DIA Oracles on Aleph Zero

This repository contains the source code for DIA oracles on Aleph Zero.

Oracle Types

DIA offers two types of oracles on Aleph Zero.

Asset Price Oracle

DIA token price feeds provide smart contract real-time price information cryptocurrency assets, transparently sourced from 80+ trusted, high-volume DEXs and CEXs. The feeds facilitate the development of DeFi use cases such as money markets, lending/borrowing, synthetic asset issuance, options, derivatives and futures markets, and many more. New assets can also be supported on demand.

Supported assets

The deployed DIA oracles support the following assets

Asset	Query String	Methodology	Update Threshold
Bitcoin	BTC/USD	MAIR120	0.1%
Ether	ETH/USD	MAIR120	0.1%
USDC	USDC/USD	MAIR120	0.1%
USDT	USDT/USD	MAIR120	0.1%
DOT	DOT/USD	MAIR120	0.1%
SOL	SOL/USD	MAIR120	0.1%
AVAX	AVAX/USD	MAIR120	0.1%
EUR	EUR/USD	MAIR120	0.1%
BNB	BNB/USD	MAIR120	0.1%
DOGE	DOGE/USD	MAIR120	0.1%
MATIC	MATIC/USD	MAIR120	0.1%
DAI	DAI/USD	MAIR120	0.1%
AZERO	AZERO/USD	MAIR120	0.1%

The MAIR120 methodology is defined in detail in the DIA documentation.

Randomness Oracle

DIA xRandom provides smart contracts with unpredictable random numbers. DIA leverages drand’s distributed randomness beacon, enabling verifiable, unpredictable and unbiased random numbers. The randomness oracle enables the creation of on-chain applications including but not limited to on-chain gaming, lotteries, prediction markets, and NFT launches.

The randomness oracle is defined in detail in the DIA documentation.

Deployed Oracles

Deployed oracles can be accessed at these addresses:

Network	Oracle Name	Address	Metadata JSON
Testnet	Asset Price Oracle	5F5z8pZoLgkGapEksFWc2h7ZxH2vdh1A9agnhXvfdCeAfS9b	Price Oracle Metadata
Testnet	Randomness Oracle	5CSQdMyKCxtoeVsBC8xbufeapux3YDV74eYXcHV4UKUu1NeF	Randomness Oracle Metadata
Mainnet	Asset Price Oracle	5F7wPCMXX65RmL8oiuAFNKu2ydhvgcissDZ3NWZ5X85n2WPG	Price Oracle Metadata
Mainnet	Randomness Oracle	5HSkrQwqJtmdWL99ocRf1nMwJF9k54uHcQCU5CCctA3zf3q7	Randomness Oracle Metadata

Asset price oracle

To facilitate development, the DIA oracles are deployed on Aleph Zero mainnet and testnet. Any developer can interact with these oracles without any authentication.

Oracle contract

The smart contract is a key/value store and contains two values per asset, the timestamp of the last update and the value of the asset price. The asset price is stored with 18 decimals by default.

To interact with this contract via the aleph zero UI, you can import the metadata of the deployed contract in the Contracts UI by subscan:

• Go to https://contracts-ui.substrate.io/contract
• Choose aleph zero or aleph zero testnet on top left
• Choose Add new contract
• Choose Use Onchain Contract
• Enter the contract address
• Import the metadata json file

Compiling the smart contract

Alternatively to using the provided metadata json, you can generate it yourself. Generate the smart contract files for interacting with the contact and import the resulting file into the Aleph Zero UI.

• Install cargo and required dependencies: https://docs.alephzero.org/aleph-zero/build/aleph-zero-smart-contracts-basics/installig-required-tools
• Run cargo contract build --release
• Go to https://contracts-ui.substrate.io/contract
• Choose aleph zero testnet on top left
• Choose Add new contract
• Choose Use Onchain Contract
• Enter 5FmmcSEPiT4sZniwBMs6G89128GTTfPtaWK3jEJPJ9Z77v7U
• Import the built file ./target/ink/dia_oracle/dia_oracle.contract

Interacting with the oracle in your dApp

The example directory contains an example for how the oracle can be called by a dApp. This piece of code shows how an asset can be retrieved using the getLatestPrice() function.

