697 lines
19 KiB
Go
697 lines
19 KiB
Go
// Copyright 2020 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package expfmt
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import (
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"bufio"
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"bytes"
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"fmt"
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"io"
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"math"
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"strconv"
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"strings"
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"google.golang.org/protobuf/types/known/timestamppb"
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"github.com/prometheus/common/model"
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dto "github.com/prometheus/client_model/go"
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)
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type encoderOption struct {
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withCreatedLines bool
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withUnit bool
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}
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type EncoderOption func(*encoderOption)
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// WithCreatedLines is an EncoderOption that configures the OpenMetrics encoder
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// to include _created lines (See
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// https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#counter-1).
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// Created timestamps can improve the accuracy of series reset detection, but
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// come with a bandwidth cost.
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//
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// At the time of writing, created timestamp ingestion is still experimental in
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// Prometheus and need to be enabled with the feature-flag
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// `--feature-flag=created-timestamp-zero-ingestion`, and breaking changes are
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// still possible. Therefore, it is recommended to use this feature with caution.
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func WithCreatedLines() EncoderOption {
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return func(t *encoderOption) {
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t.withCreatedLines = true
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}
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}
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// WithUnit is an EncoderOption enabling a set unit to be written to the output
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// and to be added to the metric name, if it's not there already, as a suffix.
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// Without opting in this way, the unit will not be added to the metric name and,
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// on top of that, the unit will not be passed onto the output, even if it
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// were declared in the *dto.MetricFamily struct, i.e. even if in.Unit !=nil.
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func WithUnit() EncoderOption {
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return func(t *encoderOption) {
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t.withUnit = true
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}
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}
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// MetricFamilyToOpenMetrics converts a MetricFamily proto message into the
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// OpenMetrics text format and writes the resulting lines to 'out'. It returns
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// the number of bytes written and any error encountered. The output will have
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// the same order as the input, no further sorting is performed. Furthermore,
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// this function assumes the input is already sanitized and does not perform any
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// sanity checks. If the input contains duplicate metrics or invalid metric or
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// label names, the conversion will result in invalid text format output.
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//
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// If metric names conform to the legacy validation pattern, they will be placed
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// outside the brackets in the traditional way, like `foo{}`. If the metric name
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// fails the legacy validation check, it will be placed quoted inside the
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// brackets: `{"foo"}`. As stated above, the input is assumed to be santized and
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// no error will be thrown in this case.
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//
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// Similar to metric names, if label names conform to the legacy validation
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// pattern, they will be unquoted as normal, like `foo{bar="baz"}`. If the label
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// name fails the legacy validation check, it will be quoted:
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// `foo{"bar"="baz"}`. As stated above, the input is assumed to be santized and
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// no error will be thrown in this case.
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//
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// This function fulfills the type 'expfmt.encoder'.
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//
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// Note that OpenMetrics requires a final `# EOF` line. Since this function acts
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// on individual metric families, it is the responsibility of the caller to
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// append this line to 'out' once all metric families have been written.
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// Conveniently, this can be done by calling FinalizeOpenMetrics.
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//
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// The output should be fully OpenMetrics compliant. However, there are a few
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// missing features and peculiarities to avoid complications when switching from
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// Prometheus to OpenMetrics or vice versa:
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//
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// - Counters are expected to have the `_total` suffix in their metric name. In
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// the output, the suffix will be truncated from the `# TYPE`, `# HELP` and `# UNIT`
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// lines. A counter with a missing `_total` suffix is not an error. However,
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// its type will be set to `unknown` in that case to avoid invalid OpenMetrics
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// output.
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//
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// - According to the OM specs, the `# UNIT` line is optional, but if populated,
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// the unit has to be present in the metric name as its suffix:
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// (see https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#unit).
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// However, in order to accommodate any potential scenario where such a change in the
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// metric name is not desirable, the users are here given the choice of either explicitly
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// opt in, in case they wish for the unit to be included in the output AND in the metric name
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// as a suffix (see the description of the WithUnit function above),
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// or not to opt in, in case they don't want for any of that to happen.
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//
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// - No support for the following (optional) features: info type,
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// stateset type, gaugehistogram type.
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//
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// - The size of exemplar labels is not checked (i.e. it's possible to create
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// exemplars that are larger than allowed by the OpenMetrics specification).
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//
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// - The value of Counters is not checked. (OpenMetrics doesn't allow counters
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// with a `NaN` value.)
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func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...EncoderOption) (written int, err error) {
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toOM := encoderOption{}
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for _, option := range options {
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option(&toOM)
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}
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name := in.GetName()
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if name == "" {
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return 0, fmt.Errorf("MetricFamily has no name: %s", in)
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}
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// Try the interface upgrade. If it doesn't work, we'll use a
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// bufio.Writer from the sync.Pool.
