Is it possible to return a string (stdout) from dagger but still exit with a non-zero status code?

[tropic wigeon]

I am trying to run ruff check --output-format github and ruff formata --check inside Dagger.

This is supposed to fail on linting rules violation, but still output valuable data (to be picked up as GitHub PR annotations).

As far as I can tell, Dagger can either return stdout and exit with 0 or just fail without any stdout.

I found the expect option, but that's still not exactly what I need

container.with_exec(
    args,
    expect=ReturnType.ANY
)

[tropic wigeon]

Is it possible to return a string (stdout) from dagger but still exit with a non-zero status code?

[modest temple]

Hmm IIRC you should be able to get the stdout of the command even if it fails

Do you have a dagger cloud trace?

[violet elk]

I think you're on the right path with expect. You can still check the exit code and get stdout/stderr

[modest temple]

my understanding was that expect shouldn't be necessary in this case, unless you specifically want/need the command not to fail

if the command fails, you can still capture the error and the stdout/err even if it fails

[violet elk]

How?

[modest temple]

i.e:

func (m *Fofo) Test(ctx context.Context) (string, error) {
    return dag.Container().From("alpine:latest").
        WithExec([]string{"sh", "-c", "echo hello && exit 1"}).Stdout(ctx)
}

^ that will return both the error and the output

[violet elk]

But can you get that stdout to another function in code? If it exits like that the pipeline will bail out

[modest temple]

it really depends on what you do with the code

you can get the error, assert the status code and decide what to do

my point is that you don't need to do anything for that. The stdout function will give you both the error and the output

and then you decide what you want to do

[violet elk]

But in python it will raise an exception

[modest temple]

my undersanding from the op's request is that you couldn't get the stdout when the command fails which you actually can

[modest temple]

yes, you can still get it from the ExecException ExceError I think

there's a typed exception which gives you both stdout and stderr

here: https://github.com/dagger/dagger/blob/7aabd50f2d466968961c2a48ee55eaee4572e6c3/sdk/python/src/dagger/_exceptions.py#L144

[tropic wigeon]

Thanks @modest temple, I’ll look into it. My main problem was returning exactly the stdout from ruff (without raising any errors) but also setting a non-zero status code.

[modest temple]

If you don't want to raise any errors, then using expect would be the way to go.

You mentioned that expect doesn't seem to be what you need. Could you expand on that a bit?