Quick fix for leaks.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

CHANGELOG.md

@@ -16,7 +16,7 @@ We use *breaking* word for marking changes that are not backward compatible (rel
 - [#2665](https://github.com/thanos-io/thanos/pull/2665) Swift: fix issue with missing Content-Type HTTP headers.
 - [#2800](https://github.com/thanos-io/thanos/pull/2800) Query: Fix handling of `--web.external-prefix` and `--web.route-prefix`
 - [#2834](https://github.com/thanos-io/thanos/pull/2834) Query: Fix rendered JSON state value for rules and alerts should be in lowercase
-- [#2866](https://github.com/thanos-io/thanos/pull/2866) Receive: Fixed a leak on receive Store API Series, which was leaking on errors.
+- [#2866](https://github.com/thanos-io/thanos/pull/2866) Receive,Querier: Fixed leaks on receive and qwuerier Store API Series, which were leaking on errors.
 
 ### Changed
 

pkg/store/multitsdb.go

@@ -90,9 +90,9 @@ type tenantSeriesSetServer struct {
 
 	ctx context.Context
 
-	warnCh warnSender
-	recv   chan *storepb.Series
-	cur    *storepb.Series
+	directCh directSender
+	recv     chan *storepb.Series
+	cur      *storepb.Series
 
 	err    error
 	tenant string
@@ -103,13 +103,13 @@ type tenantSeriesSetServer struct {
 func newTenantSeriesSetServer(
 	ctx context.Context,
 	tenant string,
-	warnCh warnSender,
+	directCh directSender,
 ) *tenantSeriesSetServer {
 	return &tenantSeriesSetServer{
-		ctx:    ctx,
-		tenant: tenant,
-		warnCh: warnCh,
-		recv:   make(chan *storepb.Series),
+		ctx:      ctx,
+		tenant:   tenant,
+		directCh: directCh,
+		recv:     make(chan *storepb.Series),
 	}
 }
 
@@ -120,27 +120,30 @@ func (s *tenantSeriesSetServer) Series(store storepb.StoreServer, r *storepb.Ser
 	tracing.DoInSpan(s.ctx, "multitsdb_tenant_series", func(_ context.Context) {
 		err = store.Series(r, s)
 	})
-
 	if err != nil {
 		if r.PartialResponseDisabled || r.PartialResponseStrategy == storepb.PartialResponseStrategy_ABORT {
 			s.err = errors.Wrapf(err, "get series for tenant %s", s.tenant)
 		} else {
 			// Consistently prefix tenant specific warnings as done in various other places.
 			err = errors.New(prefixTenantWarning(s.tenant, err.Error()))
-			s.warnCh.send(storepb.NewWarnSeriesResponse(err))
+			s.directCh.send(storepb.NewWarnSeriesResponse(err))
 		}
 	}
-
 	close(s.recv)
 }
 
 func (s *tenantSeriesSetServer) Send(r *storepb.SeriesResponse) error {
 	series := r.GetSeries()
-	chunks := make([]storepb.AggrChunk, len(series.Chunks))
-	copy(chunks, series.Chunks)
-	s.recv <- &storepb.Series{
-		Labels: series.Labels,
-		Chunks: chunks,
+	if series == nil {
+		// Proxy non series responses directly to client
+		s.directCh.send(r)
+		return nil
+	}
+	// For series, pass it to our AggChunkSeriesSet.
+	select {
+	case <-s.ctx.Done():
+		return s.ctx.Err()
+	case s.recv <- series:
 	}
 	return nil
 }
@@ -157,37 +160,39 @@ func (s *tenantSeriesSetServer) At() ([]storepb.Label, []storepb.AggrChunk) {
 	return s.cur.Labels, s.cur.Chunks
 }
 
-func (s *tenantSeriesSetServer) Err() error {
-	return s.err
-}
+func (s *tenantSeriesSetServer) Err() error { return s.err }
 
 // Series returns all series for a requested time range and label matcher. The
 // returned data may exceed the requested time bounds. The data returned may
 // have been read and merged from multiple underlying TSDBStore instances.
 func (s *MultiTSDBStore) Series(r *storepb.SeriesRequest, srv storepb.Store_SeriesServer) error {
+	span, ctx := tracing.StartSpan(srv.Context(), "multitsdb_series")
+	defer span.Finish()
+
 	stores := s.tsdbStores()
 	if len(stores) == 0 {
 		return nil
 	}
 
-	var (
-		g, gctx   = errgroup.WithContext(srv.Context())
-		span, ctx = tracing.StartSpan(gctx, "multitsdb_series")
-		// Allow to buffer max 10 series response.
-		// Each might be quite large (multi chunk long series given by sidecar).
-		respSender, respRecv, closeFn = newRespCh(gctx, 10)
-	)
-	defer span.Finish()
+	g, gctx := errgroup.WithContext(ctx)
+
+	// Allow to buffer max 10 series response.
+	// Each might be quite large (multi chunk long series given by sidecar).
+	respSender, respCh := newCancellableRespChannel(gctx, 10)
 
 	g.Go(func() error {
+		// This go routine is responsible for calling store's Series concurrently. Merged results
+		// are passed to respCh and sent concurrently to client (if buffer of 10 have room).
+		// When this go routine finishes or is cancelled, respCh channel is closed.
+
 		var (
 			seriesSet []storepb.SeriesSet
 			wg        = &sync.WaitGroup{}
 		)
 
