http_proxy is ignored

[lox]

Whilst trying to solve 99designs/aws-vault#40 I noticed that aws-sdk-ruby intentionally ignores system proxies.

5af5b8d

What's the rationale? It's different behaviour from the other SDK's that I have looked at.

[trevorrowe]

To be honest, I don't recall the motivation for ignoring system proxies. Changing this at this point would possibly cause other problems, as some issue likely prompted the change.

I suspect there are valid cases for using the system proxy to contact the instance metadata service and other times where using the system proxy is undesirable or problematic. The problem here is the SDK does not give the user any control over when to use or when to ignore the system proxy.

Would it be sufficient if AWS::Core::CredentialProviders::EC2Provider#initialize accepted a :http_proxy option?

[trevorrowe]

I also did some additional digging. The Ruby SDK is not the only SDK that disables environment proxies when connecting to the instance metadata service. I spoke with one of the CLI engineers and they do the same thing.

[trevorrowe]

I'm going to move this to our feature requests. Please feel free to continue commenting on this issue.