diff --git a/pkg/prometheus/BUILD b/pkg/prometheus/BUILD index ca74c5fc9..5b211d562 100644 --- a/pkg/prometheus/BUILD +++ b/pkg/prometheus/BUILD @@ -11,6 +11,7 @@ go_library( "prometheus.go", "prometheus_verify.go", ], + stateify = False, visibility = ["//:sandbox"], deps = ["//pkg/metric:metric_go_proto"], ) diff --git a/pkg/prometheus/prometheus.go b/pkg/prometheus/prometheus.go index 13d20a946..2f5ed72cc 100644 --- a/pkg/prometheus/prometheus.go +++ b/pkg/prometheus/prometheus.go @@ -18,7 +18,7 @@ package prometheus import ( - "bufio" + "bytes" "errors" "fmt" "io" @@ -63,27 +63,27 @@ type Metric struct { Help string `json:"help"` } -// writeHeaderTo writes the metric comment header to the given writer. -func (m *Metric) writeHeaderTo(w io.Writer, options SnapshotExportOptions) error { +// writeMetricHeaderTo writes the metric comment header to the given writer. +func writeMetricHeaderTo[T io.StringWriter](w T, m *Metric, options SnapshotExportOptions) error { if m.Help != "" { // This writes each string component one by one (rather than using fmt.Sprintf) // in order to avoid allocating strings for each metric. - if _, err := io.WriteString(w, "# HELP "); err != nil { + if _, err := w.WriteString("# HELP "); err != nil { return err } - if _, err := io.WriteString(w, options.ExporterPrefix); err != nil { + if _, err := w.WriteString(options.ExporterPrefix); err != nil { return err } - if _, err := io.WriteString(w, m.Name); err != nil { + if _, err := w.WriteString(m.Name); err != nil { return err } - if _, err := io.WriteString(w, " "); err != nil { + if _, err := w.WriteString(" "); err != nil { return err } if _, err := writeEscapedString(w, m.Help, false); err != nil { return err } - if _, err := io.WriteString(w, "\n"); err != nil { + if _, err := w.WriteString("\n"); err != nil { return err } } @@ -99,22 +99,22 @@ func (m *Metric) writeHeaderTo(w io.Writer, options SnapshotExportOptions) error metricType = "untyped" } if metricType != "" { - if _, err := io.WriteString(w, "# TYPE "); err != nil { + if _, err := w.WriteString("# TYPE "); err != nil { return err } - if _, err := io.WriteString(w, options.ExporterPrefix); err != nil { + if _, err := w.WriteString(options.ExporterPrefix); err != nil { return err } - if _, err := io.WriteString(w, m.Name); err != nil { + if _, err := w.WriteString(m.Name); err != nil { return err } - if _, err := io.WriteString(w, " "); err != nil { + if _, err := w.WriteString(" "); err != nil { return err } - if _, err := io.WriteString(w, metricType); err != nil { + if _, err := w.WriteString(metricType); err != nil { return err } - if _, err := io.WriteString(w, "\n"); err != nil { + if _, err := w.WriteString("\n"); err != nil { return err } } @@ -209,7 +209,7 @@ func (n *Number) ToFloat() float64 { // String returns a string representation of this number. func (n *Number) String() string { var s strings.Builder - if err := n.writeTo(&s); err != nil { + if err := writeNumberTo(&s, n); err != nil { panic(err) } return s.String() @@ -242,14 +242,14 @@ func (n *Number) GreaterThan(other *Number) bool { // WriteInteger writes the given integer to a writer without allocating strings. // //go:nosplit -func WriteInteger(w io.Writer, val int64) (int, error) { +func WriteInteger[T io.StringWriter](w T, val int64) (int, error) { const decimalDigits = "0123456789" if val == 0 { - return io.WriteString(w, decimalDigits[0:1]) + return w.WriteString(decimalDigits[0:1]) } var written int if val < 0 { - n, err := io.WriteString(w, "-") + n, err := w.WriteString("-") written += n if err != nil { return written, err @@ -261,7 +261,7 @@ func WriteInteger(w io.Writer, val int64) (int, error) { } for decimal /= 10; decimal > 0; decimal /= 10 { digit := (val / decimal) % 10 - n, err := io.WriteString(w, decimalDigits[digit:digit+1]) + n, err := w.WriteString(decimalDigits[digit : digit+1]) written += n if err != nil { return written, err @@ -270,9 +270,9 @@ func WriteInteger(w io.Writer, val int64) (int, error) { return written, nil } -// writeTo writes the number to the given writer. +// writeNumberTo writes the number to the given writer. // This only causes heap allocations when the number is a non-zero, non-special float. -func (n *Number) writeTo(w io.Writer) error { +func writeNumberTo[T io.StringWriter](w T, n *Number) error { var s string switch { // Zero case: @@ -296,7 +296,7 @@ func (n *Number) writeTo(w io.Writer) error { default: s = fmt.Sprintf("%f", n.Float) } - _, err := io.WriteString(w, s) + _, err := w.WriteString(s) return err } @@ -413,7 +413,7 @@ type SnapshotExportOptions struct { // per Prometheus spec. It does this without string allocations. // If `quoted` is true, quote characters will surround the string, and quote characters within `s` // will also be escaped. -func writeEscapedString(w io.Writer, s string, quoted bool) (int, error) { +func writeEscapedString[T io.StringWriter](w T, s string, quoted bool) (int, error) { const ( quote = '"' backslash = '\\' @@ -427,7 +427,7 @@ func writeEscapedString(w io.Writer, s string, quoted bool) (int, error) { var n int var err error if quoted { - n, err = io.WriteString(w, quoteStr) + n, err = w.WriteString(quoteStr) written += n if err != nil { return written, err @@ -437,16 +437,16 @@ func writeEscapedString(w io.Writer, s string, quoted bool) (int, error) { switch r { case quote: if quoted { - n, err = io.WriteString(w, escapedQuote) + n, err = w.WriteString(escapedQuote) } else { - n, err = io.WriteString(w, quoteStr) + n, err = w.WriteString(quoteStr) } case backslash: - n, err = io.WriteString(w, escapedBackslash) + n, err = w.WriteString(escapedBackslash) case newline: - n, err = io.WriteString(w, escapedNewline) + n, err = w.WriteString(escapedNewline) default: - n, err = io.WriteString(w, string(r)) + n, err = w.WriteString(string(r)) } written += n if err != nil { @@ -454,7 +454,7 @@ func writeEscapedString(w io.Writer, s string, quoted bool) (int, error) { } } if quoted { - n, err = io.WriteString(w, quoteStr) + n, err = w.WriteString(quoteStr) written += n if err != nil { return written, err @@ -463,17 +463,17 @@ func writeEscapedString(w io.Writer, s string, quoted bool) (int, error) { return written, nil } -// writeMetricPreambleTo writes the metric name to the io.Writer. It may also +// writeMetricPreambleTo writes the metric name to the writer. It may also // write unwritten help and type comments of the metric if they haven't been -// written to the io.Writer yet. -func (d *Data) writeMetricPreambleTo(w io.Writer, options SnapshotExportOptions, metricsWritten map[string]bool) error { +// written to the writer yet. +func writeMetricPreambleTo[T io.StringWriter](w T, d *Data, options SnapshotExportOptions, metricsWritten map[string]bool) error { // Metric header, if we haven't printed it yet. if !metricsWritten[d.Metric.Name] { // Extra newline before each preamble for aesthetic reasons. - if _, err := io.WriteString(w, "\n"); err != nil { + if _, err := w.WriteString("\n"); err != nil { return err } - if err := d.Metric.writeHeaderTo(w, options); err != nil { + if err := writeMetricHeaderTo(w, d.Metric, options); err != nil { return err } metricsWritten[d.Metric.Name] = true @@ -481,11 +481,11 @@ func (d *Data) writeMetricPreambleTo(w io.Writer, options SnapshotExportOptions, // Metric name. if options.ExporterPrefix != "" { - if _, err := io.WriteString(w, options.ExporterPrefix); err != nil { + if _, err := w.WriteString(options.ExporterPrefix); err != nil { return err } } - if _, err := io.WriteString(w, d.Metric.Name); err != nil { + if _, err := w.WriteString(d.Metric.Name); err != nil { return err } return nil @@ -686,9 +686,9 @@ func OrderedLabels(labels ...map[string]string) <-chan LabelOrError { } // writeLabelsTo writes a set of metric labels. -func (d *Data) writeLabelsTo(w io.Writer, extraLabels map[string]string, leLabel *Number) error { +func writeLabelsTo[T io.StringWriter](w T, d *Data, extraLabels map[string]string, leLabel *Number) error { if len(d.Labels)+len(d.ExternalLabels)+len(extraLabels) != 0 || leLabel != nil { - if _, err := io.WriteString(w, "{"); err != nil { + if _, err := w.WriteString("{"); err != nil { return err } var orderedLabels <-chan LabelOrError @@ -708,15 +708,15 @@ func (d *Data) writeLabelsTo(w io.Writer, extraLabels map[string]string, leLabel continue } if !firstLabel { - if _, err := io.WriteString(w, ","); err != nil { + if _, err := w.WriteString(","); err != nil { return err } } firstLabel = false - if _, err := io.WriteString(w, labelOrError.Key); err != nil { + if _, err := w.WriteString(labelOrError.Key); err != nil { return err } - if _, err := io.WriteString(w, "="); err != nil { + if _, err := w.WriteString("="); err != nil { return err } if _, err := writeEscapedString(w, labelOrError.Value, true); err != nil { @@ -726,53 +726,53 @@ func (d *Data) writeLabelsTo(w io.Writer, extraLabels map[string]string, leLabel if foundError != nil { return foundError } - if _, err := io.WriteString(w, "}"); err != nil { + if _, err := w.WriteString("}"); err != nil { return err } } return nil } -// writeMetricLine writes a single line with a single number (val) to w. -func (d *Data) writeMetricLine(w io.Writer, metricSuffix string, val *Number, when time.Time, options SnapshotExportOptions, leLabel *Number, metricsWritten map[string]bool) error { - if err := d.writeMetricPreambleTo(w, options, metricsWritten); err != nil { +// writeMetricLine writes a single Data line with a single number (val) to w. +func writeMetricLine[T io.StringWriter](w T, d *Data, metricSuffix string, val *Number, when time.Time, options SnapshotExportOptions, leLabel *Number, metricsWritten map[string]bool) error { + if err := writeMetricPreambleTo(w, d, options, metricsWritten); err != nil { return err } if metricSuffix != "" { - if _, err := io.WriteString(w, metricSuffix); err != nil { + if _, err := w.WriteString(metricSuffix); err != nil { return err } } - if err := d.writeLabelsTo(w, options.ExtraLabels, leLabel); err != nil { + if err := writeLabelsTo(w, d, options.ExtraLabels, leLabel); err != nil { return err } - if _, err := io.WriteString(w, " "); err != nil { + if _, err := w.WriteString(" "); err != nil { return err } - if err := val.writeTo(w); err != nil { + if err := writeNumberTo(w, val); err != nil { return err } - if _, err := io.WriteString(w, " "); err != nil { + if _, err := w.WriteString(" "); err != nil { return err } if _, err := WriteInteger(w, when.UnixMilli()); err != nil { return err } - if _, err := io.WriteString(w, "\n"); err != nil { + if _, err := w.WriteString("\n"); err != nil { return err } return nil } -// writeTo writes the Data to the given writer in Prometheus format. -func (d *Data) writeTo(w io.Writer, when time.Time, options SnapshotExportOptions, metricsWritten map[string]bool) error { +// writeDataTo writes the Data to the given writer in Prometheus format. +func writeDataTo[T io.StringWriter](w T, d *Data, when time.Time, options SnapshotExportOptions, metricsWritten map[string]bool) error { switch d.Metric.Type { case TypeUntyped, TypeGauge, TypeCounter: - return d.writeMetricLine(w, "", d.Number, when, options, nil, metricsWritten) + return writeMetricLine(w, d, "", d.Number, when, options, nil, metricsWritten) case TypeHistogram: // Write an empty line before and after histograms to easily distinguish them from // other metric lines. - if _, err := io.WriteString(w, "\n"); err != nil { + if _, err := w.WriteString("\n"); err != nil { return err } var numSamples uint64 @@ -780,28 +780,28 @@ func (d *Data) writeTo(w io.Writer, when time.Time, options SnapshotExportOption for _, bucket := range d.HistogramValue.Buckets { numSamples += bucket.Samples