Enable estimatefee rpc command.

mempool/estimatefee.go

@@ -12,9 +12,9 @@ import (
 	"sort"
 	"sync"
 
-	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/roasbeef/btcd/chaincfg/chainhash"
-	"github.com/btcsuite/btcd/mining"
+	"github.com/roasbeef/btcd/mining"
-	"github.com/btcsuite/btcutil"
+	"github.com/roasbeef/btcutil"
 )
 
 // TODO incorporate Alex Morcos' modifications to Gavin's initial model

mempool/estimatefee_test.go

@@ -8,10 +8,10 @@ import (
 	"math/rand"
 	"testing"
 
-	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/roasbeef/btcd/chaincfg/chainhash"
-	"github.com/btcsuite/btcd/mining"
+	"github.com/roasbeef/btcd/mining"
-	"github.com/btcsuite/btcd/wire"
+	"github.com/roasbeef/btcd/wire"
-	"github.com/btcsuite/btcutil"
+	"github.com/roasbeef/btcutil"
 )
 
 // newTestFeeEstimator creates a feeEstimator with some different parameters

rpcclient/chain.go

@@ -557,6 +557,43 @@ func (c *Client) GetRawMempoolVerbose() (map[string]btcjson.GetRawMempoolVerbose
 	return c.GetRawMempoolVerboseAsync().Receive()
 }
 
+// FutureEstimateFeeResult is a future promise to deliver the result of a
+// EstimateFeeAsync RPC invocation (or an applicable error).
+type FutureEstimateFeeResult chan *response
+
+// Receive waits for the response promised by the future and returns the info
+// provided by the server.
+func (r FutureEstimateFeeResult) Receive() (float64, error) {
+	res, err := receiveFuture(r)
+	if err != nil {
+		return -1, err
+	}
+
+	// Unmarshal result as a getinfo result object.
+	var fee float64
+	err = json.Unmarshal(res, &fee)
+	if err != nil {
+		return -1, err
+	}
+
+	return fee, nil
+}
+
+// EstimateFeeAsync returns an instance of a type that can be used to get the result
+// of the RPC at some future time by invoking the Receive function on the
+// returned instance.
+//
+// See EstimateFee for the blocking version and more details.
+func (c *Client) EstimateFeeAsync(numBlocks int64) FutureEstimateFeeResult {
+	cmd := btcjson.NewEstimateFeeCmd(numBlocks)
+	return c.sendCmd(cmd)
+}
+
+// EstimateFee provides an estimated fee  in bitcoins per kilobyte.
+func (c *Client) EstimateFee(numBlocks int64) (float64, error) {
+	return c.EstimateFeeAsync(numBlocks).Receive()
+}
+
 // FutureVerifyChainResult is a future promise to deliver the result of a
 // VerifyChainAsync, VerifyChainLevelAsyncRPC, or VerifyChainBlocksAsync
 // invocation (or an applicable error).

rpcserver.go

@@ -132,6 +132,7 @@ var rpcHandlersBeforeInit = map[string]commandHandler{
 	"debuglevel":            handleDebugLevel,
 	"decoderawtransaction":  handleDecodeRawTransaction,
 	"decodescript":          handleDecodeScript,
+	"estimatefee":           handleEstimateFee,
 	"generate":              handleGenerate,
 	"getaddednodeinfo":      handleGetAddedNodeInfo,
 	"getbestblock":          handleGetBestBlock,
@@ -224,7 +225,6 @@ var rpcAskWallet = map[string]struct{}{
 
 // Commands that are currently unimplemented, but should ultimately be.
 var rpcUnimplemented = map[string]struct{}{
-	"estimatefee":      {},
 	"estimatepriority": {},
 	"getchaintips":     {},
 	"getmempoolentry":  {},
@@ -254,6 +254,7 @@ var rpcLimited = map[string]struct{}{
 	"createrawtransaction":  {},
 	"decoderawtransaction":  {},
 	"decodescript":          {},
+	"estimatefee":           {},
 	"getbestblock":          {},
 	"getbestblockhash":      {},
 	"getblock":              {},
@@ -853,6 +854,28 @@ func handleDecodeScript(s *rpcServer, cmd interface{}, closeChan <-chan struct{}
 	return reply, nil
 }
 
+// handleEstimateFee handles estimatefee commands.
+func handleEstimateFee(s *rpcServer, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
+	c := cmd.(*btcjson.EstimateFeeCmd)
+
+	if s.cfg.FeeEstimator == nil {
+		return nil, errors.New("Fee estimation disabled")
+	}
+
+	if c.NumBlocks <= 0 {
+		return -1.0, errors.New("Parameter NumBlocks must be positive")
+	}
+
+	feeRate, err := s.cfg.FeeEstimator.EstimateFee(uint32(c.NumBlocks))
+
+	if err != nil {
+		return -1.0, err
+	}
+
+	// Convert to satoshis per kb.
+	return float64(feeRate.ToSatoshiPerKb()), nil
+}
+
 // handleGenerate handles generate commands.
 func handleGenerate(s *rpcServer, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
 	// Respond with an error if there are no addresses to pay the
@@ -4247,6 +4270,10 @@ type rpcserverConfig struct {
 	TxIndex   *indexers.TxIndex
 	AddrIndex *indexers.AddrIndex
 	CfIndex   *indexers.CfIndex
+
+	// The fee estimator keeps track of how long transactions are left in
+	// the mempool before they are mined into blocks.
+	FeeEstimator *mempool.FeeEstimator
 }
 
 // newRPCServer returns a new instance of the rpcServer struct.

rpcserverhelp.go

@@ -115,6 +115,15 @@ var helpDescsEnUS = map[string]string{
 	"decodescript--synopsis": "Returns a JSON object with information about the provided hex-encoded script.",
 	"decodescript-hexscript": "Hex-encoded script",
 
+	// EstimateFeeCmd help.
+	"estimatefee--synopsis": "Estimate the fee per kilobyte in satoshis " +
+		"required for a transaction to be mined before a certain number of " +
+		"blocks have been generated.",
+	"estimatefee-numblocks": "The maximum number of blocks which can be " +
+		"generated before the transaction is mined.",
+	"estimatefee--result0": "Estimated fee per kilobyte in satoshis for a block to " +
+		"be mined in the next NumBlocks blocks.",
+
 	// GenerateCmd help
 	"generate--synopsis": "Generates a set number of blocks (simnet or regtest only) and returns a JSON\n" +
 		" array of their hashes.",
@@ -663,6 +672,7 @@ var rpcResultTypes = map[string][]interface{}{
 	"debuglevel":            {(*string)(nil), (*string)(nil)},
 	"decoderawtransaction":  {(*btcjson.TxRawDecodeResult)(nil)},
 	"decodescript":          {(*btcjson.DecodeScriptResult)(nil)},
+	"estimatefee":           {(*float64)(nil)},
 	"generate":              {(*[]string)(nil)},
 	"getaddednodeinfo":      {(*[]string)(nil), (*[]btcjson.GetAddedNodeInfoResult)(nil)},
 	"getbestblock":          {(*btcjson.GetBestBlockResult)(nil)},

server.go

@@ -2586,6 +2586,7 @@ func newServer(listenAddrs []string, db database.DB, chainParams *chaincfg.Param
 			TxIndex:      s.txIndex,
 			AddrIndex:    s.addrIndex,
 			CfIndex:      s.cfIndex,
+			FeeEstimator: feeEstimator,
 		})
 		if err != nil {
 			return nil, err