mirror of
https://gitlab.com/pulsechaincom/prysm-pulse.git
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aa1a3b3405
Former-commit-id: f8aa95e14151ae8d43d6781cdc64cced71a82e60 [formerly fbdb217576862532d2fe89f5a017d2641dfc6217] Former-commit-id: 5879301b438746facd133f21ef6b299623b346c8
111 lines
3.7 KiB
Go
111 lines
3.7 KiB
Go
package sharding
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import (
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"context"
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"fmt"
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"math/big"
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ethereum "github.com/ethereum/go-ethereum"
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"github.com/ethereum/go-ethereum/accounts"
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"github.com/ethereum/go-ethereum/accounts/abi/bind"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/log"
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"github.com/ethereum/go-ethereum/sharding/contracts"
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)
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type collatorClient interface {
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Account() (*accounts.Account, error)
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ChainReader() ethereum.ChainReader
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VMCCaller() *contracts.VMCCaller
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}
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// SubscribeBlockHeaders checks incoming block headers and determines if
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// we are an eligible proposer for collations. Then, it finds the pending tx's
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// from the running geth node and sorts them by descending order of gas price,
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// eliminates those that ask for too much gas, and routes them over
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// to the VMC to create a collation
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func subscribeBlockHeaders(c collatorClient) error {
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headerChan := make(chan *types.Header, 16)
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_, err := c.ChainReader().SubscribeNewHead(context.Background(), headerChan)
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if err != nil {
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return fmt.Errorf("unable to subscribe to incoming headers. %v", err)
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}
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log.Info("Listening for new headers...")
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for {
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// TODO: Error handling for getting disconnected from the client
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select {
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case head := <-headerChan:
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// Query the current state to see if we are an eligible proposer
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log.Info(fmt.Sprintf("Received new header: %v", head.Number.String()))
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// TODO: Only run this code on certain periods?
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if err := checkShardsForProposal(c, head); err != nil {
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return fmt.Errorf("unable to watch shards. %v", err)
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}
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}
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}
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}
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// checkShardsForProposal checks if we are an eligible proposer for
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// collation for the available shards in the VMC. The function calls
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// getEligibleProposer from the VMC and proposes a collation if
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// conditions are met
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func checkShardsForProposal(c collatorClient, head *types.Header) error {
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account, err := c.Account()
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if err != nil {
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return err
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}
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log.Info("Checking if we are an eligible collation proposer for a shard...")
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for s := int64(0); s < shardCount; s++ {
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// Checks if we are an eligible proposer according to the VMC
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period := head.Number.Div(head.Number, big.NewInt(periodLength))
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addr, err := c.VMCCaller().GetEligibleProposer(&bind.CallOpts{}, big.NewInt(s), period)
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// TODO: When we are not a proposer, we get the error of being unable to
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// unmarshal empty output. Open issue to deal with this.
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// If output is non-empty and the addr == coinbase
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if err == nil && addr == account.Address {
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log.Info(fmt.Sprintf("Selected as collator on shard: %d", s))
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err := proposeCollation(s)
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if err != nil {
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return fmt.Errorf("could not propose collation. %v", err)
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}
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}
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}
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return nil
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}
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// proposeCollation interacts with the VMC directly to add a collation header
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func proposeCollation(shardID int64) error {
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// TODO: Adds a collation header to the VMC with the following fields:
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// [
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// shard_id: uint256,
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// expected_period_number: uint256,
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// period_start_prevhash: bytes32,
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// parent_hash: bytes32,
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// transactions_root: bytes32,
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// coinbase: address,
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// state_root: bytes32,
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// receipts_root: bytes32,
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// number: uint256,
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// sig: bytes
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// ]
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//
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// Before calling this, we would need to have access to the state of
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// the period_start_prevhash. Refer to the comments in:
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// https://github.com/ethereum/py-evm/issues/258#issuecomment-359879350
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//
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// This function will call FetchCandidateHead() of the VMC to obtain
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// more necessary information.
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//
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// This functions will fetch the transactions in the txpool and and apply
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// them to finish up the collation. It will then need to broadcast the
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// collation to the main chain using JSON-RPC.
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log.Info("Propose collation function called")
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return nil
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}
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