Config: expose swap finality parameters

[h4sh3d]

This PR introduce a new section[swap...] in the config file farcasterd.toml. The swap section, for now, contains finality and safety parameters per chain per network. A chain can accept arbitrating parameters or accordant parameters, currently we only support btc and xmr:

farcaster-node/src/config.rs

Lines 239 to 246 in 981c0d1

	#[derive(Deserialize, Serialize, Debug, Clone)]
	#[serde(crate = "serde_crate")]
	pub struct SwapConfig {
	/// Swap parameters for the Bitcoin blockchain per network
	pub bitcoin: Networked<Option<ArbConfig>>,
	/// Swap parameters for the Monero blockchain per network
	pub monero: Networked<Option<AccConfig>>,
	}

The configuration can then return a parsed swap configuration for a given network, arb chain, and acc chain

farcaster-node/src/config.rs

Lines 150 to 156 in 981c0d1

	/// Returns the swap config for the specified network and arbitrating/accordant blockchains
	pub fn get_swap_config(
	&self,
	arb: ArbitratingBlockchain,
	acc: AccordantBlockchain,
	network: Network,
	) -> Result<ParsedSwapConfig, config::ConfigError> {

We have default values for mainnent and testnet for Bitcoin and Monero, if no config is found in the file we return those default value (backward compatibility), otherwise an error is returned. The configuration translate the real chain (Btc, Xmr) into its interface (Arb, Acc) as the swap is started with the offer that contains the chains used.

Launching a swap now takes the parsed swap config to

farcaster-node/src/farcasterd/runtime.rs

Lines 1244 to 1260 in 981c0d1

	let child = launch(
	"swapd",
	&[
	"--arb-finality".to_string(),
	swap_config.arbitrating.finality.to_string(),
	"--arb-safety".to_string(),
	swap_config.arbitrating.safety.to_string(),
	"--acc-finality".to_string(),
	swap_config.accordant.finality.to_string(),
	"--id".to_string(),
	swap_id.to_hex(),
	"--public-offer".to_string(),
	public_offer.to_string(),
	"--trade-role".to_string(),
	local_trade_role.to_string(),
	],
	)?;

Cli arguments of swapd have been reworked to accept the new arguments. (Breaking change with other bins that use swapd directly)

The new chains.rs file contains enums for listing support arb/acc chains in our node (e.g. btc as acc is in theory possible but probably not supported in the current architecture, but that would be a nice test to see where the current design falls apart). These structs can be reused later elsewhere (e.g. make cli args) to ensure we accept only valid params.

[h4sh3d]

@Lederstrumpf @TheCharlatan do we want to expose different finality and safety margin per network? (And are those names good?)

[TheCharlatan]

Makes sense to expose per network and names lgtm

[Lederstrumpf]

@Lederstrumpf @TheCharlatan do we want to expose different finality and safety margin per network? (And are those names good?)

agree it makes sense to have different finality thresholds per network. for safety, it would be more consistent to call this safety_threshold rather than safety_margin, but it works in the opposite direction (upper vs lower bound) to finality, so having distinct names may avoid someone misinterpreting the direction.
I'll also put suggestions of finality_min and safety_max on the table to be absolutely clear on direction since they require less thinking / a lower command of English to be understood unambiguously.

[TheCharlatan]

ACK 981c0d1

Really nice work! Would like @Lederstrumpf to ACK this as well, since it touches configuration.

[Lederstrumpf]

ACK @ bda0705
and I look forward to chains.rs spreading its claws through the node to make it chain generic 🔪 :D!

[Lederstrumpf]

👍

[Lederstrumpf]

I both hate & love this struct naming xD
I'm guessing you wanted to avoid Network because this here is limited to config? Then might go for NetworkConfig? Anyway, keen to get your rationale for this one on Monday.

[h4sh3d]

:) yes network is to generic, just wanted to express that it’s a wrapper to “network” a type. NetworkConfig would be fine (if we don’t introduce some [network..] section later) or PerNetwork maybe.

[Lederstrumpf]

(I'm holding off on merge to get #789 in first since they conflict slightly)

[Lederstrumpf]

This PR introduce a new section[swap...] in the config file farcasterd.toml. The swap section, for now, contains finality and safety parameters per chain per network. A chain can accept arbitrating parameters or accordant parameters, currently we only support btc and xmr:

...

ok - merging :). And nice new PR docs, @h4sh3d!