Move metrics ticker to log pkg for #67

log/metrics.go

@@ -0,0 +1,62 @@
+package log
+
+import (
+	"container/list"
+	"expvar"
+	"strings"
+	"time"
+)
+
+// TickerFunc is the type of metrics function accepted by AddTickerFunc
+type TickerFunc func()
+
+var tickerFuncChan = make(chan TickerFunc)
+
+func init() {
+	go metricsTicker()
+}
+
+// AddTickerFunc adds a new function callback to the list of metrics TickerFuncs that get
+// called each minute.
+func AddTickerFunc(f TickerFunc) {
+	tickerFuncChan <- f
+}
+
+// PushMetric adds the metric to the end of the list and returns a comma separated string of the
+// previous 61 entries.  We return 61 instead of 60 (an hour) because the chart on the client
+// tracks deltas between these values - there is nothing to compare the first value against.
+func PushMetric(history *list.List, ev expvar.Var) string {
+	history.PushBack(ev.String())
+	if history.Len() > 61 {
+		history.Remove(history.Front())
+	}
+	return joinStringList(history)
+}
+
+// joinStringList joins a List containing strings by commas
+func joinStringList(listOfStrings *list.List) string {
+	if listOfStrings.Len() == 0 {
+		return ""
+	}
+	s := make([]string, 0, listOfStrings.Len())
+	for e := listOfStrings.Front(); e != nil; e = e.Next() {
+		s = append(s, e.Value.(string))
+	}
+	return strings.Join(s, ",")
+}
+
+func metricsTicker() {
+	funcs := make([]TickerFunc, 0)
+	ticker := time.NewTicker(time.Minute)
+
+	for {
+		select {
+		case <-ticker.C:
+			for _, f := range funcs {
+				f()
+			}
+		case f := <-tickerFuncChan:
+			funcs = append(funcs, f)
+		}
+	}
+}

smtpd/listener.go

@@ -16,6 +16,28 @@ import (
 	"github.com/jhillyerd/inbucket/msghub"
 )
 
+func init() {
+	m := expvar.NewMap("smtp")
+	m.Set("ConnectsTotal", expConnectsTotal)
+	m.Set("ConnectsHist", expConnectsHist)
+	m.Set("ConnectsCurrent", expConnectsCurrent)
+	m.Set("ReceivedTotal", expReceivedTotal)
+	m.Set("ReceivedHist", expReceivedHist)
+	m.Set("ErrorsTotal", expErrorsTotal)
+	m.Set("ErrorsHist", expErrorsHist)
+	m.Set("WarnsTotal", expWarnsTotal)
+	m.Set("WarnsHist", expWarnsHist)
+
+	log.AddTickerFunc(func() {
+		expReceivedHist.Set(log.PushMetric(deliveredHist, expReceivedTotal))
+		expConnectsHist.Set(log.PushMetric(connectsHist, expConnectsTotal))
+		expErrorsHist.Set(log.PushMetric(errorsHist, expErrorsTotal))
+		expWarnsHist.Set(log.PushMetric(warnsHist, expWarnsTotal))
+		expRetentionDeletesHist.Set(log.PushMetric(retentionDeletesHist, expRetentionDeletesTotal))
+		expRetainedHist.Set(log.PushMetric(retainedHist, expRetainedCurrent))
+	})
+}
+
 // Server holds the configuration and state of our SMTP server
 type Server struct {
 	// Configuration
@@ -179,44 +201,3 @@ func (s *Server) Drain() {
 	log.Tracef("SMTP connections have drained")
 	s.retentionScanner.Join()
 }
-
-// When the provided Ticker ticks, we update our metrics history
-func metricsTicker(t *time.Ticker) {
-	ok := true
-	for ok {
-		_, ok = <-t.C
-		expReceivedHist.Set(pushMetric(deliveredHist, expReceivedTotal))
-		expConnectsHist.Set(pushMetric(connectsHist, expConnectsTotal))
-		expErrorsHist.Set(pushMetric(errorsHist, expErrorsTotal))
-		expWarnsHist.Set(pushMetric(warnsHist, expWarnsTotal))
-		expRetentionDeletesHist.Set(pushMetric(retentionDeletesHist, expRetentionDeletesTotal))
-		expRetainedHist.Set(pushMetric(retainedHist, expRetainedCurrent))
-	}
-}
-
-// pushMetric adds the metric to the end of the list and returns a comma separated string of the
-// previous 61 entries.  We return 61 instead of 60 (an hour) because the chart on the client
-// tracks deltas between these values - there is nothing to compare the first value against.
-func pushMetric(history *list.List, ev expvar.Var) string {
-	history.PushBack(ev.String())
-	if history.Len() > 61 {
-		history.Remove(history.Front())
-	}
-	return JoinStringList(history)
-}
-
-func init() {
-	m := expvar.NewMap("smtp")
-	m.Set("ConnectsTotal", expConnectsTotal)
-	m.Set("ConnectsHist", expConnectsHist)
-	m.Set("ConnectsCurrent", expConnectsCurrent)
-	m.Set("ReceivedTotal", expReceivedTotal)
-	m.Set("ReceivedHist", expReceivedHist)
-	m.Set("ErrorsTotal", expErrorsTotal)
-	m.Set("ErrorsHist", expErrorsHist)
-	m.Set("WarnsTotal", expWarnsTotal)
-	m.Set("WarnsHist", expWarnsHist)
-
-	t := time.NewTicker(time.Minute)
-	go metricsTicker(t)
-}

smtpd/utils.go

@@ -2,7 +2,6 @@ package smtpd
 
 import (
 	"bytes"
-	"container/list"
 	"crypto/sha1"
 	"fmt"
 	"io"
@@ -53,18 +52,6 @@ func HashMailboxName(mailbox string) string {
 	return fmt.Sprintf("%x", h.Sum(nil))
 }
 
-// JoinStringList joins a List containing strings by commas
-func JoinStringList(listOfStrings *list.List) string {
-	if listOfStrings.Len() == 0 {
-		return ""
-	}
-	s := make([]string, 0, listOfStrings.Len())
-	for e := listOfStrings.Front(); e != nil; e = e.Next() {
-		s = append(s, e.Value.(string))
-	}
-	return strings.Join(s, ",")
-}
-
 // ValidateDomainPart returns true if the domain part complies to RFC3696, RFC1035
 func ValidateDomainPart(domain string) bool {
 	if len(domain) == 0 {