samples.Int = int64(numSamples) // Prometheus distribution bucket counts are cumulative. - if err := d.writeMetricLine(w, "_bucket", &samples, when, options, &bucket.UpperBound, metricsWritten); err != nil { + if err := writeMetricLine(w, d, "_bucket", &samples, when, options, &bucket.UpperBound, metricsWritten); err != nil { return err } } - if err := d.writeMetricLine(w, "_sum", &d.HistogramValue.Total, when, options, nil, metricsWritten); err != nil { + if err := writeMetricLine(w, d, "_sum", &d.HistogramValue.Total, when, options, nil, metricsWritten); err != nil { return err } samples.Int = int64(numSamples) - if err := d.writeMetricLine(w, "_count", &samples, when, options, nil, metricsWritten); err != nil { + if err := writeMetricLine(w, d, "_count", &samples, when, options, nil, metricsWritten); err != nil { return err } - if err := d.writeMetricLine(w, "_min", &d.HistogramValue.Min, when, options, nil, metricsWritten); err != nil { + if err := writeMetricLine(w, d, "_min", &d.HistogramValue.Min, when, options, nil, metricsWritten); err != nil { return err } - if err := d.writeMetricLine(w, "_max", &d.HistogramValue.Max, when, options, nil, metricsWritten); err != nil { + if err := writeMetricLine(w, d, "_max", &d.HistogramValue.Max, when, options, nil, metricsWritten); err != nil { return err } - if err := d.writeMetricLine(w, "_ssd", &d.HistogramValue.SumOfSquaredDeviations, when, options, nil, metricsWritten); err != nil { + if err := writeMetricLine(w, d, "_ssd", &d.HistogramValue.SumOfSquaredDeviations, when, options, nil, metricsWritten); err != nil { return err } // Empty line after the histogram. - if _, err := io.WriteString(w, "\n"); err != nil { + if _, err := w.WriteString("\n"); err != nil { return err } return nil @@ -833,37 +833,47 @@ func (s *Snapshot) Add(data ...*Data) *Snapshot { return s } -// countingWriter implements io.Writer, and counts the number of bytes written to it. -// Useful in this file to keep track of total number of bytes without having to plumb this -// everywhere in the writeX() functions in this file. -type countingWriter struct { - w *bufio.Writer - written int -} +const counterWriterBufSize = 32768 -// Write implements io.Writer.Write. -func (w *countingWriter) Write(b []byte) (int, error) { - written, err := w.w.Write(b) - w.written += written - return written, err +// countingWriter implements io.StringWriter, and counts the number of bytes +// written to it. +// Useful in this file to keep track of total number of bytes without having +// to plumb this everywhere in the writeX() functions in this file. +type countingWriter[T io.StringWriter] struct { + buf *bytes.Buffer + underlying T + written int } // WriteString implements io.StringWriter.WriteString. // This avoids going into the slow, allocation-heavy path of io.WriteString. -func (w *countingWriter) WriteString(s string) (int, error) { - written, err := w.w.WriteString(s) +func (w *countingWriter[T]) WriteString(s string) (int, error) { + written, err := w.buf.WriteString(s) w.written += written + if w.buf.Len() >= counterWriterBufSize { + w.Flush() + } return written, err } -// Written returns the number of bytes written to the underlying writer (minus buffered writes). -func (w *countingWriter) Written() int { - return w.written - w.w.Buffered() +func (w *countingWriter[T]) Flush() error { + if w.buf.Len() > 0 { + _, err := w.underlying.WriteString(w.buf.String()) + w.buf.Reset() + return err + } + return nil } -// writeSingleMetric writes the data to the given writer in Prometheus format. +// Written returns the number of bytes written to the underlying writer (minus buffered writes). +func (w *countingWriter[T]) Written() int { + return w.written - w.buf.Len() +} + +// writeSnapshotSingleMetric writes a single metric data from a snapshot to +// the given writer in Prometheus format. // It returns the number of bytes