diff options
Diffstat (limited to 'vendor/github.com/prometheus/common/expfmt/text_create.go')
| -rw-r--r-- | vendor/github.com/prometheus/common/expfmt/text_create.go | 468 |
1 files changed, 468 insertions, 0 deletions
diff --git a/vendor/github.com/prometheus/common/expfmt/text_create.go b/vendor/github.com/prometheus/common/expfmt/text_create.go new file mode 100644 index 000000000..8e473d0fe --- /dev/null +++ b/vendor/github.com/prometheus/common/expfmt/text_create.go @@ -0,0 +1,468 @@ +// Copyright 2014 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 ( + "bytes" + "fmt" + "io" + "math" + "strconv" + "strings" + "sync" + + "github.com/prometheus/common/model" + + dto "github.com/prometheus/client_model/go" +) + +// enhancedWriter has all the enhanced write functions needed here. bytes.Buffer +// implements it. +type enhancedWriter interface { + io.Writer + WriteRune(r rune) (n int, err error) + WriteString(s string) (n int, err error) + WriteByte(c byte) error +} + +const ( + initialBufSize = 512 + initialNumBufSize = 24 +) + +var ( + bufPool = sync.Pool{ + New: func() interface{} { + return bytes.NewBuffer(make([]byte, 0, initialBufSize)) + }, + } + numBufPool = sync.Pool{ + New: func() interface{} { + b := make([]byte, 0, initialNumBufSize) + return &b + }, + } +) + +// MetricFamilyToText converts a MetricFamily proto message into 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 method fulfills the type 'prometheus.encoder'. +func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err error) { + // Fail-fast checks. + if len(in.Metric) == 0 { + return 0, fmt.Errorf("MetricFamily has no metrics: %s", in) + } + 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 + // bytes.Buffer from the sync.Pool and write out its content to out in a + // single go in the end. + w, ok := out.(enhancedWriter) + if !ok { + b := bufPool.Get().(*bytes.Buffer) + b.Reset() + w = b + defer func() { + bWritten, bErr := out.Write(b.Bytes()) + written = bWritten + if err == nil { + err = bErr + } + bufPool.Put(b) + }() + } + + var n int + + // Comments, first HELP, then TYPE. + if in.Help != nil { + n, err = w.WriteString("# HELP ") + written += n + if err != nil { + return + } + n, err = w.WriteString(name) + written += n + if err != nil { + return + } + err = w.WriteByte(' ') + written++ + if err != nil { + return + } + n, err = writeEscapedString(w, *in.Help, false) + 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(name) + written += n + if err != nil { + return + } + metricType := in.GetType() + switch metricType { + case dto.MetricType_COUNTER: + n, err = w.WriteString(" counter\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(" untyped\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, + ) + } + n, err = writeSample( + w, name, "", metric, "", 0, + metric.Counter.GetValue(), + ) + case dto.MetricType_GAUGE: + if metric.Gauge == nil { + return written, fmt.Errorf( + "expected gauge in metric %s %s", name, metric, + ) + } + n, err = writeSample( + w, name, "", metric, "", 0, + metric.Gauge.GetValue(), + ) + case dto.MetricType_UNTYPED: + if metric.Untyped == nil { + return written, fmt.Errorf( + "expected untyped in metric %s %s", name, metric, + ) + } + n, err = writeSample( + w, name, "", metric, "", 0, + metric.Untyped.GetValue(), + ) + 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 = writeSample( + w, name, "", metric, + model.QuantileLabel, q.GetQuantile(), + q.GetValue(), + ) + written += n + if err != nil { + return + } + } + n, err = writeSample( + w, name, "_sum", metric, "", 0, + metric.Summary.GetSampleSum(), + ) + written += n + if err != nil { + return + } + n, err = writeSample( + w, name, "_count", metric, "", 0, + float64(metric.Summary.GetSampleCount()), + ) + 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 = writeSample( + w, name, "_bucket", metric, + model.BucketLabel, b.GetUpperBound(), + float64(b.GetCumulativeCount()), + ) + written += n + if err != nil { + return + } + if math.IsInf(b.GetUpperBound(), +1) { + infSeen = true + } + } + if !infSeen { + n, err = writeSample( + w, name, "_bucket", metric, + model.BucketLabel, math.Inf(+1), + float64(metric.Histogram.GetSampleCount()), + ) + written += n + if err != nil { + return + } + } + n, err = writeSample( + w, name, "_sum", metric, "", 0, + metric.Histogram.GetSampleSum(), + ) + written += n + if err != nil { + return + } + n, err = writeSample( + w, name, "_count", metric, "", 0, + float64(metric.Histogram.GetSampleCount()), + ) + default: + return written, fmt.Errorf( + "unexpected type in metric %s %s", name, metric, + ) + } + written += n + if err != nil { + return + } + } + return +} + +// writeSample writes a single sample in 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), and +// the value. The function returns the number of bytes written and any error +// encountered. +func writeSample( + w enhancedWriter, + name, suffix string, + metric *dto.Metric, + additionalLabelName string, additionalLabelValue float64, + value float64, +) (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 = writeLabelPairs( + w, metric.Label, additionalLabelName, additionalLabelValue, + ) + written += n + if err != nil { + return written, err + } + err = w.WriteByte(' ') + written++ + if err != nil { + return written, err + } + n, err = writeFloat(w, value) + written += n + if err != nil { + return written, err + } + if metric.TimestampMs != nil { + err = w.WriteByte(' ') + written++ + if err != nil { + return written, err + } + n, err = writeInt(w, *metric.TimestampMs) + written += n + if err != nil { + return written, err + } + } + err = w.WriteByte('\n') + written++ + if err != nil { + return written, err + } + return written, nil +} + +// writeLabelPairs converts a slice of LabelPair proto messages plus the +// explicitly given additional label pair into text formatted as required by the +// text format and writes it to 'w'. An empty slice in combination with an empty +// string 'additionalLabelName' results in nothing being written. Otherwise, the +// label pairs are written, escaped as required by the text format, and enclosed +// in '{...}'. The function returns the number of bytes written and any error +// encountered. +func writeLabelPairs( + 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 = writeFloat(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 +} + +// writeEscapedString replaces '\' by '\\', new line character by '\n', and - if +// includeDoubleQuote is true - '"' by '\"'. +var ( + escaper = strings.NewReplacer("\\", `\\`, "\n", `\n`) + quotedEscaper = strings.NewReplacer("\\", `\\`, "\n", `\n`, "\"", `\"`) +) + +func writeEscapedString(w enhancedWriter, v string, includeDoubleQuote bool) (int, error) { + if includeDoubleQuote { + return quotedEscaper.WriteString(w, v) + } else { + return escaper.WriteString(w, v) + } +} + +// writeFloat is equivalent to fmt.Fprint with a float64 argument but hardcodes +// a few common cases for increased efficiency. For non-hardcoded cases, it uses +// strconv.AppendFloat to avoid allocations, similar to writeInt. +func writeFloat(w enhancedWriter, f float64) (int, error) { + switch { + case f == 1: + return 1, w.WriteByte('1') + case f == 0: + return 1, w.WriteByte('0') + case f == -1: + return w.WriteString("-1") + 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) + written, err := w.Write(*bp) + numBufPool.Put(bp) + return written, err + } +} + +// writeInt is equivalent to fmt.Fprint with an int64 argument but uses +// strconv.AppendInt with a byte slice taken from a sync.Pool to avoid +// allocations. +func writeInt(w enhancedWriter, i int64) (int, error) { + bp := numBufPool.Get().(*[]byte) + *bp = strconv.AppendInt((*bp)[:0], i, 10) + written, err := w.Write(*bp) + numBufPool.Put(bp) + return written, err +} |