Snowbridge v2 - Outbound Queue #6706

yrong · 2024-11-29T13:15:41Z

Context

This PR is for implement the design in SnowbridgeV2, essentially moving from ordered messaging system to an unordered one.

It focus more on outbound changes, inbound changes will be addressed in another PR.

The point is that we want to make V2 work side by side with V1, so add new routes/pallets specific for V2 and leave legacy codes untouched is important.

This PR is also based on XCM V5 with new instructions like AliasOrigin, InitiateTransfer in place.

Initial PR yrong#4 has been internally reviewed, companion changes required for other components of the bridge including:

Workflow

on AH we add a custom exporter returns a lower fee(without the execution cost on Ethereum including), essentially predict the route by content of XCM, more details in Predicate route table by Xcm #6074 and thanks for the review from @bkontur
On BH also add a new exporter to handle V2 specific xcm, convert the xcm to a Message structure which will be executed on Ethereum.
In OutboundQueue store the message into a Merkle tree as V1 before, and add the pending message with the fee attached into PendingOrder storage. Code here for detail. The off-chain relayer should check if relaying the message with the fee attached is profitable.
In OutboundQueue add a new extrinsic submit_delivery_proof in which to verify the Message has been delivered to Ethereum, only after that add the fee to RewardLeger which can be redeemed by the relayer later, more details in Relayer rewards paid to specified location account #6578

Review notes

Simulated test is the entry point how to build XCM for V2, also a good candidate to dig deep into the process.

cargo test -p bridge-hub-westend-integration-tests --lib tests::snowbridge_v2_outbound -- --nocapture

Co-authored-by: Vincent Geddes <[email protected]>

franciscoaguirre · 2025-01-27T18:21:52Z

bridges/snowbridge/pallets/outbound-queue-v2/src/api.rs

+		})
+		.collect();
+
+	let message = InboundMessage {


Why is this called InboundMessage? It's going from Polkadot to Ethereum, right?

Yeah, it's a bit confusing, InboundMessage here is in the context of Ethereum, the receiver end.

Maybe renaming it to OutboundMessage makes more sense here.

Obsolete, this API has been removed in #7402

bridges/snowbridge/pallets/outbound-queue-v2/src/lib.rs

bridges/snowbridge/pallets/system-frontend/src/lib.rs

bridges/snowbridge/pallets/system-v2/README.md

franciscoaguirre · 2025-01-27T20:19:58Z

bridges/snowbridge/pallets/system-v2/src/lib.rs

+
+			let command = Command::CreateAgent {};
+
+			Self::send(origin_location.clone(), command, fee)?;


Can this command fail? What happens if the storage has the agent but the actual command fails?

We just push the command to the message queue. I would assume if the send call fails, then it will also revert the agent storage change, so it might not be a problem.

bridges/snowbridge/primitives/outbound-router/src/v2/convert.rs

franciscoaguirre · 2025-01-27T20:49:28Z

bridges/snowbridge/primitives/outbound-router/src/v2/convert.rs

+			let _ = self.next();
+		}
+
+		// Try to get ENA again if it is after PNA


Why is it first ENA then PNA and then ENA again? Why can't it be PNA again afterwards?

In V2 we support to transfer ENA&PNA at the same time. To support build xcm as follows with PNA&ENA in whatever order.
https://github.com/yrong/polkadot-sdk/blob/82ab0eee2b3c8331d75be8403e59d6f978b4d223/cumulus/parachains/integration-tests/emulated/tests/bridges/bridge-hub-westend/src/tests/snowbridge_v2_outbound.rs#L212-L215

Co-authored-by: Francisco Aguirre <[email protected]>

…-sdk into outbound-queue-v2

acatangiu · 2025-01-31T15:12:14Z

bridges/snowbridge/pallets/outbound-queue-v2/README.md

@@ -0,0 +1,3 @@
+# Ethereum Outbound Queue
+
+Sends messages from an origin in the Polkadot ecosystem to Ethereum.


please more detailed docs: design, APIs, usage, etc

could also be done as code docs (example) instead of README

acatangiu · 2025-01-31T15:14:32Z

bridges/snowbridge/pallets/outbound-queue-v2/runtime-api/README.md

I would move the contents of this to bridges/snowbridge/pallets/outbound-queue-v2/runtime-api/src/lib.rs as high-level code docs: example

bridges/snowbridge/pallets/outbound-queue-v2/runtime-api/src/lib.rs

acatangiu · 2025-01-31T15:22:30Z

bridges/snowbridge/pallets/outbound-queue-v2/runtime-api/src/lib.rs

+		/// `sp_runtime::generic::DigestItem::Other`
+		fn prove_message(leaf_index: u64) -> Option<MerkleProof>;
+
+		fn dry_run(xcm: Xcm<()>) -> Result<(OutboundMessage,Balance),DryRunError>;


this needs an origin too to work properly, no? or does the impl always assume origin is AH?

