Interchain Query

Abstract

Stride uses interchain queries and interchain accounts to perform multichain liquid staking. The interchainquery module creates a framework that allows other modules to query other appchains using IBC. The interchainquery module is used to make bank balance ICQ queries to withdrawal account every N. The callback triggers ICA bank sends for 90% of the rewards to the delegation account and 10% to the stride hostzone revenue account. The ICA bank send logic is in x/stakeibc/keeper/callbacks.go.

Contents

1. Concepts
2. State
3. Events
4. Keeper
5. Msgs
6. Queries

State

The interchainquery module keeps Query objects and modifies the information from query to query, as defined in proto/interchainquery/v1/genesis.proto

InterchainQuery information type

Query has information types that pertain to the query itself. Query keeps the following:

1. id keeps the query identification string.
2. connection_id keeps the id of the connection between the controller and host chain.
3. chain_id keeps the id of the queried chain.
4. query_type keeps the type of interchain query (e.g. bank store query)
5. request keeps an bytecode encoded version of the interchain query
6. callback_id keeps the function that will be called by the interchain query
7. ttl time at which the query expires (in unix nano)
8. request_sent keeps a boolean indicating whether the query event has been emitted (and can be identified by a relayer)

DataPoint has information types that pertain to the data that is queried. DataPoint keeps the following:

1. id keeps the identification string of the datapoint
2. remote_height keeps the block height of the queried chain
3. local_height keeps the block height of the querying chain
4. value keeps the bytecode value of the data retrieved by the Query

Events

The interchainquery module emits an event at the end of every stride_epochs (e.g. 15 minutes on local testnet).

The purpose of this event is to send interchainqueries that query data about staking rewards, which Stride uses to reinvest (aka autocompound) staking rewards.

   event := sdk.NewEvent(
    sdk.EventTypeMessage,
    sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
    sdk.NewAttribute(sdk.AttributeKeyAction, types.AttributeValueQuery),
    sdk.NewAttribute(types.AttributeKeyQueryId, queryInfo.Id),
    sdk.NewAttribute(types.AttributeKeyChainId, queryInfo.ChainId),
    sdk.NewAttribute(types.AttributeKeyConnectionId, queryInfo.ConnectionId),
    sdk.NewAttribute(types.AttributeKeyType, queryInfo.QueryType),
    sdk.NewAttribute(types.AttributeKeyHeight, "0"),
    sdk.NewAttribute(types.AttributeKeyRequest, hex.EncodeToString(queryInfo.Request)),
   )

Keeper

Keeper Functions

interchainquery/keeper/ module provides utility functions to manage ICQs

// GetQuery returns query
GetQuery(ctx sdk.Context, id string) (types.Query, bool)
// SetQuery set query info
SetQuery(ctx sdk.Context, query types.Query)
// DeleteQuery delete query info
DeleteQuery(ctx sdk.Context, id string)
// IterateQueries iterate through queries
IterateQueries(ctx sdk.Context, fn func(index int64, queryInfo types.Query) (stop bool))
// AllQueries returns every queryInfo in the store
AllQueries(ctx sdk.Context) []types.Query

Msgs

// SubmitQueryResponse is used to return the query response back to Stride
message MsgSubmitQueryResponse {
  string chain_id = 1;
  string query_id = 2;
  bytes result = 3;
  tendermint.crypto.ProofOps proof_ops = 4;
  int64 height = 5;
  string from_address = 6;
}

Queries

// Query PendingQueries lists all queries that have been requested (i.e. emitted)
//  but have not had a response submitted yet
message QueryPendingQueriesRequest {}