written. -func (s *Snapshot) writeSingleMetric(w io.Writer, options SnapshotExportOptions, metricName string, metricsWritten map[string]bool) error { +func writeSnapshotSingleMetric[T io.StringWriter](w T, s *Snapshot, options SnapshotExportOptions, metricName string, metricsWritten map[string]bool) error { if !strings.HasPrefix(metricName, options.ExporterPrefix) { return nil } @@ -872,29 +882,61 @@ func (s *Snapshot) writeSingleMetric(w io.Writer, options SnapshotExportOptions, if d.Metric.Name != wantMetricName { continue } - if err := d.writeTo(w, s.When, options, metricsWritten); err != nil { + if err := writeDataTo(w, d, s.When, options, metricsWritten); err != nil { return err } } return nil } +// ReusableWriter is a writer that can be reused to efficiently write +// successive snapshots. +type ReusableWriter[T io.StringWriter] struct { + // buf is the reusable buffer used for buffering writes. + // It is reset after each write, but keeps the underlying byte buffer, + // avoiding allocations on successive snapshot writes. + buf bytes.Buffer +} + +// Write writes one or more snapshots to the writer. +// This method may not be used concurrently for the same `ReusableWriter`. +func (rw *ReusableWriter[T]) Write(w T, options ExportOptions, snapshotsToOptions map[*Snapshot]SnapshotExportOptions) (int, error) { + rw.buf.Reset() + cw := &countingWriter[T]{ + buf: &rw.buf, + underlying: w, + } + return write(cw, options, snapshotsToOptions) +} + // Write writes one or more snapshots to the writer. // This ensures same-name metrics across different snapshots are printed together, per spec. -func Write(w io.Writer, options ExportOptions, snapshotsToOptions map[*Snapshot]SnapshotExportOptions) (int, error) { +// If the caller will call `Write` successively for multiple snapshots, it is more efficient +// to use the `ReusableWriter` type instead of this function. +func Write[T io.StringWriter](w T, options ExportOptions, snapshotsToOptions map[*Snapshot]SnapshotExportOptions) (int, error) { + var b bytes.Buffer + // Sane default buffer size. + b.Grow(counterWriterBufSize) + cw := &countingWriter[T]{ + buf: &b, + underlying: w, + } + return write(cw, options, snapshotsToOptions) +} + +func write[T io.StringWriter](cw *countingWriter[T], options ExportOptions, snapshotsToOptions map[*Snapshot]SnapshotExportOptions) (int, error) { if len(snapshotsToOptions) == 0 { return 0, nil } - cw := &countingWriter{w: bufio.NewWriter(w)} if options.CommentHeader != "" { for _, commentLine := range strings.Split(options.CommentHeader, "\n") { - if _, err := io.WriteString(cw, "# "); err != nil { + if _, err := cw.WriteString("# "); err != nil { return cw.Written(), err } - if _, err := io.WriteString(cw, commentLine); err != nil { + if _, err := cw.WriteString(commentLine); err != nil { return cw.Written(), err } - if _, err := io.WriteString(cw, "\n"); err != nil { + if _, err := cw.WriteString("\n"); err != nil { return cw.Written(), err } } @@ -905,7 +947,7 @@ func Write(w io.Writer, options ExportOptions, snapshotsToOptions map[*Snapshot] } switch len(snapshots) { case 1: // Single-snapshot case. - if _, err := io.WriteString(cw, fmt.Sprintf("# Writing data from snapshot containing %d data points taken at %v.\n", len(snapshots[0].Data), snapshots[0].When)); err != nil { + if _, err := cw.WriteString(fmt.Sprintf("# Writing data from snapshot containing %d data points taken at %v.