ethclient: add FeeHistory support (ethereum#25403)

ethclient/ethclient.go

@@ -473,6 +473,38 @@ func (ec *Client) SuggestGasTipCap(ctx context.Context) (*big.Int, error) {
 	return (*big.Int)(&hex), nil
 }
 
+type feeHistoryResultMarshaling struct {
+	OldestBlock  *hexutil.Big     `json:"oldestBlock"`
+	Reward       [][]*hexutil.Big `json:"reward,omitempty"`
+	BaseFee      []*hexutil.Big   `json:"baseFeePerGas,omitempty"`
+	GasUsedRatio []float64        `json:"gasUsedRatio"`
+}
+
+// FeeHistory retrieves the fee market history.
+func (ec *Client) FeeHistory(ctx context.Context, blockCount uint64, lastBlock *big.Int, rewardPercentiles []float64) (*ethereum.FeeHistory, error) {
+	var res feeHistoryResultMarshaling
+	if err := ec.c.CallContext(ctx, &res, "eth_feeHistory", hexutil.Uint(blockCount), toBlockNumArg(lastBlock), rewardPercentiles); err != nil {
+		return nil, err
+	}
+	reward := make([][]*big.Int, len(res.Reward))
+	for i, r := range res.Reward {
+		reward[i] = make([]*big.Int, len(r))
+		for j, r := range r {
+			reward[i][j] = (*big.Int)(r)
+		}
+	}
+	baseFee := make([]*big.Int, len(res.BaseFee))
+	for i, b := range res.BaseFee {
+		baseFee[i] = (*big.Int)(b)
+	}
+	return &ethereum.FeeHistory{
+		OldestBlock:  (*big.Int)(res.OldestBlock),
+		Reward:       reward,
+		BaseFee:      baseFee,
+		GasUsedRatio: res.GasUsedRatio,
+	}, nil
+}
+
 // EstimateGas tries to estimate the gas needed to execute a specific transaction based on
 // the current pending state of the backend blockchain. There is no guarantee that this is
 // the true gas limit requirement as other transactions may be added or removed by miners,

interfaces.go

@@ -183,6 +183,15 @@ type GasPricer interface {
 	SuggestGasPrice(ctx context.Context) (*big.Int, error)
 }
 
+// FeeHistory provides recent fee market data that consumers can use to determine
+// a reasonable maxPriorityFeePerGas value.
+type FeeHistory struct {
+	OldestBlock  *big.Int     // block coresponding to first response value
+	Reward       [][]*big.Int // list every txs priority fee per block
+	BaseFee      []*big.Int   // list of each block's base fee
+	GasUsedRatio []float64    // ratio of gas used out of the total available limit
+}
+
 // A PendingStateReader provides access to the pending state, which is the result of all
 // known executable transactions which have not yet been included in the blockchain. It is
 // commonly used to display the result of ’unconfirmed’ actions (e.g. wallet value

internal/ethapi/api.go

@@ -109,6 +109,7 @@ type feeHistoryResult struct {
 	GasUsedRatio []float64        `json:"gasUsedRatio"`
 }
 
+// FeeHistory returns the fee market history.
 func (s *PublicEthereumAPI) FeeHistory(ctx context.Context, blockCount hexutil.Uint, lastBlock rpc.BlockNumber, rewardPercentiles []float64) (*feeHistoryResult, error) {
 	oldest, reward, baseFee, gasUsed, err := s.b.FeeHistory(ctx, int(blockCount), lastBlock, rewardPercentiles)
 	if err != nil {