cardano-oracle-publisher

Oracles on Cardano

There are two types of oracles on Cardano

• transaction metadata oracles
• oracle pools

Transaction Metadata Oracles

Those oracles are for people that will have access to full blockchain, e.g those using. https://github.com/input-output-hk/cardano-db-sync A typical use case for those oracles would be for light wallets, e.g. Yoroi, where they could simply show what was the price of ADA in USD/EUR at a given time in the past. This project addresses exactly these types of oracles.

Oracle Pools

These oracles are needed for DeFi and for smart contracts, they for cases where a smart contract (in case of Cardano UTxO based) has full access to the blockchain. This project does not cover Oracle Pools.

How to use oracle publisher?

To contribute to decentralization of the network one has to first configure metadata oracle publisher. That configuration consists of several steps:

• setup full / passive Cardano >= 1.24.1 node
• configure oracle metadata file
• get personal access keys for oracles
• generate oracle file
• register oracle via metadata key: 1967
• configure cron to keep executing post.sh script at every hour
• optionally add your own oracles

Requirements

• Full cardano passive node >= 1.24.1 synced with the main blockchain
• local generated cardano address
• linux distro of choice

Step by step guide

Firstly, we need to generate oracle metadata file, e.g.

{
  "name": "CardanoFans",
  "description": "CardanoFans - we believe in access to financial system for everybody",
  "ticker": "CRFA",
  "homepage": "https://cardano.fans",
  "address": "addr1v8yczm692pktwlvjfgwucrullt6af0lme7rh97fhfw2fgjc4chr79"
}

Please note for a functioning oracle only "address" from which transactions will be sent is necessary, the rest of fields are only used in case one has a stake pool and are optional for oracle-publisher.

Secondly, check metadata hash for this file

https://cardano.fans/mypool.metadata.json > mypool.metadata.json
cardano-cli stake-pool metadata-hash --pool-metadata-file mypool.metadata.json

5f1cbafbb46d8c8c92fae15e96170dbe6fba51cd66cda826d684bca3b0fad1bc

Thirdly, send a metadata transaction to Cardano blockchain with registration data

{
    "hash": "5f1cbafbb46d8c8c92fae15e96170dbe6fba51cd66cda826d684bca3b0fad1bc",
    "metadata": "https://cardano.fans/mypool.metadata.json"
}

Lastly,

git clone https://github.com/matiwinnetou/cardano-oracle-publisher

add to the PATH

export PATH=cardano-oracle-publisher:$PATH

and add the scripts into your crontab

crontab -e

0 * * * * cardano-oracle-publisher/post-oracle-data.sh