changing response_latency buckets some more, making exponential and c…

…onfigurable

cmd/loki-canary/main.go

@@ -30,6 +30,7 @@ func main() {
 	interval := flag.Duration("interval", 1000*time.Millisecond, "Duration between log entries")
 	size := flag.Int("size", 100, "Size in bytes of each log line")
 	wait := flag.Duration("wait", 60*time.Second, "Duration to wait for log entries before reporting them lost")
+	buckets := flag.Int("buckets", 10, "Number of buckets in the response_latency histogram")
 	flag.Parse()
 
 	if *addr == "" {
@@ -51,7 +52,7 @@ func main() {
 
 	_, _ = fmt.Fprintf(os.Stderr, "Connecting to loki at %v, querying for label '%v' with value '%v'\n", u.String(), *lName, *lVal)
 
-	c := comparator.NewComparator(os.Stderr, *wait, 1*time.Second)
+	c := comparator.NewComparator(os.Stderr, *wait, 1*time.Second, *buckets)
 	w := writer.NewWriter(os.Stdout, c, *interval, *size)
 	r := reader.NewReader(os.Stderr, c, u, *user, *pass)
 

pkg/comparator/comparator.go

@@ -36,12 +36,7 @@ var (
 		Name:      "unexpected_entries",
 		Help:      "counts a log entry received which was not expected (e.g. duplicate, received after reported missing)",
 	})
-	responseLatency = promauto.NewHistogram(prometheus.HistogramOpts{
-		Namespace: "loki_canary",
-		Name:      "response_latency",
-		Help:      "is how long it takes for log lines to be returned from Loki in seconds.",
-		Buckets:   []float64{1, 5, 10, 30, 60, 90, 120, 300},
-	})
+	responseLatency prometheus.Histogram
 )
 
 type Comparator struct {
@@ -54,7 +49,7 @@ type Comparator struct {
 	done          chan struct{}
 }
 
-func NewComparator(writer io.Writer, maxWait time.Duration, pruneInterval time.Duration) *Comparator {
+func NewComparator(writer io.Writer, maxWait time.Duration, pruneInterval time.Duration, buckets int) *Comparator {
 	c := &Comparator{
 		w:             writer,
 		entries:       []*time.Time{},
@@ -64,6 +59,13 @@ func NewComparator(writer io.Writer, maxWait time.Duration, pruneInterval time.D
 		done:          make(chan struct{}),
 	}
 
+	responseLatency = promauto.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "loki_canary",
+		Name:      "response_latency",
+		Help:      "is how long it takes for log lines to be returned from Loki in seconds.",
+		Buckets:   prometheus.ExponentialBuckets(0.5, 2, buckets),
+	})
+
 	go c.run()
 
 	return c

pkg/comparator/comparator_test.go

@@ -18,7 +18,7 @@ func TestComparatorEntryReceivedOutOfOrder(t *testing.T) {
 	unexpectedEntries = &mockCounter{}
 
 	actual := &bytes.Buffer{}
-	c := NewComparator(actual, 1*time.Hour, 1*time.Hour)
+	c := NewComparator(actual, 1*time.Hour, 1*time.Hour, 1)
 
 	t1 := time.Now()
 	t2 := t1.Add(1 * time.Second)
@@ -44,6 +44,11 @@ func TestComparatorEntryReceivedOutOfOrder(t *testing.T) {
 	assert.Equal(t, 1, outOfOrderEntries.(*mockCounter).count)
 	assert.Equal(t, 0, unexpectedEntries.(*mockCounter).count)
 	assert.Equal(t, 0, missingEntries.(*mockCounter).count)
+
+	// This avoids a panic on subsequent test execution,
+	// seems ugly but was easy, and multiple instantiations
+	// of the comparator should be an error
+	prometheus.Unregister(responseLatency)
 }
 
 func TestComparatorEntryReceivedNotExpected(t *testing.T) {
@@ -52,7 +57,7 @@ func TestComparatorEntryReceivedNotExpected(t *testing.T) {
 	unexpectedEntries = &mockCounter{}
 
 	actual := &bytes.Buffer{}
-	c := NewComparator(actual, 1*time.Hour, 1*time.Hour)
+	c := NewComparator(actual, 1*time.Hour, 1*time.Hour, 1)
 
 	t1 := time.Now()
 	t2 := t1.Add(1 * time.Second)
@@ -78,6 +83,11 @@ func TestComparatorEntryReceivedNotExpected(t *testing.T) {
 	assert.Equal(t, 0, outOfOrderEntries.(*mockCounter).count)
 	assert.Equal(t, 1, unexpectedEntries.(*mockCounter).count)
 	assert.Equal(t, 0, missingEntries.(*mockCounter).count)
+
+	// This avoids a panic on subsequent test execution,
+	// seems ugly but was easy, and multiple instantiations
+	// of the comparator should be an error
+	prometheus.Unregister(responseLatency)
 }
 
 func TestEntryNeverReceived(t *testing.T) {
@@ -86,7 +96,7 @@ func TestEntryNeverReceived(t *testing.T) {
 	unexpectedEntries = &mockCounter{}
 
 	actual := &bytes.Buffer{}
-	c := NewComparator(actual, 5*time.Millisecond, 2*time.Millisecond)
+	c := NewComparator(actual, 5*time.Millisecond, 2*time.Millisecond, 1)
 
 	t1 := time.Now()
 	t2 := t1.Add(1 * time.Millisecond)
@@ -117,6 +127,11 @@ func TestEntryNeverReceived(t *testing.T) {
 	assert.Equal(t, 0, unexpectedEntries.(*mockCounter).count)
 	assert.Equal(t, 1, missingEntries.(*mockCounter).count)
 
+	// This avoids a panic on subsequent test execution,
+	// seems ugly but was easy, and multiple instantiations
+	// of the comparator should be an error
+	prometheus.Unregister(responseLatency)
+
 }
 
 type mockCounter struct {