The origin is derived from AliasOrigin here

Btw, the dry_run here is used only to convert the xcm to an abi-encoded message in order to estimate the cost on Ethereum later.

acatangiu · 2025-01-31T15:34:24Z

bridges/snowbridge/pallets/outbound-queue-v2/src/envelope.rs

+/// An inbound message that has had its outer envelope decoded.
+#[derive(Clone, RuntimeDebug)]
+pub struct Envelope<T: Config> {
+	/// The address of the outbound queue on Ethereum that emitted this message as an event log
+	pub gateway: H160,
+	/// A nonce for enforcing replay protection and ordering.
+	pub nonce: u64,
+	/// Delivery status
+	pub success: bool,
+	/// The reward address
+	pub reward_address: T::AccountId,
+}


Without having read all the code and figuring this out, just by looking at these types and their documentation I am utterly confused.

Is this "inbound" in what context? inbound for BH or inbound for Ethereum? it's on the BH outbound queue crate so I am guessing it's envelope for BH->Ethereum message, but then the outer comment just says "inbound" instead of "outbound", and the inner gateway says outbound q on Ethereum that emitted this message, meaning it IS in fact inbound to BH (Ethereum->BH). But then I'm confused why there are different envelopes (one in inbound-q-v2 and one here) for Ethereum->BH messages?

all in all, needs much more detailed/clearer docs

meaning it IS in fact inbound to BH (Ethereum->BH). why there are different envelopes (one in inbound-q-v2 and one here) for Ethereum->BH messages?

Exactly. The inbound message here is actually the delivery proof sent from Ethereum to BH. Workflow and some details I added in #6706 (comment).

Sorry, it's a bit confusion here. We'll try to improve the docs/address the comments in #7402 Vincent added recently, we think it may be better to review the V2 changes in a single PR at this moment.

I suggest also explicit naming like MessageEnvelope and DeliveryProofEnvelope

We've renamed Envelope to DeliveryReceipt in https://github.com/vgeddes/polkadot-sdk/pull/6/files#diff-7952d3d8e20c7cdc1126ab6f7ef3965b1867f0dbc36fcee70eb0317a7691186dR16

acatangiu · 2025-01-31T15:38:36Z

bridges/snowbridge/pallets/outbound-queue-v2/src/lib.rs

+//! 2. The message is then enqueued for later processing via the implementation for
+//!    [`snowbridge_outbound_primitives::v2::SendMessage::deliver`]
+//! 3. The underlying message queue is implemented by [`Config::MessageQueue`]
+//! 4. The message queue delivers messages back to this pallet via the implementation for


they are not really coming "back", no?

Suggested change

//! 4. The message queue delivers messages back to this pallet via the implementation for

//! 4. The message queue delivers messages to this pallet via the implementation for

acatangiu · 2025-01-31T15:40:31Z

bridges/snowbridge/pallets/outbound-queue-v2/src/lib.rs

+//!    [`frame_support::traits::ProcessMessage::process_message`]
+//! 5. The message is processed in `Pallet::do_process_message`: a. Assigned a nonce b. ABI-encoded,
+//!    hashed, and stored in the `MessageLeaves` vector
+//! 6. At the end of the block, a merkle root is constructed from all the leaves in `MessageLeaves`.


Suggested change

//! 6. At the end of the block, a merkle root is constructed from all the leaves in `MessageLeaves`.

//! 6. At the end of the block, a merkle root is constructed from all the leaves in `MessageLeaves`,

//! then `MessageLeaves` is dropped so that it is never committed to storage or included in PoV.

yrong · 2025-02-14T11:03:42Z

Closed in favor of #7402

We'll address all left comments there.

