-Since: Thu, 07 Dec 2023 14:45:30 GMT" https://console-mce-console-multicluster-engine.apps.kevin-415.dev02.red-chesterfield.com/plugin/plugin-manifest.json
HTTP/2 304 
cache-control: no-cache
last-modified: Thu, 07 Dec 2023 14:45:30 GMT
date: Wed, 10 Jan 2024 21:26:33 GMT

Response code of 304 should be returned by the proxy route, not changed to 200.

Introduced by https://github.com/openshift/console/pull/13272