Crate pallet_oracle

Oracle

A pallet that provides a decentralized and trustworthy way to bring external, off-chain data onto the blockchain.

Pallet API

See the pallet module for more information about the interfaces this pallet exposes, including its configuration trait, dispatchables, storage items, events and errors.

Overview

The Oracle pallet enables blockchain applications to access real-world data through a decentralized network of trusted data providers. It’s designed to be flexible and can handle various types of external data such as cryptocurrency prices, weather data, sports scores, or any other off-chain information that needs to be brought on-chain.

The pallet operates on a permissioned model where only authorized oracle operators can submit data. This ensures data quality and prevents spam while maintaining decentralization through multiple independent operators. The system aggregates data from multiple sources using configurable algorithms, typically taking the median to resist outliers and manipulation attempts.

Key Concepts

• Oracle Operators: A set of trusted accounts authorized to submit data. Managed through the [SortedMembers] trait, allowing integration with membership pallets.
• Data Feeds: Key-value pairs where keys identify the data type (e.g., currency pair) and values contain the actual data (e.g., price).
• Data Aggregation: Configurable algorithms to combine multiple operator inputs into a single trusted value, with median aggregation provided by default.
• Timestamped Data: All submitted data includes timestamps for freshness tracking.

Low Level / Implementation Details

Design Goals

The oracle system aims to provide:

• Decentralization: Multiple independent data providers prevent single points of failure
• Data Quality: Aggregation mechanisms filter out outliers and malicious data
• Flexibility: Configurable data types and aggregation strategies
• Performance: Efficient storage and retrieval of timestamped data
• Security: Permissioned access with cryptographic verification of data integrity

Design

The pallet uses a dual-storage approach:

• RawValues: Stores individual operator submissions with timestamps
• Values: Stores the final aggregated values after processing

This design allows for:

• Historical tracking of individual operator submissions
• Efficient access to final aggregated values
• Clean separation between raw data and processed results
• Easy integration with data aggregation algorithms

Re-exports

pub use traits::CombineData;

pub use traits::DataFeeder;

pub use traits::DataProvider;

pub use traits::DataProviderExtended;

pub use traits::OnNewData;

pub use weights::WeightInfo;

pub use pallet::*;

Modules

pallet

The pallet module in each FRAME pallet hosts the most important items needed to construct this pallet.

traits

This module provides traits for data feeding and provisioning.

weights

Autogenerated weights for pallet_oracle

Macros

create_median_value_data_provider

Creates a median data provider from a list of other data providers.

Structs

DefaultCombineData

Sort by value and returns median timestamped value. Returns prev_value if not enough valid values.

Traits

BenchmarkHelper

Helper trait for benchmarking oracle operations.