yrong and others added 30 commits November 11, 2024 10:34

Merge from master

d359108

Fix v2 tests

4d6c678

Fix compile

a72aa5a

Merge branch 'master' into outbound-queue-v2

cf8a9c3

Rename to OutboundQueueV2Api

056fd7f

Return raw balance for dry run

49837cf

Decode account asap

030d95c

Revamp comments for V2

206b300

Custom digest for V2

8b3e178

Cleanup imports

a22f0ac

Update bridges/snowbridge/pallets/outbound-queue-v2/src/types.rs

e346bf6

Co-authored-by: Vincent Geddes <[email protected]>

Clean up with the insert

9847bc9

Remove Fee for V2

fb3b30c

Reorgnize InboundMessage to abi module

83b6ff8

Seperate XcmConverter

f08e36e

Merge branch 'master' into outbound-queue-v2

cff1cba

Merge branch 'snowbridge-v2' into outbound-queue-v2

faf25e9

Support multiple commands in one message

af928ba

Rename to InvalidPendingNonce & Cleanup

d5ab77b

Improve comment

f96a6fc

Fix breaking tests

d4910ea

Merge branch 'snowbridge-v2' into outbound-queue-v2

7586a28

Remove Inbound-queue V2 completely

8e80315

Reorgnize code layout

e8951e4

For Transact

2a41399

Transact support

66afb07

Remove irrelevant changes

78da35b

Validate fee asset is always in WETH

4808c36

Check ether value is sufficient

84cbb93

Merge branch 'master' into outbound-queue-v2

ec6ceb8

yrong added 5 commits January 14, 2025 16:54

Update WETH address

bc7599c

Update import

6a333b7

Cleanup

553ea2c

Create agent with V2 system api

f2f805c

Merge branch 'master' into outbound-queue-v2

1e9e6bc

franciscoaguirre added the T15-bridges This PR/Issue is related to bridges. label Jan 27, 2025

franciscoaguirre reviewed Jan 27, 2025

View reviewed changes

Update bridges/snowbridge/pallets/outbound-queue-v2/src/lib.rs

3f3253f

Co-authored-by: Francisco Aguirre <[email protected]>

paritytech-review-bot bot requested a review from a team January 30, 2025 01:16

yrong and others added 15 commits January 30, 2025 09:31

Update bridges/snowbridge/pallets/outbound-queue-v2/src/lib.rs

ac6fd91

Co-authored-by: Francisco Aguirre <[email protected]>

Update bridges/snowbridge/pallets/outbound-queue-v2/src/lib.rs

80fcee6

Co-authored-by: Francisco Aguirre <[email protected]>

Update bridges/snowbridge/pallets/outbound-queue-v2/src/lib.rs

2f5a8b2

Co-authored-by: Francisco Aguirre <[email protected]>

Update bridges/snowbridge/pallets/system-frontend/README.md

9f171ab

Co-authored-by: Francisco Aguirre <[email protected]>

Update bridges/snowbridge/pallets/system-frontend/src/lib.rs

6f1f5e6

Co-authored-by: Francisco Aguirre <[email protected]>

Update bridges/snowbridge/pallets/system-frontend/src/lib.rs

222c282

Co-authored-by: Francisco Aguirre <[email protected]>

Comments

22e1288

Update bridges/snowbridge/pallets/system-frontend/src/lib.rs

7925528

Co-authored-by: Francisco Aguirre <[email protected]>

Update bridges/snowbridge/primitives/outbound-router/src/v2/convert.rs

7d263d2

Co-authored-by: Francisco Aguirre <[email protected]>

Rename to OutboundMessage

30d1c36

Merge branch 'master' into outbound-queue-v2

1d70de7

Fix tests

82ab0ee

Update bridges/snowbridge/pallets/system-v2/README.md

ce6ce35

Co-authored-by: Francisco Aguirre <[email protected]>

Fix clippy

c96a1b2

Merge branch 'outbound-queue-v2' of https://github.com/yrong/polkadot…

15aceae

…-sdk into outbound-queue-v2

vgeddes mentioned this pull request Jan 30, 2025

Snowbridge V2 #7402

Draft

acatangiu reviewed Jan 31, 2025

View reviewed changes

bkontur added a commit that referenced this pull request Feb 6, 2025

Add @ claravanstaden's RewardLedger trait support from #6706

98ebe39

yrong mentioned this pull request Feb 13, 2025

Address comments in PR Snowbridge-v2 vgeddes/polkadot-sdk#6

Merged

yrong closed this Feb 14, 2025

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Snowbridge v2 - Outbound Queue #6706

Snowbridge v2 - Outbound Queue #6706

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yrong commented Feb 14, 2025


		let command = Command::CreateAgent {};

		Self::send(origin_location.clone(), command, fee)?;

		@@ -0,0 +1,3 @@
		# Ethereum Outbound Queue

		Sends messages from an origin in the Polkadot ecosystem to Ethereum.

	//! 4. The message queue delivers messages back to this pallet via the implementation for
	//! 4. The message queue delivers messages to this pallet via the implementation for

	//! 6. At the end of the block, a merkle root is constructed from all the leaves in `MessageLeaves`.
	//! 6. At the end of the block, a merkle root is constructed from all the leaves in `MessageLeaves`,
	//! then `MessageLeaves` is dropped so that it is never committed to storage or included in PoV.

Snowbridge v2 - Outbound Queue #6706

Snowbridge v2 - Outbound Queue #6706

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yrong commented Nov 29, 2024 • edited Loading

Context

Workflow

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yrong commented Feb 14, 2025

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