swarm: initial instrumentation (#15969)

* swarm: initial instrumentation with go-metrics

* swarm: initialise metrics collection and add ResettingTimer to HTTP requests

* swarm: update metrics flags names. remove redundant Timer.

* swarm: rename method for periodically updating gauges

* swarm: finalise metrics after feedback

* swarm/network: always init kad metrics containers

* swarm/network: off-by-one index in metrics containers

* swarm, metrics: resolved conflicts

1 files changed, 32 insertions, 0 deletions

diff --git a/swarm/swarm.go b/swarm/swarm.go
index 3c77d6eab..0a120db1f 100644
--- a/swarm/swarm.go
+++ b/swarm/swarm.go
@@ -34,6 +34,7 @@ import (
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/node"
 	"github.com/ethereum/go-ethereum/p2p"
 	"github.com/ethereum/go-ethereum/p2p/discover"
@@ -46,6 +47,16 @@ import (
 	"github.com/ethereum/go-ethereum/swarm/storage"
 )
 
+var (
+	startTime          time.Time
+	updateGaugesPeriod = 5 * time.Second
+	startCounter       = metrics.NewRegisteredCounter("stack,start", nil)
+	stopCounter        = metrics.NewRegisteredCounter("stack,stop", nil)
+	uptimeGauge        = metrics.NewRegisteredGauge("stack.uptime", nil)
+	dbSizeGauge        = metrics.NewRegisteredGauge("storage.db.chunks.size", nil)
+	cacheSizeGauge     = metrics.NewRegisteredGauge("storage.db.cache.size", nil)
+)
+
 // the swarm stack
 type Swarm struct {
 	config      *api.Config            // swarm configuration
@@ -262,6 +273,7 @@ Start is called when the stack is started
 */
 // implements the node.Service interface
 func (self *Swarm) Start(srv *p2p.Server) error {
+	startTime = time.Now()
 	connectPeer := func(url string) error {
 		node, err := discover.ParseNode(url)
 		if err != nil {
@@ -307,9 +319,28 @@ func (self *Swarm) Start(srv *p2p.Server) error {
 		}
 	}
 
+	self.periodicallyUpdateGauges()
+
+	startCounter.Inc(1)
 	return nil
 }
 
+func (self *Swarm) periodicallyUpdateGauges() {
+	ticker := time.NewTicker(updateGaugesPeriod)
+
+	go func() {
+		for range ticker.C {
+			self.updateGauges()
+		}
+	}()
+}
+
+func (self *Swarm) updateGauges() {
+	dbSizeGauge.Update(int64(self.lstore.DbCounter()))
+	cacheSizeGauge.Update(int64(self.lstore.CacheCounter()))
+	uptimeGauge.Update(time.Since(startTime).Nanoseconds())
+}
+
 // implements the node.Service interface
 // stops all component services.
 func (self *Swarm) Stop() error {
@@ -324,6 +355,7 @@ func (self *Swarm) Stop() error {
 		self.lstore.DbStore.Close()
 	}
 	self.sfs.Stop()
+	stopCounter.Inc(1)
 	return err
 }