From 6601d156be2d066bcf1551d0953cf207f4da6b81 Mon Sep 17 00:00:00 2001
From: James Hillyerd <james@hillyerd.com>
Date: Sat, 31 Mar 2018 12:16:54 -0700
Subject: [PATCH] metric: new pkg refactored from log for #90

---
 pkg/{log/metrics.go => metric/metric.go} | 33 ++++++++++++------------
 pkg/server/smtp/listener.go              | 14 +++++-----
 pkg/storage/retention.go                 | 12 ++++-----
 3 files changed, 30 insertions(+), 29 deletions(-)
 rename pkg/{log/metrics.go => metric/metric.go} (74%)

diff --git a/pkg/log/metrics.go b/pkg/metric/metric.go
similarity index 74%
rename from pkg/log/metrics.go
rename to pkg/metric/metric.go
index c16f1e8..566445d 100644
--- a/pkg/log/metrics.go
+++ b/pkg/metric/metric.go
@@ -1,4 +1,4 @@
-package log
+package metric
 
 import (
 	"container/list"
@@ -7,7 +7,7 @@ import (
 	"time"
 )
 
-// TickerFunc is the type of metrics function accepted by AddTickerFunc
+// TickerFunc is the function signature accepted by AddTickerFunc, will be called once per minute.
 type TickerFunc func()
 
 var tickerFuncChan = make(chan TickerFunc)
@@ -22,10 +22,10 @@ func AddTickerFunc(f TickerFunc) {
 	tickerFuncChan <- f
 }
 
-// PushMetric adds the metric to the end of the list and returns a comma separated string of the
+// Push 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 {
+func Push(history *list.List, ev expvar.Var) string {
 	history.PushBack(ev.String())
 	if history.Len() > 61 {
 		history.Remove(history.Front())
@@ -33,18 +33,7 @@ func PushMetric(history *list.List, ev expvar.Var) string {
 	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, ",")
-}
-
+// metricsTicker calls the current list of TickerFuncs once per minute.
 func metricsTicker() {
 	funcs := make([]TickerFunc, 0)
 	ticker := time.NewTicker(time.Minute)
@@ -60,3 +49,15 @@ func metricsTicker() {
 		}
 	}
 }
+
+// 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, ",")
+}
diff --git a/pkg/server/smtp/listener.go b/pkg/server/smtp/listener.go
index d566e15..e7fd095 100644
--- a/pkg/server/smtp/listener.go
+++ b/pkg/server/smtp/listener.go
@@ -11,6 +11,7 @@ import (
 
 	"github.com/jhillyerd/inbucket/pkg/config"
 	"github.com/jhillyerd/inbucket/pkg/message"
+	"github.com/jhillyerd/inbucket/pkg/metric"
 	"github.com/jhillyerd/inbucket/pkg/policy"
 	"github.com/rs/zerolog/log"
 )
@@ -27,13 +28,12 @@ func init() {
 	m.Set("WarnsTotal", expWarnsTotal)
 	m.Set("WarnsHist", expWarnsHist)
 
-	// TODO #90 move elsewhere
-	// 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))
-	// })
+	metric.AddTickerFunc(func() {
+		expReceivedHist.Set(metric.Push(deliveredHist, expReceivedTotal))
+		expConnectsHist.Set(metric.Push(connectsHist, expConnectsTotal))
+		expErrorsHist.Set(metric.Push(errorsHist, expErrorsTotal))
+		expWarnsHist.Set(metric.Push(warnsHist, expWarnsTotal))
+	})
 }
 
 // Server holds the configuration and state of our SMTP server
diff --git a/pkg/storage/retention.go b/pkg/storage/retention.go
index 6a0b714..166da6b 100644
--- a/pkg/storage/retention.go
+++ b/pkg/storage/retention.go
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/jhillyerd/inbucket/pkg/config"
+	"github.com/jhillyerd/inbucket/pkg/metric"
 	"github.com/rs/zerolog/log"
 )
 
@@ -42,12 +43,11 @@ func init() {
 	rm.Set("RetainedSize", expRetainedSize)
 	rm.Set("SizeHist", expSizeHist)
 
-	// TODO #90 move
-	// log.AddTickerFunc(func() {
-	// 	expRetentionDeletesHist.Set(log.PushMetric(retentionDeletesHist, expRetentionDeletesTotal))
-	// 	expRetainedHist.Set(log.PushMetric(retainedHist, expRetainedCurrent))
-	// 	expSizeHist.Set(log.PushMetric(sizeHist, expRetainedSize))
-	// })
+	metric.AddTickerFunc(func() {
+		expRetentionDeletesHist.Set(metric.Push(retentionDeletesHist, expRetentionDeletesTotal))
+		expRetainedHist.Set(metric.Push(retainedHist, expRetainedCurrent))
+		expSizeHist.Set(metric.Push(sizeHist, expRetainedSize))
+	})
 }
 
 // RetentionScanner looks for messages older than the configured retention period and deletes them.