Blockstack Oracle

Blockstack Oracle is a sample clarity smart contract for the Stacks Blockchain. The repo includes an oracle script which updates the bitcoin price using a public smart contract function based on the API results. This script can be run periodically using a cron script.

Key considerations

• Only the contract owner can update the oracle address using update-oracle-address public function.

• Only the oracle address can update the bitcoin price using update-bitcoin-price public function.

Getting Started

1. Install npm and nodejs

2. Install cli-blockstack

   git clone https://github.com/blockstack/cli-blockstack.git
   cd cli-blockstack
   git checkout feature/stacks-2.0-tx
   npm install
   npm run build
   npm link blockstack
   sudo npm link
   cd ..
   

3. Clone blockstack_oracle Repo

   git clone https://github.com/viraja1/blockstack_oracle.git
   

4. Change directory

   cd blockstack_oracle
   

5. Install Packages

   npm install
   

6. Run tests

   npm test 
   

7. Create STX addresses and save keychain details for testnet

   Address to deploy contract

   blockstack make_keychain -t > owner_keychain.txt
   

   Address for oracle

   blockstack make_keychain -t > oracle_keychain.txt
   

   You will need privateKey and address from both the keychain files for the further steps

8. Fund both the addresses using testnet faucet

   https://testnet-explorer.blockstack.org/sandbox?tab=faucet

9. Update addresses in contracts/oracle.clar and test/oracle.ts

   Update oracle-address and contract-owner with the value of address from owner_keychain.txt

10. Deploy the contract using the credentials from owner_keychain.txt

    cd contracts
    blockstack deploy_contract ./oracle.clar oracle 2000 {nonce} {privateKey} -t
    

    In the above command replace {privateKey} with the value from owner_keychain.txt

    Nonce value can be fetched from the following command

    blockstack balance {address} -t
    

    In the above command replace {address} with the value from owner_keychain.txt

11. Update oracle address

    blockstack call_contract_func {address} oracle update-oracle-address 2000 {nonce} {privateKey} -t
    

    In the above command replace {privateKey} and {address} with the value from owner_keychain.txt

    Nonce value can be fetched from the following command

    blockstack balance {address} -t
    

    The prompt will then ask for oracle address. Fill it with the value of address from oracle_keychain.txt

12. Update the env variables for oracle script based on owner_keychain.txt and oracle_keychain.txt

    export CONTRACT_ADDRESS={ownerAddress}
    export CONTRACT_NAME=oracle
    export STACKS_ADDRESS={oracleAddress}
    export STACKS_PRIVATE_KEY={oraclePrivateKey}
    

    In the above commands, replace {ownerAddress} with the address value from owner_keychain.txt and replace {oraclePrivateKey} and {oracleAddress} with the privateKey and address value from oracle_keychain.txt

13. Run the oracle script

    cd ..
    ./oracle_update_price.sh