created_at2024-02-02 14:02:55.138529
updated_at2024-02-15 08:10:30.775125
descriptionDharitri Price aggregator Smart Contract




Price aggregator


The price-aggregator smart contract keeps track of the price between multiple pairs of tokens. Compared to the other chainlink contracts, it is a simplified and easier to use version.



  • staking_token - the token used for staking and slashing
  • staking_amount - the minimum staked amount required for a used to be considered a board member
  • slash_amount - the amount to be slashed from a board member on a successful slash vote
  • slash_quorum - the minimum number of board members required for a vote to be considered successful
  • oracles - the list of addresses which are allowed to submit price feed updates
  • submission_count - the minimum number of submissions from different oracles which trigger an update of the price feed

Configuring the number of decimals

The number of decimals for a given token pair can be set by calling setPairDecimals(from, to, decimals). Notes:

  • only the owner can configure the number of decimals
  • the contract must be paused first
  • this method also clears the submissions accumulated so far
  • no submissions will be accepted for any given pair unless the number of decimals is configured first
  • every oracle must change its configuration to provide submissions with the new number of decimals, as any mismatch will be considered a configuration error and the submission will be rejected

Submitting price feed updates

An oracle can submit a price feed update using one of the endpoints:

  • submit - submit a single price feed as 5 arguments (from, to, submission_timestamp, price and decimals).
  • submitBatch - submit multiple price feeds simultaneously. The number of arguments must be a multiple of 5.

Note: the decimals argument must match the value returned by getPairDecimals for that specific pair, otherwise the submission will be rejected.


Price feeds from multiple oracles are collected. When a certain threshold number of submissions has been reached (given by submission_count), a new round is created. The price feed recorded in the round is the median value out of all submissions made.

Querying the price feeds


  • latestRoundData takes no arguments and returns all the latest price feeds.
  • latestPriceFeed takes a filter (as the from and to token identifiers) and returns a single price feed. The transaction fails if there is no price feed for the given filter.
  • latestPriceFeedOptional behaves like latestPriceFeed but it returns an option so that the caller can handle the lack of a price feed.

A price feed contains:

  • round_id - the ID of the current round (not related to the blockchain round ID)
  • from - the first token
  • to - the second token
  • price - the price between the two tokens
  • decimals - the number of decimals for the price
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cargo fmt