Implement generic timing of blockchain rpc calls

bchain/coins/blockchain.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"reflect"
+	"time"
 
 	"github.com/juju/errors"
 )
@@ -38,5 +39,98 @@ func NewBlockChain(coin string, configfile string, pushHandler func(*bchain.MQMe
 	if err != nil {
 		return nil, errors.Annotatef(err, "Error parsing file %v", configfile)
 	}
-	return bcf(config, pushHandler, metrics)
+	bc, err := bcf(config, pushHandler, metrics)
+	if err != nil {
+		return nil, err
+	}
+	return &blockChainWithMetrics{b: bc, m: metrics}, nil
+}
+
+type blockChainWithMetrics struct {
+	b bchain.BlockChain
+	m *common.Metrics
+}
+
+func (c *blockChainWithMetrics) observeRPCLatency(method string, start time.Time, err error) {
+	c.m.RPCLatency.With(common.Labels{"method": method, "error": err.Error()}).Observe(float64(time.Since(start)) / 1e6) // in milliseconds
+}
+
+func (c *blockChainWithMetrics) Shutdown() error {
+	return c.b.Shutdown()
+}
+
+func (c *blockChainWithMetrics) IsTestnet() bool {
+	return c.b.IsTestnet()
+}
+
+func (c *blockChainWithMetrics) GetNetworkName() string {
+	return c.b.GetNetworkName()
+}
+
+func (c *blockChainWithMetrics) GetBestBlockHash() (v string, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("GetBestBlockHash", s, err) }(time.Now())
+	return c.b.GetBestBlockHash()
+}
+
+func (c *blockChainWithMetrics) GetBestBlockHeight() (v uint32, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("GetBestBlockHeight", s, err) }(time.Now())
+	return c.b.GetBestBlockHeight()
+}
+
+func (c *blockChainWithMetrics) GetBlockHash(height uint32) (v string, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("GetBlockHash", s, err) }(time.Now())
+	return c.b.GetBlockHash(height)
+}
+
+func (c *blockChainWithMetrics) GetBlockHeader(hash string) (v *bchain.BlockHeader, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("GetBlockHeader", s, err) }(time.Now())
+	return c.b.GetBlockHeader(hash)
+}
+
+func (c *blockChainWithMetrics) GetBlock(hash string, height uint32) (v *bchain.Block, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("GetBlock", s, err) }(time.Now())
+	return c.b.GetBlock(hash, height)
+}
+
+func (c *blockChainWithMetrics) GetMempool() (v []string, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("GetMempool", s, err) }(time.Now())
+	return c.b.GetMempool()
+}
+
+func (c *blockChainWithMetrics) GetTransaction(txid string) (v *bchain.Tx, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("GetTransaction", s, err) }(time.Now())
+	return c.b.GetTransaction(txid)
+}
+
+func (c *blockChainWithMetrics) EstimateSmartFee(blocks int, conservative bool) (v float64, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("EstimateSmartFee", s, err) }(time.Now())
+	return c.b.EstimateSmartFee(blocks, conservative)
+}
+
+func (c *blockChainWithMetrics) SendRawTransaction(tx string) (v string, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("SendRawTransaction", s, err) }(time.Now())
+	return c.b.SendRawTransaction(tx)
+}
+
+func (c *blockChainWithMetrics) ResyncMempool(onNewTxAddr func(txid string, addr string)) (err error) {
+	defer func(s time.Time) { c.observeRPCLatency("ResyncMempool", s, err) }(time.Now())
+	return c.b.ResyncMempool(onNewTxAddr)
+}
+
+func (c *blockChainWithMetrics) GetMempoolTransactions(address string) (v []string, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("GetMempoolTransactions", s, err) }(time.Now())
+	return c.b.GetMempoolTransactions(address)
+}
+
+func (c *blockChainWithMetrics) GetMempoolSpentOutput(outputTxid string, vout uint32) (v string) {
+	return c.b.GetMempoolSpentOutput(outputTxid, vout)
+}
+
+func (c *blockChainWithMetrics) GetMempoolEntry(txid string) (v *bchain.MempoolEntry, err error) {
+	defer func(s time.Time) { c.observeRPCLatency("GetMempoolEntry", s, err) }(time.Now())
+	return c.b.GetMempoolEntry(txid)
+}
+
+func (c *blockChainWithMetrics) GetChainParser() bchain.BlockChainParser {
+	return c.b.GetChainParser()
 }

common/metrics.go

@@ -88,7 +88,7 @@ func GetMetrics(coin string) (*Metrics, error) {
 			Buckets:     []float64{1, 5, 10, 25, 50, 75, 100, 250},
 			ConstLabels: Labels{"coin": coin},
 		},
-		[]string{"method"},
+		[]string{"method", "error"},
 	)
 	metrics.IndexResyncErrors = prometheus.NewCounterVec(
 		prometheus.CounterOpts{