From 5794ca8431785cf1fd3a46004d0d13b3ed075016 Mon Sep 17 00:00:00 2001
From: Nicholas Wiersma <nick@wiersma.co.za>
Date: Tue, 7 May 2019 07:14:34 +0200
Subject: [PATCH] Added heartbeat stat (#6)

---
 stats/aggregate_test.go | 12 +++---------
 stats/heartbeat.go      | 26 ++++++++++++++++++++++++++
 stats/heartbeat_test.go | 33 +++++++++++++++++++++++++++++++++
 stats/runtime_test.go   |  2 +-
 4 files changed, 63 insertions(+), 10 deletions(-)
 create mode 100644 stats/heartbeat.go
 create mode 100644 stats/heartbeat_test.go

diff --git a/stats/aggregate_test.go b/stats/aggregate_test.go
index c142464..49e786c 100644
--- a/stats/aggregate_test.go
+++ b/stats/aggregate_test.go
@@ -71,15 +71,13 @@ func TestAggregateStatter_Inc(t *testing.T) {
 	m.On("Close").Return(nil)
 	s := stats.NewAggregateStatter(m, time.Millisecond)
 
-	time.Sleep(time.Millisecond)
-
 	s.Inc("test", 1, 1.0, "foo", "bar")
 	s.Inc("test", 1, 1.0, "foo", "bar")
 	s.Inc("test1", 1, 1.0, "foo", "bar")
 	s.Inc("test", 1, 1.0, "foo1", "bar")
 	s.Inc("rate", 1, 0.1)
 
-	time.Sleep(2 * time.Millisecond)
+	time.Sleep(10 * time.Millisecond)
 
 	_ = s.Close()
 
@@ -94,14 +92,12 @@ func TestAggregateStatter_Gauge(t *testing.T) {
 	m.On("Close").Return(nil)
 	s := stats.NewAggregateStatter(m, time.Millisecond)
 
-	time.Sleep(time.Millisecond)
-
 	s.Gauge("test", 1, 1.0, "foo", "bar")
 	s.Gauge("test", 3, 1.0, "foo", "bar")
 	s.Gauge("test1", 4, 1.0, "foo", "bar")
 	s.Gauge("test", 5, 1.0, "foo1", "bar")
 
-	time.Sleep(2 * time.Millisecond)
+	time.Sleep(10 * time.Millisecond)
 
 	_ = s.Close()
 
@@ -117,15 +113,13 @@ func TestAggregateStatter_Timing(t *testing.T) {
 	m.On("Close").Return(nil)
 	s := stats.NewAggregateStatter(m, time.Millisecond)
 
-	time.Sleep(time.Millisecond)
-
 	s.Timing("test", time.Millisecond, 1.0, "foo", "bar")
 	s.Timing("test", time.Second, 1.0, "foo", "bar")
 	s.Timing("test1", time.Millisecond, 1.0, "foo", "bar")
 	s.Timing("test", time.Millisecond, 1.0, "foo1", "bar")
 	s.Timing("rate", time.Millisecond, 0.1)
 
-	time.Sleep(2 * time.Millisecond)
+	time.Sleep(10 * time.Millisecond)
 
 	_ = s.Close()
 
diff --git a/stats/heartbeat.go b/stats/heartbeat.go
new file mode 100644
index 0000000..c5a5e44
--- /dev/null
+++ b/stats/heartbeat.go
@@ -0,0 +1,26 @@
+package stats
+
+import (
+	"time"
+)
+
+// DefaultHeartbeatInterval is the default heartbeat ticker interval.
+var DefaultHeartbeatInterval = time.Second
+
+// Heartbeat enters a loop, reporting a heartbeat counter periodically.
+func Heartbeat(stats Statter) {
+	HeartbeatEvery(stats, DefaultHeartbeatInterval)
+}
+
+// HeartbeatEvery enters a loop, reporting a heartbeat counter at the specified interval.
+func HeartbeatEvery(stats Statter, t time.Duration) {
+	c := time.Tick(t)
+	for range c {
+		stats.Inc("heartbeat", 1, 1.0)
+	}
+}
+
+// HeartbeatFromStatable is the same as HeartbeatEvery but from context.
+func HeartbeatFromStatable(sable Statable, t time.Duration) {
+	HeartbeatEvery(sable.Statter(), t)
+}
diff --git a/stats/heartbeat_test.go b/stats/heartbeat_test.go
new file mode 100644
index 0000000..471b5d5
--- /dev/null
+++ b/stats/heartbeat_test.go
@@ -0,0 +1,33 @@
+package stats_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/hamba/pkg/stats"
+	"github.com/stretchr/testify/mock"
+)
+
+func TestHeartbeat(t *testing.T) {
+	m := new(MockStats)
+	m.On("Inc", "heartbeat", int64(1), float32(1.0), mock.Anything).Return(nil)
+	stats.DefaultHeartbeatInterval = time.Millisecond
+
+	go stats.Heartbeat(m)
+
+	time.Sleep(100 * time.Millisecond)
+
+	m.AssertCalled(t, "Inc", "heartbeat", int64(1), float32(1.0), mock.Anything)
+}
+
+func TestHeartbeatFromStatable(t *testing.T) {
+	m := new(MockStats)
+	m.On("Inc", "heartbeat", int64(1), float32(1.0), mock.Anything).Return(nil)
+	sable := stats.NewMockStatable(m)
+
+	go stats.HeartbeatFromStatable(sable, time.Millisecond)
+
+	time.Sleep(100 * time.Millisecond)
+
+	m.AssertCalled(t, "Inc", "heartbeat", int64(1), float32(1.0), mock.Anything)
+}
diff --git a/stats/runtime_test.go b/stats/runtime_test.go
index 22e4e3e..aa7b31f 100755
--- a/stats/runtime_test.go
+++ b/stats/runtime_test.go
@@ -21,7 +21,7 @@ func TestRuntime(t *testing.T) {
 	m.AssertCalled(t, "Gauge", "runtime.cpu.goroutines", mock.Anything, mock.Anything, mock.Anything)
 }
 
-func TestRuntimeFromContext(t *testing.T) {
+func TestRuntimeFromStatable(t *testing.T) {
 	m := new(MockStats)
 	m.On("Gauge", mock.Anything, mock.Anything, mock.Anything, mock.Anything).Return(nil)
 	m.On("Timing", mock.Anything, mock.Anything, mock.Anything, mock.Anything).Return(nil)