\n", len(snapshots[0].Data), snapshots[0].When)); err != nil { return cw.Written(), err } default: // Multi-snapshot case. @@ -913,16 +955,16 @@ func Write(w io.Writer, options ExportOptions, snapshotsToOptions map[*Snapshot] sort.Slice(snapshots, func(i, j int) bool { return reflect.ValueOf(snapshots[i]).Pointer() < reflect.ValueOf(snapshots[j]).Pointer() }) - if _, err := io.WriteString(cw, fmt.Sprintf("# Writing data from %d snapshots:\n", len(snapshots))); err != nil { + if _, err := cw.WriteString(fmt.Sprintf("# Writing data from %d snapshots:\n", len(snapshots))); err != nil { return cw.Written(), err } for _, snapshot := range snapshots { - if _, err := io.WriteString(cw, fmt.Sprintf("# - Snapshot with %d data points taken at %v: %v\n", len(snapshot.Data), snapshot.When, snapshotsToOptions[snapshot].ExtraLabels)); err != nil { + if _, err := cw.WriteString(fmt.Sprintf("# - Snapshot with %d data points taken at %v: %v\n", len(snapshot.Data), snapshot.When, snapshotsToOptions[snapshot].ExtraLabels)); err != nil { return cw.Written(), err } } } - if _, err := io.WriteString(cw, "\n"); err != nil { + if _, err := cw.WriteString("\n"); err != nil { return cw.Written(), err } if options.MetricsWritten == nil { @@ -942,13 +984,13 @@ func Write(w io.Writer, options ExportOptions, snapshotsToOptions map[*Snapshot] sort.Strings(metricNames) for _, metricName := range metricNames { for _, snapshot := range snapshots { - snapshot.writeSingleMetric(cw, snapshotsToOptions[snapshot], metricName, options.MetricsWritten) + writeSnapshotSingleMetric(cw, snapshot, snapshotsToOptions[snapshot], metricName, options.MetricsWritten) } } - if _, err := io.WriteString(cw, "\n# End of metric data.\n"); err != nil { + if _, err := cw.WriteString("\n# End of metric data.\n"); err != nil { return cw.Written(), err } - if err := cw.w.Flush(); err != nil { + if err := cw.Flush(); err != nil { return cw.Written(), err } return cw.Written(), nil diff --git a/pkg/prometheus/prometheus_test.go b/pkg/prometheus/prometheus_test.go index d1d7ba31a..6cc745d08 100644 --- a/pkg/prometheus/prometheus_test.go +++ b/pkg/prometheus/prometheus_test.go @@ -1170,9 +1170,9 @@ func TestVerifier(t *testing.T) { } } -// shortWriter implements io.Writer but fails after a given number of bytes. +// shortWriter implements io.StringWriter but fails after a given number of bytes. type shortWriter struct { - buf bytes.Buffer + buf strings.Builder size int maxSize int } @@ -1189,9 +1189,9 @@ func (s *shortWriter) String() string { return s.buf.String() } -// Write implements io.Writer.Write. -func (s *shortWriter) Write(b []byte) (n int, err error) { - toWrite := len(b) +// Write implements io.StringWriter.WriteString. +func (s *shortWriter) WriteString(x string) (n int, err error) { + toWrite := len(x) leftToWrite := s.maxSize - s.size if leftToWrite < toWrite { toWrite = leftToWrite @@ -1199,9 +1199,9 @@ func (s *shortWriter) Write(b []byte) (n int, err error) { if toWrite == 0 { return 0, errors.New("writer out of capacity") } - written, err := s.buf.Write(b[:toWrite]) + written, err := s.buf.WriteString(x[:toWrite]) s.size += written - if written == len(b) { + if written == len(x) { return written, err } return written, errors.New("short write") @@ -1696,7 +1696,7 @@ func TestGroupSameNameMetrics(t *testing.T) { // Make sure the data written does parse. // We don't use this result here because the Prometheus library is more permissive than this test. if _, err := (&expfmt.TextParser{}).TextToMetricFamilies(&buf); err != nil { - t.Fatalf("cannot parse data written from snapshots: %v", err) + t.Fatalf("cannot parse data written from snapshots: %v\nraw data:\n%s\n(end of raw data)", err, rawData) } // Verify that we see all metrics, and that each time we see a new one, it's one we haven't seen diff --git a/runsc/metricserver/metricserver.go b/runsc/metricserver/metricserver.go index 72f569fa6..d6e14c967 100644 --- a/runsc/metricserver/metricserver.go +++ b/runsc/metricserver/metricserver.go @@ -19,7 +19,6 @@ import ( "context" "errors" "fmt" - "io" "io/ioutil" "math/rand" "net" @@ -262,6 +261,10 @@ type metricServer struct { // Used to efficiently reallocate a map of the right size during the next export. lastMetricsWrittenSize atomicbitops.Uint32 + // Pool of `prometheus.ReusableWriter`s. Used to avoid large buffer allocations for + // successive snapshots. + promWriterPool