When I make a call setting up the automation API like:

await stack.setAllConfig({
  'aws:region': { value: 'eu-west-1' },
});

I see that a

Pulumi.<stack-id>.yaml

file is created. Is there a way to supply config where no file gets created?

Looking at the docs, the automation API seems to assume writing/reading to the

Pulumi..yaml

. You can try passing an explicit

workDir

in the options, e.g.

/tmp

https://www.pulumi.com/docs/reference/pkg/nodejs/pulumi/pulumi/automation/#LocalWorkspaceOptions-workDir Which, tracing through the code from

setAllConfig

the answer seems to be because the automation api is simply wrapping the pulumi cli https://github.com/pulumi/pulumi/blob/72d48f162e7d6f288a5c5e5944ec90ce483824a5/sdk/nodejs/automation/cmd.ts#L55 https://github.com/pulumi/pulumi/blob/72d48f162e7d6f288a5c5e5944ec90ce483824a5/sdk/nodejs/automation/localWorkspace.ts#L416-L424

Thanks!