malus: add finality_delay cli flag

[ordian]

This allows to pass a --finality-delay X cli param to malus to configure the finality delay.

The ugly part is that it's feature gated with #[cfg(feature = "malus")] in new_full function. However, due to how cargo resolves features, in some packages, malus is enabled when launching from workspace root, but not if individually (e.g. running only adder-collator tests). I'm open to ideas to how avoid that w/o exposing this flag to validators. This param propagates to cumulus unfortunately, not sure if there's a sane way to hide it.

cumulus companion: paritytech/cumulus#1442

[sandreim]

I don't think it is a good idea to add any malus stuff in the real node. We should add a mechanism that allows us to feed any override into the node from the malus crate.

There is another CLI flag that might help with your testing -

polkadot/cli/src/cli.rs

Line 112 in decdbed

pub grandpa_pause: Vec<u32>,

Does this work ?

[ordian]

I don't think it is a good idea to add any malus stuff in the real node.

The cli flag is now only available for malus binaries. As an extra protection, it's only activated if malus feature is enabled.

We should add a mechanism that allows us to feed any override into the node from the malus crate.

new_full is already a way to pass this override. Whether we pass a bunch of params or a closure that will take another bunch or params, it doesn't change that. We could create a wrapper for build_full for cumulus and non-malus node that doesn't expose malus-specific flags if that's helpful.

There is another CLI flag that might help with your testing

I'm not sure yet if grandpa_pause will be enough for my use case, but it's less flexible in that only delay finality once (which might make some of the tests more flaky).

[ordian]

bot merge