Using Accept header for `aop-prometheus` endpoint causes error response

[osoriano]

Without any Accept header, the aop-prometheus endpoint returns a successful response

orca> wget -S http://localhost:8083/aop-prometheus
Connecting to localhost:8083 ([::1]:8083)
  HTTP/1.1 200
  Content-Type: text/plain; version=0.0.4;charset=utf-8
  Content-Length: 31287
  ...

When using the Accept a 406 error response is returned

orca> wget -S --header 'Accept: text/plain; version=0.0.4' http://localhost:8083/aop-prometheus
Connecting to localhost:8083 ([::1]:8083)
  HTTP/1.1 406
wget: server returned error: HTTP/1.1 406

The prometheus spring-boot WebEndpoint doesn't have this issue. Looking at the code for the aop endpoint, the Accept header may not have been implemented due to issues with plugins/WebEndpoint

[osoriano]

The Prometheus scraper I'm using sends the Accept header, so I'll have to make some changes

[osoriano]

Switching to the WebEndpoint got past the issue osoriano@cb15f3b

[osoriano]

Still seeing 406 on clouddriver though. I wonder if this is related spinnaker/clouddriver#3846