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w, ok := out.(enhancedWriter)
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if !ok {
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b := bufPool.Get().(*bufio.Writer)
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b.Reset(out)
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w = b
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defer func() {
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bErr := b.Flush()
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if err == nil {
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err = bErr
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}
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bufPool.Put(b)
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}()
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}
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var (
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n int
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metricType = in.GetType()
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compliantName = name
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)
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if metricType == dto.MetricType_COUNTER && strings.HasSuffix(compliantName, "_total") {
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compliantName = name[:len(name)-6]
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}
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if toOM.withUnit && in.Unit != nil && !strings.HasSuffix(compliantName, fmt.Sprintf("_%s", *in.Unit)) {
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compliantName = compliantName + fmt.Sprintf("_%s", *in.Unit)
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}
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// Comments, first HELP, then TYPE.
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if in.Help != nil {
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n, err = w.WriteString("# HELP ")
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written += n
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if err != nil {
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return
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}
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n, err = writeName(w, compliantName)
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written += n
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if err != nil {
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return
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}
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err = w.WriteByte(' ')
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written++
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if err != nil {
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return
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}
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n, err = writeEscapedString(w, *in.Help, true)
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written += n
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if err != nil {
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return
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}
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err = w.WriteByte('\n')
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written++
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if err != nil {
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return
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}
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}
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n, err = w.WriteString("# TYPE ")
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written += n
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if err != nil {
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return
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}
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n, err = writeName(w, compliantName)
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written += n
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if err != nil {
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return
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}
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switch metricType {
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case dto.MetricType_COUNTER:
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if strings.HasSuffix(name, "_total") {
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n, err = w.WriteString(" counter\n")
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} else {
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n, err = w.WriteString(" unknown\n")
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}
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case dto.MetricType_GAUGE:
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n, err = w.WriteString(" gauge\n")
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case dto.MetricType_SUMMARY:
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n, err = w.WriteString(" summary\n")
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case dto.MetricType_UNTYPED:
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n, err = w.WriteString(" unknown\n")
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case dto.MetricType_HISTOGRAM:
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n, err = w.WriteString(" histogram\n")
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default:
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return written, fmt.Errorf("unknown metric type %s", metricType.String())
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}
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written += n
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if err != nil {
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return
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}
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if toOM.withUnit && in.Unit != nil {
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n, err = w.WriteString("# UNIT ")
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written += n
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if err != nil {
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return
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}
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n, err = writeName(w, compliantName)
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written += n
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if err != nil {
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return
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}
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err = w.WriteByte(' ')
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written++
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if err != nil {
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return
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}
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n, err = writeEscapedString(w, *in.Unit, true)
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written += n
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if err != nil {
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return
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}
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err = w.WriteByte('\n')
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written++
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if err != nil {
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return
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}
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}
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var createdTsBytesWritten int
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// Finally the samples, one line for each.
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if metricType == dto.MetricType_COUNTER && strings.HasSuffix(name, "_total") {
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compliantName = compliantName + "_total"
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}
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for _, metric := range in.Metric {
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switch metricType {
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case dto.MetricType_COUNTER:
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if metric.Counter == nil {
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return written, fmt.Errorf(
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"expected counter in metric %s %s", compliantName, metric,
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)
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}
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n, err = writeOpenMetricsSample(
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w, compliantName, "", metric, "", 0,
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metric.Counter.GetValue(), 0, false,
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metric.Counter.Exemplar,
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)
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if toOM.withCreatedLines && metric.Counter.CreatedTimestamp != nil {
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createdTsBytesWritten, err = writeOpenMetricsCreated(w, compliantName, "_total", metric, "", 0, metric.Counter.GetCreatedTimestamp())
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n += createdTsBytesWritten
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}
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case dto.MetricType_GAUGE:
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if metric.Gauge == nil {
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return written, fmt.Errorf(
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"expected gauge in metric %s %s", compliantName, metric,
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)
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}
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n, err = writeOpenMetricsSample(
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w, compliantName, "", metric, "", 0,
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metric.Gauge.GetValue(), 0, false,
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nil,
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)
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case dto.MetricType_UNTYPED:
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if metric.Untyped == nil {
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return written, fmt.Errorf(
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"expected untyped in metric %s %s", compliantName, metric,
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)
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}
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n, err = writeOpenMetricsSample(
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w, compliantName, "", metric, "", 0,
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metric.Untyped.GetValue(), 0, false,
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nil,
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)
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case dto.MetricType_SUMMARY:
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if metric.Summary == nil {
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return written, fmt.Errorf(
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"expected summary in metric %s %s", compliantName, metric,
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)
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}
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for _, q := range metric.Summary.Quantile {
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n, err = writeOpenMetricsSample(
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w, compliantName, "", metric,
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model.QuantileLabel, q.GetQuantile(),
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q.GetValue(), 0, false,
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nil,
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)
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written += n
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if err != nil {
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return
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}
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}
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n, err = writeOpenMetricsSample(
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w, compliantName, "_sum", metric, "", 0,
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metric.Summary.GetSampleSum(), 0, false,
