Concepts
The oracle module is very minimal, but users should understand what the Oracle is and how it interacts with ICQ.
Oracle
The Oracle is a custom built CosmWasm smart contract that the chain queries for data. Chain users can update the address with a proposal.
Interchain Queries (ICQ)
ICQ is heavily leveraged in order to allow one Provenance Blockcahin to query another Provenance Blockchain's Oracle. This module acts as both the Controller and receiver of the Host in the ICQ realm.
When a user intends to query another chain, they initiate the process by submitting a query through a transaction on the ICQ Controller. This Controller delivers the query from the transaction to the ICQ Host module of the destination chain via IBC. Subsequently, the received query is routed by the ICQ Host to this module. Upon receipt, the module queries the Oracle using the provided input, and the resulting information is then transmitted back to the ICQ Controller in the form of an ACK message.
It should be noted that responses, which arrive in the form of the ACK, indicate that queries operate asynchronously. Consequently, these results will not be immediately accessible, requiring the user to wait for an emitted event on the response. For additional details, you can refer to the Async ICQ Module developed by strangelove-ventures.
Note
For ICQ to function correctly, it is essential to establish an unordered channel connecting the two chains. This channel should be configured utilizing the oracle and icqhost ports on the ICQ Controller and ICQ Host correspondingly. The version should be designated as icq-1. Moreover, it is crucial to ensure that the HostEnabled parameter is enabled with a value of true, while the AllowQueries parameter should encompass the path "/provenance.oracle.v1.Query/Oracle".