sync.Pool + // mu protects the fields below. mu sync.Mutex @@ -613,7 +616,7 @@ func queryMultiSandboxMetrics(ctx context.Context, loadedSandboxes []sandboxLoad } // serveMetrics serves metrics requests. -func (m *metricServer) serveMetrics(w http.ResponseWriter, req *http.Request) httpResult { +func (m *metricServer) serveMetrics(w *httpResponseWriter, req *http.Request) httpResult { ctx, ctxCancel := context.WithTimeout(req.Context(), metricsExportTimeout) defer ctxCancel() @@ -738,10 +741,12 @@ func (m *metricServer) serveMetrics(w http.ResponseWriter, req *http.Request) ht if metricsFilter != "" { commentHeader = fmt.Sprintf("%s (filtered using regular expression: %q)", commentHeader, metricsFilter) } - written, err := prometheus.Write(w, prometheus.ExportOptions{ + promWriter := m.promWriterPool.Get().(*prometheus.ReusableWriter[*httpResponseWriter]) + written, err := promWriter.Write(w, prometheus.ExportOptions{ CommentHeader: commentHeader, MetricsWritten: metricsWritten, }, snapshotsToOptions) + m.promWriterPool.Put(promWriter) if err != nil { if written == 0 { return httpResult{http.StatusServiceUnavailable, err} @@ -761,7 +766,7 @@ func (m *metricServer) serveMetrics(w http.ResponseWriter, req *http.Request) ht // Returns a response prefixed by "runsc-metrics:OK" on success. // Clients can use this to assert that they are talking to the metrics server, as opposed to some // other random HTTP server. -func (m *metricServer) serveHealthCheck(w http.ResponseWriter, req *http.Request) httpResult { +func (m *metricServer) serveHealthCheck(w *httpResponseWriter, req *http.Request) httpResult { m.mu.Lock() defer m.mu.Unlock() if m.shuttingDown { @@ -775,18 +780,18 @@ func (m *metricServer) serveHealthCheck(w http.ResponseWriter, req *http.Request return httpResult{http.StatusBadRequest, fmt.Errorf("this metric server is configured to serve root directory: %s", m.rootDir)} } w.WriteHeader(http.StatusOK) - io.WriteString(w, "runsc-metrics:OK") + w.WriteString("runsc-metrics:OK") return httpOK } // servePID serves the PID of the metric server process. -func (m *metricServer) servePID(w http.ResponseWriter, req *http.Request) httpResult { +func (m *metricServer) servePID(w *httpResponseWriter, req *http.Request) httpResult { m.mu.Lock() defer m.mu.Unlock() if m.shuttingDown { return httpResult{http.StatusServiceUnavailable, errors.New("server is shutting down")} } - io.WriteString(w, strconv.Itoa(m.pid)) + w.WriteString(strconv.Itoa(m.pid)) return httpOK } @@ -823,6 +828,11 @@ func (s *Server) Run(ctx context.Context) error { pidFile: s.PIDFile, exposeProfileEndpoints: s.ExposeProfileEndpoints, allowUnknownRoot: s.AllowUnknownRoot, + promWriterPool: sync.Pool{ + New: func() any { + return &prometheus.ReusableWriter[*httpResponseWriter]{} + }, + }, } conf := s.Config if conf.MetricServer == "" { diff --git a/runsc/metricserver/metricserver_http.go b/runsc/metricserver/metricserver_http.go index 2e861221d..5c9e95d4a 100644 --- a/runsc/metricserver/metricserver_http.go +++ b/runsc/metricserver/metricserver_http.go @@ -16,7 +16,6 @@ package metricserver import ( "errors" - "fmt" "net/http" "runtime" "strings" @@ -38,7 +37,7 @@ type httpResult struct { var httpOK = httpResult{code: http.StatusOK} // serveIndex serves the index page. -func (m *metricServer) serveIndex(w http.ResponseWriter, req *http.Request) httpResult { +func (m *metricServer) serveIndex(w *httpResponseWriter, req *http.Request) httpResult { if req.URL.Path != "/" { if strings.HasPrefix(req.URL.Path, "/metrics?") { // Prometheus's scrape_config.metrics_path takes in a query path and automatically encodes @@ -52,15 +51,40 @@ func (m *metricServer) serveIndex(w http.ResponseWriter, req *http.Request) http } return httpResult{http.StatusNotFound, errors.New("path not found")} } - fmt.Fprintf(w, "runsc metrics") - fmt.Fprintf(w, "

You have reached the runsc metrics server page!

