Fallback provider for 5XX errors

[mrwillis]

Hi Richard,

Does fallback provider work with 5XX errors? For example, if one provider 5XX's and the other does not, does it uses the provider with the 200 response? Or does the whole thing fail?

Thanks!

[ricmoo]

A backend returning a 500 is just another failure from the FallbackProvider’s point of view, so its result is ignored. As long as there is enough correct data from the other backends for the FallbackProvider to work with, it will keep on trucking. :)

If you only have 2 backends and you have set the quorum to 2 though, they must both return the same result. You have to consider your quorum (how many must agree) with how many backends you are connecting too.

Make sense? :)

[mrwillis]

Hi @ricmoo. Does this also include 4XXs, and in general anything but 200? I.e., if a provider returns 4XX and the quorum is set to 1, will it fail totally fail or will it discard the result and use the next valid result

[ricmoo]

An error is an error, doesn’t matter if it’s 4xx or 5xx. The only exception being 429, which will cause the provider to retry. But if while retrying the stallTimeout is exceeded, the next will be kicked off. Whichever comes back with a result first wins. :)

[ricmoo]

Basically, the FallbalcProvider will do everything within its power to give you a result that matches your quorum and prioritizing your providers as you asked and weighing them accordingly. If given the responses it needs you get an answer. It only fails entirely if it could not satisfy your provider configuration constraints.