Allow overwriting exit code

[danielpacak]

Dear Maintainers,

I'm running Conftest as a Kubernetes Job. In case of any failure Conftest returns non zero exit code, hence the Job is failing.
A quick and dirty solution that I came up with is to use the following command:

sh -c "conftest test --output json --all-namespaces --policy /project/policy /project/workload.yaml || true"

However, I'd love to overwrite exit code with a flag:

conftest test --exit-code 0 --output json --all-namespaces --policy /project/policy /project/workload.yaml 

Do you think it makes sense to allow overwriting exit code? If yes would you be interested in reviewing a PR that adds the exit-code flag? Or please advice otherwise.

[jpreese]

Can you think of any scenarios where you'd want to set the exit code to a non-zero number?

I could see adding a flag such as --no-fail which would make it such that conftest would always return zero. Would this work for your use case?

[danielpacak]

In my case I want to set exit code to 0 when policies are evaluated with no errors so the --no-fail flag would be enough.

[jpreese]

The OPA binary uses --fail and --fail-defined for its eval command so --no-fail feels appropriate. PR added here: #547