evm

func EndBlocker ¶

func EndBlocker(ctx sdk.Context, bk types.BaseKeeper, n types.Nexus, m types.MultisigKeeper) ([]abci.ValidatorUpdate, error)

EndBlocker handles cross-chain message flow between EVM chains and the Axelar network. It performs two main operations each block:

1. ROUTING (EVM → Nexus): Process confirmed events from EVM chains

Events are confirmed by validators through the vote handler and queued for processing. Routing is intentionally deferred to the EndBlocker rather than being performed when the poll completes, because the last voter to complete a poll should not bear the gas cost of expensive routing operations. This ensures voting remains cheap and predictable.

Each confirmed event is routed based on its type:

• ContractCall/ContractCallWithToken → Creates a GeneralMessage in nexus and enqueues it for routing to the destination chain.

• TokenDeployed → Confirms the token deployment on the source chain, enabling cross-chain transfers for that token.

• MultisigOperatorshipTransferred → Confirms key rotation on the chain, updating the active key used for signing outbound transactions.

Unsupported event types (TokenSent, Transfer) are marked as failed.

2. DELIVERY (Nexus → EVM): Deliver pending messages to destination EVM chains

Messages routed through nexus to EVM destinations are delivered by creating gateway commands:

• GeneralMessage (no asset) → ApproveContractCall command
• GeneralMessage (with asset) → ApproveContractCallWithMint command

Commands are signed by the validator set and batched for execution on the destination chain's gateway contract.

Error Handling:

• Each event/message is processed in a cached context (RunCached). If processing fails, the cached writes are discarded but the failure is recorded.
• Failed events emit EVMEventFailed; failed messages emit ContractCallFailed.
• Failures don't block processing of subsequent events/messages.

Bounded Computation:

• Processing is limited by EndBlockerLimit per chain per block.
• Remaining events/messages are processed in subsequent blocks.

Event Emission:

• Success events (ContractCallApproved, etc.) are emitted inside RunCached, so they roll back with state if something fails.
• Failure events (EVMEventFailed, ContractCallFailed) are emitted outside RunCached, so they persist for observability even if the event/message is retried later.