Make response-ratelimiting plugin and rate-limiting plugin return the same response when limited (or at least be more consistent).

[nricklin]

When rate limited, the rate-limiting plugin returns a 429 with the following response body:

{"message":"API rate limit exceeded"}

However the response-ratelimiting plugin returns a 429 but with a blank response body.

I propose to make response-ratelimiting return the same message, I assume simply by tweaking this line to include a message:
https://github.com/Mashape/kong/blob/923639ba45253108a0a1940cd359bbb93f58128b/kong/plugins/response-ratelimiting/header_filter.lua#L54

I think it offers a more consistent experience for API users to see the same error message when rate limited.

I'll do a pull request if it makes sense to others.

[sonicaghi]

@thefosk ^

[thibaultcha]

Sounds good to me, the only exception being that the response-ratelimiting plugin is supposed to be renamed "quotas" as per #579, so the response should probably be:

{"message":"API quota exceeded"}

PRs welcome, indeed

[nricklin]

Alright, it's in there in pull request #733 with a response of:

{"message":"API quota exceeded"}

It was a bit more than that one-liner. I had to move the blocking response from the header_filter to the action part of the plugin.

[nricklin]

I just verified in kong 0.5.2 (using the AWS AMI) that if you set a response-ratelimiting limit to N, then this will happen:

• The first N requests make it through correctly
• Request N+1 does in fact hit the upstream server, but the response from kong is 429.

This pull request #733 should fix this issue as well.