Extracting queue interface

pkg/ruler/appender.go

@@ -105,9 +105,9 @@ func (a *RemoteWriteAppendable) onEvict(userID, groupKey string) func() {
 }
 
 func (a *RemoteWriteAppender) Append(_ uint64, l labels.Labels, t int64, v float64) (uint64, error) {
-	a.queue.Append(queueEntry{
-		labels: l,
-		sample: cortexpb.Sample{
+	a.queue.Append(TimeSeriesEntry{
+		Labels: l,
+		Sample: cortexpb.Sample{
 			Value:       v,
 			TimestampMs: t,
 		},

pkg/ruler/appender_test.go

@@ -128,9 +128,9 @@ func TestAppendSample(t *testing.T) {
 	ts := time.Now().Unix()
 	val := 91.2
 
-	sample := queueEntry{
-		labels: labels,
-		sample: cortexpb.Sample{
+	sample := TimeSeriesEntry{
+		Labels: labels,
+		Sample: cortexpb.Sample{
 			Value:       val,
 			TimestampMs: ts,
 		},
@@ -257,8 +257,8 @@ func TestAppenderEvictOldest(t *testing.T) {
 	require.Equal(t, capacity, appender.queue.Length())
 
 	// only two newest samples are kept
-	require.Equal(t, appender.queue.Entries()[0].(queueEntry).sample.Value, 11.3)
-	require.Equal(t, appender.queue.Entries()[1].(queueEntry).sample.Value, 11.4)
+	require.Equal(t, appender.queue.Entries()[0].(TimeSeriesEntry).Sample.Value, 11.3)
+	require.Equal(t, appender.queue.Entries()[1].(TimeSeriesEntry).Sample.Value, 11.4)
 }
 
 // context is created by ruler, passing along details of the rule being executed
@@ -321,7 +321,7 @@ func (c *MockRemoteWriteClient) Name() string { return "" }
 // Endpoint is the remote read or write endpoint for the storage client.
 func (c *MockRemoteWriteClient) Endpoint() string { return "" }
 
-func (c *MockRemoteWriteClient) PrepareRequest(queue *util.EvictingQueue) ([]byte, error) {
+func (c *MockRemoteWriteClient) PrepareRequest(queue util.Queue) ([]byte, error) {
 	args := c.Called(queue)
 	return args.Get(0).([]byte), args.Error(1)
 }

pkg/ruler/remote_write.go

@@ -17,15 +17,15 @@ import (
 
 var UserAgent = fmt.Sprintf("loki-remote-write/%s", build.Version)
 
-type queueEntry struct {
-	labels labels.Labels
-	sample cortexpb.Sample
+type TimeSeriesEntry struct {
+	Labels labels.Labels
+	Sample cortexpb.Sample
 }
 
 type RemoteWriter interface {
 	remote.WriteClient
 
-	PrepareRequest(queue *util.EvictingQueue) ([]byte, error)
+	PrepareRequest(queue util.Queue) ([]byte, error)
 }
 
 type RemoteWriteClient struct {
@@ -62,7 +62,7 @@ func NewRemoteWriter(cfg Config, userID string) (RemoteWriter, error) {
 	}, nil
 }
 
-func (r *RemoteWriteClient) prepare(queue *util.EvictingQueue) error {
+func (r *RemoteWriteClient) prepare(queue util.Queue) error {
 	// reuse slices, resize if they are not big enough
 	if cap(r.labels) < queue.Length() {
 		r.labels = make([]labels.Labels, 0, queue.Length())
@@ -75,21 +75,21 @@ func (r *RemoteWriteClient) prepare(queue *util.EvictingQueue) error {
 	r.samples = r.samples[:0]
 
 	for _, entry := range queue.Entries() {
-		entry, ok := entry.(queueEntry)
+		entry, ok := entry.(TimeSeriesEntry)
 		if !ok {
 			return fmt.Errorf("queue contains invalid entry of type: %T", entry)
 		}
 
-		r.labels = append(r.labels, entry.labels)
-		r.samples = append(r.samples, entry.sample)
+		r.labels = append(r.labels, entry.Labels)
+		r.samples = append(r.samples, entry.Sample)
 	}
 
 	return nil
 }
 
 // PrepareRequest takes the given queue and serializes it into a compressed
 // proto write request that will be sent to Cortex
-func (r *RemoteWriteClient) PrepareRequest(queue *util.EvictingQueue) ([]byte, error) {
+func (r *RemoteWriteClient) PrepareRequest(queue util.Queue) ([]byte, error) {
 	// prepare labels and samples from queue
 	err := r.prepare(queue)
 	if err != nil {

pkg/ruler/remote_write_test.go

@@ -32,7 +32,7 @@ func TestPrepare(t *testing.T) {
 
 	// first start with 10 items
 	for i := 0; i < 10; i++ {
-		queue.Append(queueEntry{labels: lbs, sample: sample})
+		queue.Append(TimeSeriesEntry{Labels: lbs, Sample: sample})
 	}
 	require.Nil(t, client.prepare(queue))
 
@@ -45,7 +45,7 @@ func TestPrepare(t *testing.T) {
 
 	// then resize the internal slices to 100
 	for i := 0; i < 100; i++ {
-		queue.Append(queueEntry{labels: lbs, sample: sample})
+		queue.Append(TimeSeriesEntry{Labels: lbs, Sample: sample})
 	}
 	require.Nil(t, client.prepare(queue))
 
@@ -58,7 +58,7 @@ func TestPrepare(t *testing.T) {
 
 	// then reuse the existing slice (no resize necessary since 5 < 100)
 	for i := 0; i < 5; i++ {
-		queue.Append(queueEntry{labels: lbs, sample: sample})
+		queue.Append(TimeSeriesEntry{Labels: lbs, Sample: sample})
 	}
 	require.Nil(t, client.prepare(queue))
 

pkg/util/queue.go

@@ -0,0 +1,8 @@
+package util
+
+type Queue interface {
+	Append(entry interface{})
+	Entries() []interface{}
+	Length() int
+	Clear()
+}