Deployment

On BandChain, a data source can be registered into the system by anyone. This is done through the registrant sending a MsgCreateDataSource message to the chain.

A MsgCreateDataSource message contains various parameters of the data source that is to be registered. These parameters include:

• name: Name of the data source.
• description: A description of the data source .
• executable: Contents of the executable to be run by block validators upon receiving a data request for this data source.
• fee: A stipulated per-query fee that those who use this data source are required to pay.
• treasury: A treasury address of which the stipulated fee is to be paid to.
• owner: The owner address of this data source. The owner will have edit rights. If omitted, the data source parameters will no longer be able to be edited after being registered.
• sender: The message sender account.

In order to send a MsgCreateDataSource message, we can use either bandchain.js or pyband

An example on how to send a MsgCreateDataSource message via BandChain.js can be seen below.

import { band, getSigningBandClient } from '@bandprotocol/bandchain.js'
import fs from 'fs'
import path from 'path'

// Import DirectSecp256k1HdWallet from the bundled cosmjs in bandchain.js
const { DirectSecp256k1HdWallet } = await import(
  '@bandprotocol/bandchain.js/node_modules/@cosmjs/proto-signing'
)

const rpcEndpoint = 'https://rpc.band-v3-testnet.bandchain.org'
const mnemonic = process.env.MNEMONIC

async function createDataSource() {
  // Create a signer using the compatible DirectSecp256k1HdWallet
  const signer = await DirectSecp256k1HdWallet.fromMnemonic(mnemonic, {
    prefix: 'band',
  })

  const [account] = await signer.getAccounts()

  // Create a signing client
  const client = await getSigningBandClient({
    rpcEndpoint: rpcEndpoint,
    signer: signer,
  })

  // Setup the transaction's properties
  const execPath = path.resolve(__dirname, 'hello_world.py')
  const file = fs.readFileSync(execPath, 'utf8')
  const executable = Buffer.from(file).toString('base64')

  // Import the createDataSource message composer from Band's oracle module
  const { createDataSource } = band.oracle.v1.MessageComposer.withTypeUrl

  // Create a MsgCreateDataSource message
  const msgCreateDataSource = band.oracle.v1.MsgCreateDataSource.fromPartial({
    name: 'Hello World!', // Data source name
    executable: executable, // Data source executable
    treasury: account.address, // Treasury address
    owner: account.address, // Owner address
    sender: account.address, // Sender address
    fee: [{ denom: 'uband', amount: '50000' }], // Fee
    description: '' // Data source description
  })

  // Convert to properly formatted message with type URL
  const msg = createDataSource(msgCreateDataSource)

  // Set transaction fee
  const fee = {
    amount: [{ denom: 'uband', amount: '5000' }], // Transaction fee
    gas: '200000', // Gas limit
  }

  // Sign and broadcast the transaction
  const result = await client.signAndBroadcast(account.address, [msg], fee)

  return result
}

;(async () => {
  console.log(await createDataSource())
})()

An example on how to send a MsgCreateDataSource message via pyband can also be seen below.

import os

from pyband import Client, Transaction
from pyband.wallet import PrivateKey
from pyband.proto.cosmos.base.v1beta1.coin_pb2 import Coin
from pyband.proto.oracle.v1.tx_pb2 import MsgCreateDataSource
from google.protobuf.json_format import MessageToJson


def main():
    # Setup the client
    grpc_url = "laozi-testnet6.bandchain.org"
    c = Client(grpc_url)

    # Setup the wallet
    mnemonic = os.getenv("MNEMONIC")
    private_key = PrivateKey.from_mnemonic(mnemonic)
    public_key = private_key.to_public_key()
    sender_addr = public_key.to_address()
    sender = sender_addr.to_acc_bech32()

    # Prepare the transaction's properties
    deploy_msg = MsgCreateDataSource(
        name="Hello World!",
        description="",
        executable=open("hello_world.py", "rb").read(),
        fee=[Coin(amount="0", denom="uband")],
        treasury=sender,
        owner=sender,
        sender=sender,
    )

    account = c.get_account(sender)
    account_num = account.account_number
    sequence = account.sequence

    fee = [Coin(amount="50000", denom="uband")]
    chain_id = c.get_chain_id()

    # Construct the transaction
    txn = (
        Transaction()
        .with_messages(deploy_msg)
        .with_sequence(sequence)
        .with_account_num(account_num)
        .with_chain_id(chain_id)
        .with_gas(60000)
        .with_fee(fee)
    )

    # Sign the Transaction
    sign_doc = txn.get_sign_doc(public_key)
    signature = private_key.sign(sign_doc.SerializeToString())
    tx_raw_bytes = txn.get_tx_data(signature, public_key)

    # Broadcast the transaction
    tx_block = c.send_tx_block_mode(bytes(tx_raw_bytes))

    print(MessageToJson(tx_block))


if __name__ == "__main__":
    main()

After the transaction is successfully broadcasted. The newly created data source ID can be found in the response json. The registrant can also view the created data source details on CosmoScan. An example of a successful transaction will return a response similar to the one shown below.

{
  "height": "7232244",
  "txhash": "B7A039E4AE9567A7380B5241B72FF69D38DB6831BE5023F05140616AD71FFA62",
  "data": "0A200A1E2F6F7261636C652E76312E4D736743726561746544617461536F75726365",
  "rawLog": "[{\"events\":[{\"type\":\"create_data_source\",\"attributes\":[{\"key\":\"id\",\"value\":\"327\"}]},{\"type\":\"message\",\"attributes\":[{\"key\":\"action\",\"value\":\"/oracle.v1.MsgCreateDataSource\"}]}]}]",
  "logs": [
    {
      "events": [
        {
          "type": "create_data_source",
          "attributes": [
            {
              "key": "id",
              "value": "327"
            }
          ]
        },
        {
          "type": "message",
          "attributes": [
            {
              "key": "action",
              "value": "/oracle.v1.MsgCreateDataSource"
            }
          ]
        }
      ]
    }
  ],
  "gasWanted": "100000",
  "gasUsed": "55306"
}