api: ethrpc: implement eth_feeHistory (#9539)

Co-authored-by: Raúl Kripalani <raul@protocol.ai>

api/api_full.go

@@ -786,6 +786,7 @@ type FullNode interface {
 	NetListening(ctx context.Context) (bool, error)                                                                //perm:read
 	EthProtocolVersion(ctx context.Context) (EthUint64, error)                                                     //perm:read
 	EthGasPrice(ctx context.Context) (EthBigInt, error)                                                            //perm:read
+	EthFeeHistory(ctx context.Context, blkCount uint64, newestBlk string) (EthFeeHistory, error)                   //perm:read
 
 	EthMaxPriorityFeePerGas(ctx context.Context) (EthBigInt, error)             //perm:read
 	EthEstimateGas(ctx context.Context, tx EthCall) (EthUint64, error)          //perm:read

api/docgen/docgen.go

@@ -372,6 +372,8 @@ func init() {
 	ethhash, _ := api.EthHashFromCid(c)
 	addExample(&ethhash)
 
+	ethFeeHistoryReward := [][]api.EthBigInt{}
+	addExample(&ethFeeHistoryReward)
 }
 
 func GetAPIType(name, pkg string) (i interface{}, t reflect.Type, permStruct []reflect.Type) {

api/eth_types.go

@@ -417,3 +417,10 @@ func (h EthHash) ToCid() cid.Cid {
 
 	return cid.NewCidV1(cid.DagCBOR, mh)
 }
+
+type EthFeeHistory struct {
+	OldestBlock   uint64         `json:"oldestBlock"`
+	BaseFeePerGas []EthBigInt    `json:"baseFeePerGas"`
+	GasUsedRatio  []float64      `json:"gasUsedRatio"`
+	Reward        *[][]EthBigInt `json:"reward,omitempty"`
+}

api/mocks/mock_full.go

@@ -996,6 +996,21 @@ func (mr *MockFullNodeMockRecorder) EthEstimateGas(arg0, arg1 interface{}) *gomo
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "EthEstimateGas", reflect.TypeOf((*MockFullNode)(nil).EthEstimateGas), arg0, arg1)
 }
 
+// EthFeeHistory mocks base method.
+func (m *MockFullNode) EthFeeHistory(arg0 context.Context, arg1 uint64, arg2 string) (api.EthFeeHistory, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "EthFeeHistory", arg0, arg1, arg2)
+	ret0, _ := ret[0].(api.EthFeeHistory)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// EthFeeHistory indicates an expected call of EthFeeHistory.
+func (mr *MockFullNodeMockRecorder) EthFeeHistory(arg0, arg1, arg2 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "EthFeeHistory", reflect.TypeOf((*MockFullNode)(nil).EthFeeHistory), arg0, arg1, arg2)
+}
+
 // EthGasPrice mocks base method.
 func (m *MockFullNode) EthGasPrice(arg0 context.Context) (api.EthBigInt, error) {
 	m.ctrl.T.Helper()

api/proxy_gen.go

@@ -230,6 +230,8 @@ type FullNodeStruct struct {
 
 		EthEstimateGas func(p0 context.Context, p1 EthCall) (EthUint64, error) `perm:"read"`
 
+		EthFeeHistory func(p0 context.Context, p1 uint64, p2 string) (EthFeeHistory, error) `perm:"read"`
+
 		EthGasPrice func(p0 context.Context) (EthBigInt, error) `perm:"read"`
 
 		EthGetBalance func(p0 context.Context, p1 EthAddress, p2 string) (EthBigInt, error) `perm:"read"`
@@ -1894,6 +1896,17 @@ func (s *FullNodeStub) EthEstimateGas(p0 context.Context, p1 EthCall) (EthUint64
 	return *new(EthUint64), ErrNotSupported
 }
 
+func (s *FullNodeStruct) EthFeeHistory(p0 context.Context, p1 uint64, p2 string) (EthFeeHistory, error) {
+	if s.Internal.EthFeeHistory == nil {
+		return *new(EthFeeHistory), ErrNotSupported
+	}
+	return s.Internal.EthFeeHistory(p0, p1, p2)
+}
+
+func (s *FullNodeStub) EthFeeHistory(p0 context.Context, p1 uint64, p2 string) (EthFeeHistory, error) {
+	return *new(EthFeeHistory), ErrNotSupported
+}
+
 func (s *FullNodeStruct) EthGasPrice(p0 context.Context) (EthBigInt, error) {
 	if s.Internal.EthGasPrice == nil {
 		return *new(EthBigInt), ErrNotSupported

documentation/en/api-v1-unstable-methods.md

@@ -71,6 +71,7 @@
   * [EthCall](#EthCall)
   * [EthChainId](#EthChainId)
   * [EthEstimateGas](#EthEstimateGas)
+  * [EthFeeHistory](#EthFeeHistory)
   * [EthGasPrice](#EthGasPrice)
   * [EthGetBalance](#EthGetBalance)
   * [EthGetBlockByHash](#EthGetBlockByHash)
@@ -2228,6 +2229,33 @@ Inputs:
 
 Response: `"0x5"`
 
+### EthFeeHistory
+
+
+Perms: read
+
+Inputs:
+```json
+[
+  42,
+  "string value"
+]
+```
+
+Response:
+```json
+{
+  "oldestBlock": 42,
+  "baseFeePerGas": [
+    "0x0"
+  ],
+  "gasUsedRatio": [
+    12.3
+  ],
+  "reward": []
+}
+```
+
 ### EthGasPrice
 
