OpenFaas outputs and logging

[onlyjsmith]

@onlyjsmith commented on Tue Dec 11 2018

Anything that an OpenFaas function writes to STDOUT will be sent back to the user. For R, this is like the result of print("all fine") or anything that writes/prints back to the console.

R also has a function message("some text") which writes to STDERR. We're still exploring exactly how OpenFaas works, but this STDERR is a separate stream to STDOUT and is often used in R for arbitrary logging. I've added a use of message in the OpenFaas version of this (https://github.com/disarm-platform/fn-covariate-extractor).

I think it's useful to think about logging while we're compiling these early functions.

[alexellis]

Hi @onlyjsmith please don't struggle, just head over to OpenFaaS and raise an issue or join Slack.

For your use-case you can just set combine_output to false to prevent stderr being returned to the user. This is documented in the workshop https://github.com/openfaas/workshop/

Alex