Orchestration: use orchestrated flow as handler for monitorTransfer tap

[0xpatrickdev]

What is the Problem Being Solved?

monitorTransfers(tap) allows a developer to monitor incoming and outgoing IBC transfers for a LocalChainAccount and react to them. auto-stake-it demonstrates how to do this:

• agoric-sdk/packages/orchestration/src/examples/auto-stake-it.flows.js

  Line 78 in 67275c2

  await localAccount.monitorTransfers(tap);

However, if the receiveUpcall handler performs any multichain work, it must be written with vows:

agoric-sdk/packages/orchestration/src/examples/auto-stake-it-tap-kit.js

Lines 71 to 130 in 67275c2

	tap: {
	/**
	* Transfers from localAccount to stakingAccount, then delegates from
	* the stakingAccount to `validator` if the expected token (remoteDenom)
	* is received.
	*
	* @param {VTransferIBCEvent} event
	*/
	receiveUpcall(event) {
	trace('receiveUpcall', event);
	// ignore packets from unknown channels
	if (event.packet.source_channel !== this.state.sourceChannel) {
	return;
	}
	const tx = /** @type {FungibleTokenPacketData} */ (
	JSON.parse(atob(event.packet.data))
	);
	trace('receiveUpcall packet data', tx);
	const { remoteDenom, localChainAddress } = this.state;
	// ignore outgoing transfers
	if (tx.receiver !== localChainAddress.value) {
	return;
	}
	// only interested in transfers of `remoteDenom`
	if (tx.denom !== remoteDenom) {
	return;
	}
	const { localAccount, localDenom, remoteChainAddress } = this.state;
	return watch(
	E(localAccount).transfer(
	{
	denom: localDenom,
	value: BigInt(tx.amount),
	},
	remoteChainAddress,
	),
	this.facets.transferWatcher,
	BigInt(tx.amount),
	);
	},
	},
	transferWatcher: {
	/**
	* @param {void} _result
	* @param {bigint} value the qty of uatom to delegate
	*/
	onFulfilled(_result, value) {
	const { stakingAccount, validator, remoteDenom } = this.state;
	return watch(
	E(stakingAccount).delegate(validator, {
	denom: remoteDenom,
	value,
	}),
	);
	},
	},

Description of the Design

Demonstrate writing a tap where an orchestrated flow is the handler via auto-stake-it.

Security Considerations

Scaling Considerations

Test Plan

Upgrade Considerations

[0xpatrickdev]

Brainstorming - is there a path for adding logic to LocalOrchAccount.monitorTransfers that would allow the developer to specify a flow instead of an exo with a receiveUpcall method? If yes, is that helpful towards the goal of concision?