Awesome

Aeternity Pricefeed Oracle

The ae-oracle-pricefeed is an example service that can be hosted and allows clients to query the current price of AE.

On startup of the service following tasks are being executed:

1. The sdk-client is being initialized with the keypair provided via ./data/keypair.json (when using the command to host by hourself) or alternatively generates a new keypair if no keypair is provided
2. The service checks if the account of the provided keypair has enough funds to run the oracle
   • if NOT it prints the respective information in the console and waits for respective funding (on testnet this can easily be done using https://faucet.aepps.com/)
3. If the balance check is successful the service checks if the oracle is already registered
   • if NOT the oracle will be registered
4. The service logs the oracle id to the console
   • this will be required for other contracts or services in order to query the oracle
5. The service now periodically:
   • extends the TTL of the oracle if necessary
   • polls the node for queries that have to be answered
   • responds to queries if they exist

Host yourself

# checkout repository
git clone https://github.com/thepiwo/ae-oracle-pricefeed
cd ae-oracle-pricefeed

# build container
docker build -t ae-oracle-pricefeed .

# run, follow instructions to fund account, configure NODE_URL for other aeternity node
docker run -it --init --name pricefeed -v "$PWD/.data:/app/.data" -e NODE_URL=https://testnet.aeternity.io/ ae-oracle-pricefeed

Hosted on mainnet

There the ae-oracle-pricefeed oracle is running on mainnet:

• https://mainnet.aeternity.io/v3/oracles/ok_2NRBaMsgSDjZRFw4dU82KCqLa5W7aQdbJAzaFprTpjEGLAzroV

Sample how to query the oracle using the SDK

• implementation src/user/queryUsingSDK.js
• running NODE_URL=https://testnet.aeternity.io/ ORACLE_ID=... SECRET_KEY=... node src/user/queryUsingSDK.js will initialize the SDK, query the oracle for the AE price in EUR and wait for the response of the oracle
  • it's required to provide ORACLE_ID and SECRET_KEY
  • the ORACLE_ID should be visible in the logs of ae-oracle-pricefeed service
  • for SECRET_KEY you should - of course - use your own key and you need to make sure that the account you are using has enough funds to query the oracle (for testnet you can use https://faucet.aepps.com/)

Query the oracle in a contract

• Deploy PriceFeedQuery.aes and provide the oracle id of any compatible oracle for deployment
• Call the queryAePrice function by providing a valid coingecko currency code, e.g. eur and of course the required oracle fee for the query
  • to check the query fee call the queryFee function
  • the function will return the oracle query id
• Call the checkQueryStr function by providing the query id in order to get the response of the oracle as string, multiplied by 10^18 to provide greater int precision
• Call the checkQueryFrac function by providing the query id in order to get the response of the oracle in fractional representation