Feature Request: allow configuration of http/api path

[karl-tpio]

I am sorry i can't just open a PR... i am not a very seasoned goLang dev.

I did look through the .go files that appear to handle the /api/* requests, and the change did look pretty reasonable. But then i did a search for /containers and found that the path appears to be hard-coded in multiple places... which might make this a bit harder to implement. If that's the case, i completely get it.

In any event, I am requesting a --http_base_path=/containers or similar command line option which will change the base path that all web resources are loaded from.

The Reason for the ask: I use cadvisor and some other monitoring software - call it netmon for the purposes of this post - on each of my individual hosts. Both cadvisor and netmon sit behind a reverse proxy that performs authentication and enforces some TLS/Cipher requirements.

unfortunately both cadvisor and netmon both use a hard-coded /api path. Neither supports changing this, and this makes it impossible to tell the reverse proxy to route (authenticated) requests to /api/* to the correct host/port.

Thanks for your time. Happy to provide more detail if needed and or work on documentation.

[dashpole]

Can does url_base_prefix meet your needs? See #2117

[karl-tpio]

@dashpole Yes it does!

I'm ashamed to admit that i didn't fully go through the --help text, only consulted the doc here:
https://github.com/google/cadvisor/blob/master/docs/runtime_options.md

Shall i close this issue and open a PR against that document to include the url_base_prefix option?

[dashpole]

Please do, thanks.

[karl-tpio]

Done!

#2379