 		defer func() {
 			wg.Wait()
-			closeFn()
+			close(respCh)
 		}()
 
 		for tenant, store := range stores {
@@ -214,13 +219,16 @@ func (s *MultiTSDBStore) Series(r *storepb.SeriesRequest, srv storepb.Store_Seri
 		}
 		return mergedSet.Err()
 	})
-
-	for resp := range respRecv {
-		if err := srv.Send(resp); err != nil {
-			return status.Error(codes.Unknown, errors.Wrap(err, "send series response").Error())
+	g.Go(func() error {
+		// Go routine for gathering merged responses and sending them over to client. It stops when
+		// respCh channel is closed OR on error from client.
+		for resp := range respCh {
+			if err := srv.Send(resp); err != nil {
+				return status.Error(codes.Unknown, errors.Wrap(err, "send series response").Error())
+			}
 		}
-	}
-
+		return nil
+	})
 	return g.Wait()
 }
 

pkg/store/proxy.go

@@ -184,18 +184,23 @@ func mergeLabels(a []storepb.Label, b labels.Labels) []storepb.Label {
 	return res
 }
 
-type ctxRespSender struct {
+// cancellableRespSender is a response channel that does need to be exhausted on cancel.
+type cancellableRespSender struct {
 	ctx context.Context
 	ch  chan<- *storepb.SeriesResponse
 }
 
-func newRespCh(ctx context.Context, buffer int) (*ctxRespSender, <-chan *storepb.SeriesResponse, func()) {
+func newCancellableRespChannel(ctx context.Context, buffer int) (*cancellableRespSender, chan *storepb.SeriesResponse) {
 	respCh := make(chan *storepb.SeriesResponse, buffer)
-	return &ctxRespSender{ctx: ctx, ch: respCh}, respCh, func() { close(respCh) }
+	return &cancellableRespSender{ctx: ctx, ch: respCh}, respCh
 }
 
-func (s ctxRespSender) send(r *storepb.SeriesResponse) {
-	s.ch <- r
+// send or returns on cancel.
+func (s cancellableRespSender) send(r *storepb.SeriesResponse) {
+	select {
+	case <-s.ctx.Done():
+	case s.ch <- r:
+	}
 }
 
 // Series returns all series for a requested time range and label matcher. Requested series are taken from other
@@ -213,15 +218,17 @@ func (s *ProxyStore) Series(r *storepb.SeriesRequest, srv storepb.Store_SeriesSe
 		return status.Error(codes.InvalidArgument, errors.New("no matchers specified (excluding external labels)").Error())
 	}
 
-	var (
-		g, gctx = errgroup.WithContext(srv.Context())
+	g, gctx := errgroup.WithContext(srv.Context())
 
-		// Allow to buffer max 10 series response.
-		// Each might be quite large (multi chunk long series given by sidecar).
-		respSender, respRecv, closeFn = newRespCh(gctx, 10)
-	)
+	// Allow to buffer max 10 series response.
+	// Each might be quite large (multi chunk long series given by sidecar).
+	respSender, respCh := newCancellableRespChannel(gctx, 10)
 
 	g.Go(func() error {
+		// This go routine is responsible for calling store's Series concurrently. Merged results
+		// are passed to respCh and sent concurrently to client (if buffer of 10 have room).
+		// When this go routine finishes or is cancelled, respCh channel is closed.
+
 		var (
 			seriesSet      []storepb.SeriesSet
 			storeDebugMsgs []string
@@ -239,7 +246,7 @@ func (s *ProxyStore) Series(r *storepb.SeriesRequest, srv storepb.Store_SeriesSe
 
 		defer func() {
 			wg.Wait()
-			closeFn()
+			close(respCh)
 		}()
 
 		for _, st := range s.stores() {
@@ -306,21 +313,25 @@ func (s *ProxyStore) Series(r *storepb.SeriesRequest, srv storepb.Store_SeriesSe
 		}
 		return mergedSet.Err()
 	})
-
-	for resp := range respRecv {
-		if err := srv.Send(resp); err != nil {
-			return status.Error(codes.Unknown, errors.Wrap(err, "send series response").Error())
+	g.Go(func() error {
+		// Go routine for gathering merged responses and sending them over to client. It stops when
+		// respCh channel is closed OR on error from client.
+		for resp := range respCh {
+			if err := srv.Send(resp); err != nil {
+				return status.Error(codes.Unknown, errors.Wrap(err, "send series response").Error())
+			}
 		}
-	}
-
+		return nil
+	})
 	if err := g.Wait(); err != nil {
+		// TODO(bwplotka): Replace with request logger.
 		level.Error(s.logger).Log("err", err)
 		return err
 	}
 	return nil
 }
 
-type warnSender interface {
+type directSender interface {
 	send(*storepb.SeriesResponse)
 }
 
@@ -331,7 +342,7 @@ type streamSeriesSet struct {
 	logger log.Logger
 
 	stream storepb.Store_SeriesClient
-	warnCh warnSender
+	warnCh directSender
 
 	currSeries *storepb.Series
 	recvCh     chan *storepb.Series
@@ -367,7 +378,7 @@ func startStreamSeriesSet(
 	closeSeries context.CancelFunc,
 	wg *sync.WaitGroup,
 	stream storepb.Store_SeriesClient,
-	warnCh warnSender,
+	warnCh directSender,
 	name string,
 	partialResponse bool,
 	responseTimeout time.Duration,