diff options
Diffstat (limited to 'vendor/github.com/prometheus/common/expfmt/openmetrics_create.go')
| -rw-r--r-- | vendor/github.com/prometheus/common/expfmt/openmetrics_create.go | 527 |
1 files changed, 527 insertions, 0 deletions
diff --git a/vendor/github.com/prometheus/common/expfmt/openmetrics_create.go b/vendor/github.com/prometheus/common/expfmt/openmetrics_create.go new file mode 100644 index 000000000..8a9313a3b --- /dev/null +++ b/vendor/github.com/prometheus/common/expfmt/openmetrics_create.go @@ -0,0 +1,527 @@ +// Copyright 2020 The Prometheus Authors +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package expfmt + +import ( + "bufio" + "bytes" + "fmt" + "io" + "math" + "strconv" + "strings" + + "github.com/golang/protobuf/ptypes" + "github.com/prometheus/common/model" + + dto "github.com/prometheus/client_model/go" +) + +// MetricFamilyToOpenMetrics converts a MetricFamily proto message into the +// OpenMetrics text format and writes the resulting lines to 'out'. It returns +// the number of bytes written and any error encountered. The output will have +// the same order as the input, no further sorting is performed. Furthermore, +// this function assumes the input is already sanitized and does not perform any +// sanity checks. If the input contains duplicate metrics or invalid metric or +// label names, the conversion will result in invalid text format output. +// +// This function fulfills the type 'expfmt.encoder'. +// +// Note that OpenMetrics requires a final `# EOF` line. Since this function acts +// on individual metric families, it is the responsibility of the caller to +// append this line to 'out' once all metric families have been written. +// Conveniently, this can be done by calling FinalizeOpenMetrics. +// +// The output should be fully OpenMetrics compliant. However, there are a few +// missing features and peculiarities to avoid complications when switching from +// Prometheus to OpenMetrics or vice versa: +// +// - Counters are expected to have the `_total` suffix in their metric name. In +// the output, the suffix will be truncated from the `# TYPE` and `# HELP` +// line. A counter with a missing `_total` suffix is not an error. However, +// its type will be set to `unknown` in that case to avoid invalid OpenMetrics +// output. +// +// - No support for the following (optional) features: `# UNIT` line, `_created` +// line, info type, stateset type, gaugehistogram type. +// +// - The size of exemplar labels is not checked (i.e. it's possible to create +// exemplars that are larger than allowed by the OpenMetrics specification). +// +// - The value of Counters is not checked. (OpenMetrics doesn't allow counters +// with a `NaN` value.) +func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily) (written int, err error) { + name := in.GetName() + if name == "" { + return 0, fmt.Errorf("MetricFamily has no name: %s", in) + } + + // Try the interface upgrade. If it doesn't work, we'll use a + // bufio.Writer from the sync.Pool. + w, ok := out.(enhancedWriter) + if !ok { + b := bufPool.Get().(*bufio.Writer) + b.Reset(out) + w = b + defer func() { + bErr := b.Flush() + if err == nil { + err = bErr + } + bufPool.Put(b) + }() + } + + var ( + n int + metricType = in.GetType() + shortName = name + ) + if metricType == dto.MetricType_COUNTER && strings.HasSuffix(shortName, "_total") { + shortName = name[:len(name)-6] + } + + // Comments, first HELP, then TYPE. + if in.Help != nil { + n, err = w.WriteString("# HELP ") + written += n + if err != nil { + return + } + n, err = w.WriteString(shortName) + written += n + if err != nil { + return + } + err = w.WriteByte(' ') + written++ + if err != nil { + return + } + n, err = writeEscapedString(w, *in.Help, true) + written += n + if err != nil { + return + } + err = w.WriteByte('\n') + written++ + if err != nil { + return + } + } + n, err = w.WriteString("# TYPE ") + written += n + if err != nil { + return + } + n, err = w.WriteString(shortName) + written += n + if err != nil { + return + } + switch metricType { + case dto.MetricType_COUNTER: + if strings.HasSuffix(name, "_total") { + n, err = w.WriteString(" counter\n") + } else { + n, err = w.WriteString(" unknown\n") + } + case dto.MetricType_GAUGE: + n, err = w.WriteString(" gauge\n") + case dto.MetricType_SUMMARY: + n, err = w.WriteString(" summary\n") + case dto.MetricType_UNTYPED: + n, err = w.WriteString(" unknown\n") + case dto.MetricType_HISTOGRAM: + n, err = w.WriteString(" histogram\n") + default: + return written, fmt.Errorf("unknown metric type %s", metricType.String()) + } + written += n + if err != nil { + return + } + + // Finally the samples, one line for each. + for _, metric := range in.Metric { + switch metricType { + case dto.MetricType_COUNTER: + if metric.Counter == nil { + return written, fmt.Errorf( + "expected counter in metric %s %s", name, metric, + ) + } + // Note that we have ensured above that either the name + // ends on `_total` or that the rendered type is + // `unknown`. Therefore, no `_total` must be added here. + n, err = writeOpenMetricsSample( + w, name, "", metric, "", 0, + metric.Counter.GetValue(), 0, false, + metric.Counter.Exemplar, + ) + case dto.MetricType_GAUGE: + if metric.Gauge == nil { + return written, fmt.Errorf( + "expected gauge in metric %s %s", name, metric, + ) + } + n, err = writeOpenMetricsSample( + w, name, "", metric, "", 0, + metric.Gauge.GetValue(), 0, false, + nil, + ) + case dto.MetricType_UNTYPED: + if metric.Untyped == nil { + return written, fmt.Errorf( + "expected untyped in metric %s %s", name, metric, + ) + } + n, err = writeOpenMetricsSample( + w, name, "", metric, "", 0, + metric.Untyped.GetValue(), 0, false, + nil, + ) + case dto.MetricType_SUMMARY: + if metric.Summary == nil { + return written, fmt.Errorf( + "expected summary in metric %s %s", name, metric, + ) + } + for _, q := range metric.Summary.Quantile { + n, err = writeOpenMetricsSample( + w, name, "", metric, + model.QuantileLabel, q.GetQuantile(), + q.GetValue(), 0, false, + nil, + ) + written += n + if err != nil { + return + } + } + n, err = writeOpenMetricsSample( + w, name, "_sum", metric, "", 0, + metric.Summary.GetSampleSum(), 0, false, + nil, + ) + written += n + if err != nil { + return + } + n, err = writeOpenMetricsSample( + w, name, "_count", metric, "", 0, + 0, metric.Summary.GetSampleCount(), true, + nil, + ) + case dto.MetricType_HISTOGRAM: + if metric.Histogram == nil { + return written, fmt.Errorf( + "expected histogram in metric %s %s", name, metric, + ) + } + infSeen := false + for _, b := range metric.Histogram.Bucket { + n, err = writeOpenMetricsSample( + w, name, "_bucket", metric, + model.BucketLabel, b.GetUpperBound(), + 0, b.GetCumulativeCount(), true, + b.Exemplar, + ) + written += n + if err != nil { + return + } + if math.IsInf(b.GetUpperBound(), +1) { + infSeen = true + } + } + if !infSeen { + n, err = writeOpenMetricsSample( + w, name, "_bucket", metric, + model.BucketLabel, math.Inf(+1), + 0, metric.Histogram.GetSampleCount(), true, + nil, + ) + written += n + if err != nil { + return + } + } + n, err = writeOpenMetricsSample( + w, name, "_sum", metric, "", 0, + metric.Histogram.GetSampleSum(), 0, false, + nil, + ) + written += n + if err != nil { + return + } + n, err = writeOpenMetricsSample( + w, name, "_count", metric, "", 0, + 0, metric.Histogram.GetSampleCount(), true, + nil, + ) + default: + return written, fmt.Errorf( + "unexpected type in metric %s %s", name, metric, + ) + } + written += n + if err != nil { + return + } + } + return +} + +// FinalizeOpenMetrics writes the final `# EOF\n` line required by OpenMetrics. +func FinalizeOpenMetrics(w io.Writer) (written int, err error) { + return w.Write([]byte("# EOF\n")) +} + +// writeOpenMetricsSample writes a single sample in OpenMetrics text format to +// w, given the metric name, the metric proto message itself, optionally an +// additional label name with a float64 value (use empty string as label name if +// not required), the value (optionally as float64 or uint64, determined by +// useIntValue), and optionally an exemplar (use nil if not required). The +// function returns the number of bytes written and any error encountered. +func writeOpenMetricsSample( + w enhancedWriter, + name, suffix string, + metric *dto.Metric, + additionalLabelName string, additionalLabelValue float64, + floatValue float64, intValue uint64, useIntValue bool, + exemplar *dto.Exemplar, +) (int, error) { + var written int + n, err := w.WriteString(name) + written += n + if err != nil { + return written, err + } + if suffix != "" { + n, err = w.WriteString(suffix) + written += n + if err != nil { + return written, err + } + } + n, err = writeOpenMetricsLabelPairs( + w, metric.Label, additionalLabelName, additionalLabelValue, + ) + written += n + if err != nil { + return written, err + } + err = w.WriteByte(' ') + written++ + if err != nil { + return written, err + } + if useIntValue { + n, err = writeUint(w, intValue) + } else { + n, err = writeOpenMetricsFloat(w, floatValue) + } + written += n + if err != nil { + return written, err + } + if metric.TimestampMs != nil { + err = w.WriteByte(' ') + written++ + if err != nil { + return written, err + } + // TODO(beorn7): Format this directly without converting to a float first. + n, err = writeOpenMetricsFloat(w, float64(*metric.TimestampMs)/1000) + written += n + if err != nil { + return written, err + } + } + if exemplar != nil { + n, err = writeExemplar(w, exemplar) + written += n + if err != nil { + return written, err + } + } + err = w.WriteByte('\n') + written++ + if err != nil { + return written, err + } + return written, nil +} + +// writeOpenMetricsLabelPairs works like writeOpenMetrics but formats the float +// in OpenMetrics style. +func writeOpenMetricsLabelPairs( + w enhancedWriter, + in []*dto.LabelPair, + additionalLabelName string, additionalLabelValue float64, +) (int, error) { + if len(in) == 0 && additionalLabelName == "" { + return 0, nil + } + var ( + written int + separator byte = '{' + ) + for _, lp := range in { + err := w.WriteByte(separator) + written++ + if err != nil { + return written, err + } + n, err := w.WriteString(lp.GetName()) + written += n + if err != nil { + return written, err + } + n, err = w.WriteString(`="`) + written += n + if err != nil { + return written, err + } + n, err = writeEscapedString(w, lp.GetValue(), true) + written += n + if err != nil { + return written, err + } + err = w.WriteByte('"') + written++ + if err != nil { + return written, err + } + separator = ',' + } + if additionalLabelName != "" { + err := w.WriteByte(separator) + written++ + if err != nil { + return written, err + } + n, err := w.WriteString(additionalLabelName) + written += n + if err != nil { + return written, err + } + n, err = w.WriteString(`="`) + written += n + if err != nil { + return written, err + } + n, err = writeOpenMetricsFloat(w, additionalLabelValue) + written += n + if err != nil { + return written, err + } + err = w.WriteByte('"') + written++ + if err != nil { + return written, err + } + } + err := w.WriteByte('}') + written++ + if err != nil { + return written, err + } + return written, nil +} + +// writeExemplar writes the provided exemplar in OpenMetrics format to w. The +// function returns the number of bytes written and any error encountered. +func writeExemplar(w enhancedWriter, e *dto.Exemplar) (int, error) { + written := 0 + n, err := w.WriteString(" # ") + written += n + if err != nil { + return written, err + } + n, err = writeOpenMetricsLabelPairs(w, e.Label, "", 0) + written += n + if err != nil { + return written, err + } + err = w.WriteByte(' ') + written++ + if err != nil { + return written, err + } + n, err = writeOpenMetricsFloat(w, e.GetValue()) + written += n + if err != nil { + return written, err + } + if e.Timestamp != nil { + err = w.WriteByte(' ') + written++ + if err != nil { + return written, err + } + ts, err := ptypes.Timestamp((*e).Timestamp) + if err != nil { + return written, err + } + // TODO(beorn7): Format this directly from components of ts to + // avoid overflow/underflow and precision issues of the float + // conversion. + n, err = writeOpenMetricsFloat(w, float64(ts.UnixNano())/1e9) + written += n + if err != nil { + return written, err + } + } + return written, nil +} + +// writeOpenMetricsFloat works like writeFloat but appends ".0" if the resulting +// number would otherwise contain neither a "." nor an "e". +func writeOpenMetricsFloat(w enhancedWriter, f float64) (int, error) { + switch { + case f == 1: + return w.WriteString("1.0") + case f == 0: + return w.WriteString("0.0") + case f == -1: + return w.WriteString("-1.0") + case math.IsNaN(f): + return w.WriteString("NaN") + case math.IsInf(f, +1): + return w.WriteString("+Inf") + case math.IsInf(f, -1): + return w.WriteString("-Inf") + default: + bp := numBufPool.Get().(*[]byte) + *bp = strconv.AppendFloat((*bp)[:0], f, 'g', -1, 64) + if !bytes.ContainsAny(*bp, "e.") { + *bp = append(*bp, '.', '0') + } + written, err := w.Write(*bp) + numBufPool.Put(bp) + return written, err + } +} + +// writeUint is like writeInt just for uint64. +func writeUint(w enhancedWriter, u uint64) (int, error) { + bp := numBufPool.Get().(*[]byte) + *bp = strconv.AppendUint((*bp)[:0], u, 10) + written, err := w.Write(*bp) + numBufPool.Put(bp) + return written, err +} |