") - fmt.Fprintf(w, `

To see actual metric data, head over to /metrics.

`) - fmt.Fprintf(w, "") + w.WriteString("runsc metrics") + w.WriteString("

You have reached the runsc metrics server page!

") + w.WriteString(`

To see actual metric data, head over to /metrics.

`) + w.WriteString("") return httpOK } +// httpResponseWriter is a ResponseWriter that also implements io.StringWriter. +type httpResponseWriter struct { + resp http.ResponseWriter +} + +// Header implements http.ResponseWriter.Header. +func (w *httpResponseWriter) Header() http.Header { + return w.resp.Header() +} + +// Write implements http.ResponseWriter.Write. +func (w *httpResponseWriter) Write(b []byte) (int, error) { + return w.resp.Write(b) +} + +// WriteHeader implements http.ResponseWriter.WriteHeader. +func (w *httpResponseWriter) WriteHeader(code int) { + w.resp.WriteHeader(code) +} + +// WriteString implements io.StringWriter.WriteString. +func (w *httpResponseWriter) WriteString(s string) (int, error) { + return w.resp.Write([]byte(s)) +} + // logRequest wraps an HTTP handler and adds logging to it. -func logRequest(f func(w http.ResponseWriter, req *http.Request) httpResult) func(w http.ResponseWriter, req *http.Request) { +func logRequest(f func(w *httpResponseWriter, req *http.Request) httpResult) func(w http.ResponseWriter, req *http.Request) { return func(w http.ResponseWriter, req *http.Request) { log.Infof("Request: %s %s", req.Method, req.URL.Path) defer func() { @@ -68,7 +92,7 @@ func logRequest(f func(w http.ResponseWriter, req *http.Request) httpResult) fun log.Warningf("Request: %s %s: Panic:\n%v", req.Method, req.URL.Path, r) } }() - result := f(w, req) + result := f(&httpResponseWriter{resp: w}, req) if result.err != nil { http.Error(w, result.err.Error(), result.code) log.Warningf("Request: %s %s: Failed with HTTP code %d: %v", req.Method, req.URL.Path, result.code, result.err) diff --git a/runsc/metricserver/metricserver_profile.go b/runsc/metricserver/metricserver_profile.go index ebf78819e..c6d538212 100644 --- a/runsc/metricserver/metricserver_profile.go +++ b/runsc/metricserver/metricserver_profile.go @@ -26,7 +26,7 @@ import ( ) // profileCPU returns a CPU profile over HTTP. -func (m *metricServer) profileCPU(w http.ResponseWriter, req *http.Request) httpResult { +func (m *metricServer) profileCPU(w *httpResponseWriter, req *http.Request) httpResult { // Time to finish up profiling and flush out the results to the client. const finishProfilingBuffer = 250 * time.Millisecond @@ -66,7 +66,7 @@ func (m *metricServer) profileCPU(w http.ResponseWriter, req *http.Request) http } // profileHeap returns a heap profile over HTTP. -func (m *metricServer) profileHeap(w http.ResponseWriter, req *http.Request) httpResult { +func (m *metricServer) profileHeap(w *httpResponseWriter, req *http.Request) httpResult { m.mu.Lock() if m.shuttingDown { m.mu.Unlock()