 

node/impl/full/eth.go

@@ -45,6 +45,7 @@ type EthModuleAPI interface {
 	EthGetCode(ctx context.Context, address api.EthAddress, blkOpt string) (api.EthBytes, error)
 	EthGetStorageAt(ctx context.Context, address api.EthAddress, position api.EthBytes, blkParam string) (api.EthBytes, error)
 	EthGetBalance(ctx context.Context, address api.EthAddress, blkParam string) (api.EthBigInt, error)
+	EthFeeHistory(ctx context.Context, blkCount uint64, newestBlk string) (api.EthFeeHistory, error)
 	EthChainId(ctx context.Context) (api.EthUint64, error)
 	NetVersion(ctx context.Context) (string, error)
 	NetListening(ctx context.Context) (bool, error)
@@ -375,6 +376,73 @@ func (a *EthModule) EthChainId(ctx context.Context) (api.EthUint64, error) {
 	return api.EthUint64(build.Eip155ChainId), nil
 }
 
+func (a *EthModule) EthFeeHistory(ctx context.Context, blkCount uint64, newestBlkNum string) (api.EthFeeHistory, error) {
+	if blkCount > 1024 {
+		return api.EthFeeHistory{}, fmt.Errorf("block count should be smaller than 1024")
+	}
+
+	newestBlkHeight := uint64(a.Chain.GetHeaviestTipSet().Height())
+
+	// TODO https://github.com/filecoin-project/ref-fvm/issues/1016
+	var blkNum api.EthUint64
+	err := blkNum.UnmarshalJSON([]byte(`"` + newestBlkNum + `"`))
+	if err == nil && uint64(blkNum) < newestBlkHeight {
+		newestBlkHeight = uint64(blkNum)
+	}
+
+	// Deal with the case that the chain is shorter than the number of
+	// requested blocks.
+	oldestBlkHeight := uint64(1)
+	if blkCount <= newestBlkHeight {
+		oldestBlkHeight = newestBlkHeight - blkCount + 1
+	}
+
+	ts, err := a.Chain.GetTipsetByHeight(ctx, abi.ChainEpoch(newestBlkHeight), nil, false)
+	if err != nil {
+		return api.EthFeeHistory{}, fmt.Errorf("cannot load find block height: %v", newestBlkHeight)
+	}
+
+	// FIXME: baseFeePerGas should include the next block after the newest of the returned range, because this
+	// can be inferred from the newest block. we use the newest block's baseFeePerGas for now but need to fix it
+	// In other words, due to deferred execution, we might not be returning the most useful value here for the client.
+	baseFeeArray := []api.EthBigInt{api.EthBigInt(ts.Blocks()[0].ParentBaseFee)}
+	gasUsedRatioArray := []float64{}
+
+	for ts.Height() >= abi.ChainEpoch(oldestBlkHeight) {
+		// Unfortunately we need to rebuild the full message view so we can
+		// totalize gas used in the tipset.
+		block, err := a.ethBlockFromFilecoinTipSet(ctx, ts, false)
+		if err != nil {
+			return api.EthFeeHistory{}, fmt.Errorf("cannot create eth block: %v", err)
+		}
+
+		// both arrays should be reversed at the end
+		baseFeeArray = append(baseFeeArray, api.EthBigInt(ts.Blocks()[0].ParentBaseFee))
+		gasUsedRatioArray = append(gasUsedRatioArray, float64(block.GasUsed)/float64(build.BlockGasLimit))
+
+		parentTsKey := ts.Parents()
+		ts, err = a.Chain.LoadTipSet(ctx, parentTsKey)
+		if err != nil {
+			return api.EthFeeHistory{}, fmt.Errorf("cannot load tipset key: %v", parentTsKey)
+		}
+	}
+
+	// Reverse the arrays; we collected them newest to oldest; the client expects oldest to newest.
+
+	for i, j := 0, len(baseFeeArray)-1; i < j; i, j = i+1, j-1 {
+		baseFeeArray[i], baseFeeArray[j] = baseFeeArray[j], baseFeeArray[i]
+	}
+	for i, j := 0, len(gasUsedRatioArray)-1; i < j; i, j = i+1, j-1 {
+		gasUsedRatioArray[i], gasUsedRatioArray[j] = gasUsedRatioArray[j], gasUsedRatioArray[i]
+	}
+
+	return api.EthFeeHistory{
+		OldestBlock:   oldestBlkHeight,
+		BaseFeePerGas: baseFeeArray,
+		GasUsedRatio:  gasUsedRatioArray,
+	}, nil
+}
+
 func (a *EthModule) NetVersion(ctx context.Context) (string, error) {
 	// Note that networkId is not encoded in hex
 	nv, err := a.StateNetworkVersion(ctx, types.EmptyTSK)

node/rpc.go

@@ -91,6 +91,7 @@ func FullNodeHandler(a v1api.FullNode, permissioned bool, opts ...jsonrpc.Server
 		rpcServer.AliasMethod("eth_getStorageAt", "Filecoin.EthGetStorageAt")
 		rpcServer.AliasMethod("eth_getBalance", "Filecoin.EthGetBalance")
 		rpcServer.AliasMethod("eth_chainId", "Filecoin.EthChainId")
+		rpcServer.AliasMethod("eth_feeHistory", "Filecoin.EthFeeHistory")
 		rpcServer.AliasMethod("eth_protocolVersion", "Filecoin.EthProtocolVersion")
 		rpcServer.AliasMethod("eth_maxPriorityFeePerGas", "Filecoin.EthMaxPriorityFeePerGas")
 		rpcServer.AliasMethod("eth_gasPrice", "Filecoin.EthGasPrice")