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Protocol State

State Overview​

Every data market has a final state that includes, but is not limited to the following:

  • Epoch size
  • Epochs released in the past
  • Present epoch
  • Allowed snapshotter identities
  • To be implemented:
    • Allowed validator identities
  • Snapshot submission window
  • Snapshot submissions from allowed snapshotters
  • Project IDs on which submissions are accepted
  • Snapshot submissions as content identifiers(CIDs) per epoch
    • Occurrence count of their submissions
    • Mapping between allowed snapshotter identities and the CIDs they submitted

Implementation of the Protocol State​

Presently, the protocol state is implemented as a smart contract on an EVM-compatible chain that is affectionately referred to internally as the Prost Chain.

Chain and Contract Address​

Depending on the node type, the network RPC and the deployed contract address can be found in the env.example file in either the deploy (for Full Nodes) and snapshotter repositories (for Lite Nodes).

ABI​

The Application Binary Interface (ABI) to interact with the smart contract can be found within the snapshotter repository.

State Modification Functions​

function updateProjects(string[] calldata _projects, bool[] calldata _status) external onlyOwnerOrValidator​

Used by signalers and other actors in the dynamic data market ecosystem.

function updateSnapshotters(address[] calldata _snapshotters, bool[] calldata _status) external onlyOwner​

Presently used to allow authorized snapshotters on our experimental testnets. To be deprecated soon with decentralized data markets.

function updateValidators(address[] calldata _validators, bool[] calldata _status) external onlyOwner​

Self-explanatory.

function forceSkipEpoch(uint256 begin, uint256 end) public onlyOwner​

Optional usage for an additional trusted service to ensure consensus is reached in case of unstable peers or actors in a data market.

function releaseEpoch(uint256 begin, uint256 end) public onlyOwnerOrValidator​

Used by the epoch generator service.

function submitSnapshot(string memory snapshotCid, uint256 epochId, string memory projectId, Request calldata request, bytes calldata signature) public​

Used to submit snapshots by the allowed snapshotter identities.

State View Functions​

Self-explanatory​

uint8 public EPOCH_SIZE; // Number of Blocks in each Epoch
uint256 public SOURCE_CHAIN_ID;
uint256 public SOURCE_CHAIN_BLOCK_TIME; // Block time in seconds * 1e4 (to allow decimals)
uint256 public DeploymentBlockNumber;
bool public USE_BLOCK_NUMBER_AS_EPOCH_ID;
uint256 public snapshotSubmissionWindow = 1; // Number of blocks to wait before finalizing epoch

uint256 public minSubmissionsForConsensus = 2; // Minimium number of snapshots for consensus

Epoch Information​

mapping(uint256 => EpochInfo) public epochInfo;

struct EpochInfo {
    uint256 timestamp;
    uint256 blocknumber;
    uint256 epochEnd;
}

Snapshot submission information​

mapping(string => mapping(uint256 => uint256)) public maxSnapshotsCount;
mapping(string => mapping(uint256 => string)) public maxSnapshotsCid;
mapping(string => mapping(uint256 => ConsensusStatus)) public snapshotStatus;

Allowed projects and snapshotters​

mapping(string => bool) public projects;
mapping(address => bool) public snapshotters;

Events​

event SnapshottersUpdated(address snapshotterAddress, bool allowed);
event ProjectsUpdated(string projectId, bool allowed, uint256 enableEpochId);
event ValidatorsUpdated(address validatorAddress, bool allowed);

// snapshotters listen to this event, generate snapshots and submit to contract
event EpochReleased(uint256 indexed epochId, uint256 begin, uint256 end, uint256 timestamp);

event SnapshotSubmitted(address indexed snapshotterAddr, string snapshotCid, uint256 indexed epochId, string projectId, uint256 timestamp);

event DelayedSnapshotSubmitted(address indexed snapshotterAddr, string snapshotCid, uint256 indexed epochId, string projectId, uint256 timestamp);

event SnapshotFinalized(uint256 indexed epochId, uint256 epochEnd, string projectId, string snapshotCid, uint256 timestamp);

See Also​