Add metrics for checkpoint and name changes

Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>

Author: Ganesh Vernekar

pkg/ingester/wal.go

@@ -55,58 +55,89 @@ func (noop) Log(*Record) error {
 // Stop any background WAL processes.
 func (noop) Stop() {}
 
-type wrapper struct {
+type walWrapper struct {
 	cfg      WALConfig
 	ingester *Ingester
 	quit     chan struct{}
 	wait     sync.WaitGroup
 
 	lastWalSegment int
 	wal            *wal.WAL
+
+	// Checkpoint metrics.
+	checkpointDeleteFail    prometheus.Counter
+	checkpointDeleteTotal   prometheus.Counter
+	checkpointCreationFail  prometheus.Counter
+	checkpointCreationTotal prometheus.Counter
 }
 
 func newWAL(cfg WALConfig, ingester *Ingester) (WAL, error) {
 	if !cfg.enabled {
 		return &noop{}, nil
 	}
 
-	var samplesRegistry prometheus.Registerer
+	var walRegistry prometheus.Registerer
 	if cfg.metricsRegisterer != nil {
-		samplesRegistry = prometheus.WrapRegistererWith(prometheus.Labels{"kind": "samples"}, cfg.metricsRegisterer)
+		walRegistry = prometheus.WrapRegistererWith(prometheus.Labels{"kind": "wal"}, cfg.metricsRegisterer)
 	}
-	samples, err := wal.New(util.Logger, samplesRegistry, path.Join(cfg.dir, "samples"), true)
+	tsdbWAL, err := wal.New(util.Logger, walRegistry, path.Join(cfg.dir, "wal"), true)
 	if err != nil {
 		return nil, err
 	}
 
-	w := &wrapper{
+	w := &walWrapper{
 		cfg:      cfg,
 		ingester: ingester,
 		quit:     make(chan struct{}),
-		wal:      samples,
+		wal:      tsdbWAL,
+	}
+
+	w.checkpointDeleteFail = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ingester_checkpoint_deletions_failed_total",
+		Help: "Total number of checkpoint deletions that failed.",
+	})
+	w.checkpointDeleteTotal = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ingester_checkpoint_deletions_total",
+		Help: "Total number of checkpoint deletions attempted.",
+	})
+	w.checkpointCreationFail = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ingester_checkpoint_creations_failed_total",
+		Help: "Total number of checkpoint creations that failed.",
+	})
+	w.checkpointCreationTotal = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "ingester_checkpoint_creations_total",
+		Help: "Total number of checkpoint creations attempted.",
+	})
+	if cfg.metricsRegisterer != nil {
+		cfg.metricsRegisterer.MustRegister(
+			w.checkpointDeleteFail,
+			w.checkpointDeleteTotal,
+			w.checkpointCreationFail,
+			w.checkpointCreationTotal,
+		)
 	}
 
 	w.wait.Add(1)
 	go w.run()
 	return w, nil
 }
 
-func (w *wrapper) Stop() {
+func (w *walWrapper) Stop() {
 	close(w.quit)
 	w.wait.Wait()
 
 	w.wal.Close()
 }
 
-func (w *wrapper) Log(record *Record) error {
+func (w *walWrapper) Log(record *Record) error {
 	buf, err := proto.Marshal(record)
 	if err != nil {
 		return err
 	}
 	return w.wal.Log(buf)
 }
 
-func (w *wrapper) run() {
+func (w *walWrapper) run() {
 	defer w.wait.Done()
 
 	for !w.isStopped() {
@@ -123,7 +154,7 @@ func (w *wrapper) run() {
 	}
 }
 
-func (w *wrapper) isStopped() bool {
+func (w *walWrapper) isStopped() bool {
 	select {
 	case <-w.quit:
 		return true
@@ -134,7 +165,13 @@ func (w *wrapper) isStopped() bool {
 
 const checkpointPrefix = "checkpoint."
 
-func (w *wrapper) checkpoint() error {
+func (w *walWrapper) checkpoint() (err error) {
+	w.checkpointCreationTotal.Inc()
+	defer func() {
+		if err != nil {
+			w.checkpointCreationFail.Inc()
+		}
+	}()
 	_, last, err := w.lastCheckpoint()
 	if err != nil {
 		return err
@@ -201,7 +238,7 @@ func (w *wrapper) checkpoint() error {
 
 // lastCheckpoint returns the directory name and index of the most recent checkpoint.
 // If dir does not contain any checkpoints, -1 is returned as index.
-func (w *wrapper) lastCheckpoint() (string, int, error) {
+func (w *walWrapper) lastCheckpoint() (string, int, error) {
 	files, err := ioutil.ReadDir(w.wal.Dir())
 	if err != nil {
 		return "", -1, err
@@ -226,7 +263,14 @@ func (w *wrapper) lastCheckpoint() (string, int, error) {
 }
 
 // deleteCheckpoints deletes all checkpoints in a directory below a given index.
-func (w *wrapper) deleteCheckpoints(maxIndex int) error {
+func (w *walWrapper) deleteCheckpoints(maxIndex int) (err error) {
+	w.checkpointDeleteTotal.Inc()
+	defer func() {
+		if err != nil {
+			w.checkpointDeleteFail.Inc()
+		}
+	}()
+
 	var errs tsdb_errors.MultiError
 
 	files, err := ioutil.ReadDir(w.wal.Dir())
@@ -248,7 +292,7 @@ func (w *wrapper) deleteCheckpoints(maxIndex int) error {
 	return errs.Err()
 }
 
-func (w *wrapper) checkpointSeries(cp *wal.WAL, userID string, fp model.Fingerprint, series *memorySeries) error {
+func (w *walWrapper) checkpointSeries(cp *wal.WAL, userID string, fp model.Fingerprint, series *memorySeries) error {
 	wireChunks, err := toWireChunks(series.chunkDescs)
 	if err != nil {
 		return err
@@ -268,7 +312,7 @@ func (w *wrapper) checkpointSeries(cp *wal.WAL, userID string, fp model.Fingerpr
 }
 
 // truncateSamples removed the wal from before the checkpoint.
-func (w *wrapper) truncateSamples() error {
+func (w *walWrapper) truncateSamples() error {
 	_, last, err := w.wal.Segments()
 	if err != nil {
 		return err