Oracle Consumer Chain

The oracle-consumer is an application of the Cosmos SDK that demonstrates the use of the pricefeed-module implemented by BandProtocol. This module allows other Cosmos SDK applications to easily obtain data from BandChain through IBC.

• oracle-consumerd: The Oracle Consumer Daemon and command-line interface (CLI). Runs a full node of the consumer application.

oracle-consumer is built on the Cosmos SDK using the following modules:

• x/consumer: Consume data from pricefeed module.
• x/pricefeed: Logic of requesting data from BandChain.

Prerequisites

Be sure you have met the prerequisites before you install and use Consumer Chain

Operating systems

• Ubuntu 22.04

Go (for ignite and consumer chain)

• 1.19.5 or higher

Rust (for Hermes Relayer)

• 1.65.0 or higher

Running Consumer Chain

This guide will provide instructions on how to install the oracle-consumerd binary and run the CLI on a server. By following these steps, you will have the binary properly set up and ready to use.

Install ignite CLI

Ignite CLI is an easy-to-use CLI tool for creating and maintaining sovereign application-specific blockchains. Blockchains created with Ignite CLI use Cosmos SDK and Tendermint.

To install the ignite binary in /usr/local/bin run the following command:

curl https://get.ignite.com/cli! | bash

Installing build-essential package in Ubuntu

sudo apt update && sudo apt install build-essential

Install the binaries and run consumer chain

git clone -b <latest-release-tag> https://github.com/bandprotocol/oracle-consumer.git
cd oracle-consumer & ignite chain serve -v

You can locate the <latest-release-tag> here.

When you initiate the chain, the Alice and Bob mnemonic will be displayed in your logging. Kindly preserve this mnemonic for use in the section below.

[IGNITE] ✔ Added account alice with address cosmos1d2dymcelkm6qgfaje3t4xt8vlpqfn227nvu9ja and mnemonic:
[IGNITE]   [your alice mnemonic]
[IGNITE] ✔ Added account bob with address cosmos1cn9yzz5p7scdc7s0he7vujyfcvtldlnv86tnys and mnemonic:
[IGNITE]   [your bob mnemonic]

By executing the command ignite chain serve -v, the oracle-consumerd binary will be installed and your consumer chain will start running.

Verify that everything is installed successfully by running:

oracle-consumerd version --long

You should see something similar to the following:

...
build_tags: ""
commit: ...
cosmos_sdk_version: v0.46.12
go: go version go1.19.5 darwin/amd64
name: Oracle-Consumer
server_name: oracle-consumerd
version: ""

Connecting Hermes Relayer to BandChain

The last step is to set up a relayer to listen and relay IBC packets between an oracle-consumer chain and BandChain.

Here are the simple guides for setting up a relayer.

• Setup Hermes Relayer

Open and Vote the source channel param change proposal

The current default value for the source channel is [not_set]. If you wish to obtain BandChain data through IBC, you will need to open the proposal to change the source channel param to your own source channel. An example of how to open parameter change proposal is provided below.

Create proposal.json

Note: this example has been provided in example/proposals/source-channel-params-change.json

{
  "title": "Param change for SourceChannel",
  "description": "Proposal for change SourceChannel param in pricefeed module",
  "changes": [
    {
      "subspace": "pricefeed",
      "key": "SourceChannel",
      "value": "channel-0"
    }
  ],
  "deposit": "10000000stake"
}

Submit proposal

oracle-consumerd tx gov submit-legacy-proposal param-change example/proposals/source-channel-params-change.json --from alice

Vote the proposal

oracle-consumerd tx gov vote 1 yes --from alice

oracle-consumerd tx gov vote 1 yes --from bob

Open and Vote the update symbol requests proposal

The purpose of this proposal is to request price data from BandChain at block_interval specified in the proposal. If the proposal is approved, the pricefeed module will retrieve the data and store the response on the consumer chain.

Create proposal.json

Note: this example has been provided in example/proposals/update-symbol-requests.json

{
    "title": "Update Symbol requests",
    "description": "Update symbol that request price from BandChain",
    "symbol_requests": [
        {
            "symbol": "BTC",
            "oracle_script_id": "396",
            "block_interval": "40"
        },
        {
            "symbol": "ETH",
            "oracle_script_id": "396",
            "block_interval": "40"
        }
    ],
    "deposit": "10000000stake"
}

You can also delete symbol request by set "block_interval": "0" on this proposal.

Submit proposal

oracle-consumerd tx gov submit-legacy-proposal update-symbol-request example/proposals/update-symbol-requests.json --from alice

Vote the proposal

oracle-consumerd tx gov vote 2 yes --from alice

oracle-consumerd tx gov vote 2 yes --from bob

Check proposal status

oracle-consumerd query gov proposals

Another way to initiate source channel and symbol requests

To utilize the Ignite feature to replace the genesis state, insert the code shown below into the config.yml file. and restat the chin by using ignite chain serve -r -v command.

genesis:
  app_state:
    pricefeed:
      params:
        source_channel: "channel-0"
      symbol_requests: [{"symbol": "BAND", "oracle_script_id": 396, "block_interval":  40}]

Query latest price that got from BandChain

Query latest price that got from BandChin via pricefeed module

oracle-consumerd query pricefeed price BAND

Query latest price that got from BandChin via consumer module

oracle-consumerd query consumer price BAND