        #[ink(message)]
        pub fn get(&self, key: String) -> Option<(u64, u128)> {
            self.oracle.get_latest_price(key)
        }

The key usually is the string symbol of an asset pair, for example, "BTC/USD" for the price of Bitcoin. The return value contains two values per asset, the timestamp of the last update and the value of the asset price. The asset price is stored with 18 decimals by default.

Randomness oracle

The randomness oracle is available on Aleph Zero mainnet and testnet and can be used to retrieve randomness from drand.love.

Oracle contract

Randomness is produced in numbered rounds. Each round's randomness can be retirved individually and the latest round can be queried from the contract directly. To interact with this contract via the aleph zero UI, you can import the deployed contract above.

Interacting with the oracle

The example-randomness-oracle directory contains an example for how the radnomness oracle can be called by a dApp. This piece of code shows how an asset can be retrieved using the getRandomValueForRound() function. The latest round (the required input parameter for this call) can be retrieved using the getLatestRound() function.

        #[ink(message)]
        pub fn get(&self, key: u64) -> Option<Vec<u8>> {
            self.oracle.get_random_value_for_round(key)
        }

The key is the integer round number, for example 3353171. The return value contains three values per round, the radnomness value, its signature, and the previous round's signature.

Other functions include the retrieval of the latest round ID and the historical round randomnesses.

Behind the scenes: Feeder setup

The smart contract is fed by a piece of software called the Feeder which is available as a docker image. Unless you want to re-create the entire setup and operate your own oracle, the following section is not relevant.

Environment for testing the feeder

These variables will be read from helm configs as environment variables

Name	Default Value	Description
DATABASE_URL	postgresql://user:password@host:port/dbname	Postgres database URL (optional, for recording transaction IDs)
BLOCKCHAIN_NODE	https://rpc.test.azero.dev	Blockchain RPC
PRIVATE_KEY	*insert your private updater key here*	PK of price updater
DEPLOYED_CONTRACT	5FmmcSEPiT4sZniwBMs6G89128GTTfPtaWK3jEJPJ9Z77v7U	Price anchor contract deployed
ASSETS	" Bitcoin-0x0000000000000000000000000000000000000000, Ethereum-0x0000000000000000000000000000000000000000, Ethereum-0x84cA8bc7997272c7CfB4D0Cd3D55cd942B3c9419, Ethereum-0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48, Ethereum-0xdAC17F958D2ee523a2206206994597C13D831ec7, Ethereum-0x6B175474E89094C44Da98b954EedeAC495271d0F, Ethereum-0x853d955aCEf822Db058eb8505911ED77F175b99e, BinanceSmartChain-0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56, Solana-0x0000000000000000000000000000000000000000, Polkadot-0x0000000000000000000000000000000000000000 "	Assets, whose price is to be stored in the oracle
FREQUENCY_SECONDS	86400	How often to feed price onchain
SLEEP_SECONDS	120	How often to check DEVIATION_PERMILLE, store new price if need
ORACLE_TYPE	0	Type of oracle for pricing oracle 0, and for randomness oracle 1

Note: these values are just used for testnet. Never share your production private key with anyone.

How to run to the test with your own feeder

• Fill your env vars
• Install docker
• Run:
  • docker build --tag dia-oracle:latest .
  • docker run --rm -p 3000:3000 -d dia-oracle:latest

Output

The feeder will auto feed price onchain with 18 decimals. If you want to track transaction logs, youcan access them at http://${host}/api/v1/oracle?page_size=${page_size}&page_index=${page_index}