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nil,
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)
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written += n
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if err != nil {
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return
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}
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n, err = writeOpenMetricsSample(
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w, compliantName, "_count", metric, "", 0,
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0, metric.Summary.GetSampleCount(), true,
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nil,
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)
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if toOM.withCreatedLines && metric.Summary.CreatedTimestamp != nil {
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createdTsBytesWritten, err = writeOpenMetricsCreated(w, compliantName, "", metric, "", 0, metric.Summary.GetCreatedTimestamp())
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n += createdTsBytesWritten
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}
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case dto.MetricType_HISTOGRAM:
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if metric.Histogram == nil {
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return written, fmt.Errorf(
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"expected histogram in metric %s %s", compliantName, metric,
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)
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}
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infSeen := false
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for _, b := range metric.Histogram.Bucket {
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n, err = writeOpenMetricsSample(
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w, compliantName, "_bucket", metric,
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model.BucketLabel, b.GetUpperBound(),
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0, b.GetCumulativeCount(), true,
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b.Exemplar,
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)
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written += n
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if err != nil {
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return
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}
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if math.IsInf(b.GetUpperBound(), +1) {
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infSeen = true
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}
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}
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if !infSeen {
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n, err = writeOpenMetricsSample(
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w, compliantName, "_bucket", metric,
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model.BucketLabel, math.Inf(+1),
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0, metric.Histogram.GetSampleCount(), true,
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nil,
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)
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written += n
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if err != nil {
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return
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}
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}
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n, err = writeOpenMetricsSample(
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w, compliantName, "_sum", metric, "", 0,
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metric.Histogram.GetSampleSum(), 0, false,
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nil,
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)
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written += n
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if err != nil {
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return
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}
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n, err = writeOpenMetricsSample(
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w, compliantName, "_count", metric, "", 0,
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0, metric.Histogram.GetSampleCount(), true,
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nil,
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)
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if toOM.withCreatedLines && metric.Histogram.CreatedTimestamp != nil {
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createdTsBytesWritten, err = writeOpenMetricsCreated(w, compliantName, "", metric, "", 0, metric.Histogram.GetCreatedTimestamp())
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n += createdTsBytesWritten
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}
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default:
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return written, fmt.Errorf(
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"unexpected type in metric %s %s", compliantName, metric,
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)
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}
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written += n
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if err != nil {
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return
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}
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}
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return
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}
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// FinalizeOpenMetrics writes the final `# EOF\n` line required by OpenMetrics.
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func FinalizeOpenMetrics(w io.Writer) (written int, err error) {
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return w.Write([]byte("# EOF\n"))
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}
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// writeOpenMetricsSample writes a single sample in OpenMetrics text format to
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// w, given the metric name, the metric proto message itself, optionally an
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// additional label name with a float64 value (use empty string as label name if
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// not required), the value (optionally as float64 or uint64, determined by
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// useIntValue), and optionally an exemplar (use nil if not required). The
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// function returns the number of bytes written and any error encountered.
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func writeOpenMetricsSample(
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w enhancedWriter,
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name, suffix string,
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metric *dto.Metric,
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additionalLabelName string, additionalLabelValue float64,
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floatValue float64, intValue uint64, useIntValue bool,
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exemplar *dto.Exemplar,
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) (int, error) {
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written := 0
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n, err := writeOpenMetricsNameAndLabelPairs(
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w, name+suffix, metric.Label, additionalLabelName, additionalLabelValue,
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)
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written += n
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if err != nil {
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return written, err
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}
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err = w.WriteByte(' ')
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written++
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if err != nil {
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return written, err
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}
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if useIntValue {
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n, err = writeUint(w, intValue)
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} else {
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n, err = writeOpenMetricsFloat(w, floatValue)
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}
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written += n
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if err != nil {
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return written, err
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}
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if metric.TimestampMs != nil {
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err = w.WriteByte(' ')
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written++
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if err != nil {
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return written, err
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}
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// TODO(beorn7): Format this directly without converting to a float first.
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n, err = writeOpenMetricsFloat(w, float64(*metric.TimestampMs)/1000)
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written += n
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if err != nil {
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return written, err
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}
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}
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if exemplar != nil && len(exemplar.Label) > 0 {
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n, err = writeExemplar(w, exemplar)
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written += n
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if err != nil {
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return written, err
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}
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}
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err = w.WriteByte('\n')
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written++
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if err != nil {
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return written, err
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}
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return written, nil
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}
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// writeOpenMetricsNameAndLabelPairs works like writeOpenMetricsSample but
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// formats the float in OpenMetrics style.
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func writeOpenMetricsNameAndLabelPairs(
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w enhancedWriter,
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name string,
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in []*dto.LabelPair,
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additionalLabelName string, additionalLabelValue float64,
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) (int, error) {
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var (
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written int
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separator byte = '{'
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metricInsideBraces = false
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)
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if name != "" {
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// If the name does not pass the legacy validity check, we must put the
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// metric name inside the braces, quoted.
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if !model.IsValidLegacyMetricName(model.LabelValue(name)) {
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metricInsideBraces = true
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err := w.WriteByte(separator)
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written++
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if err != nil {
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return written, err
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}
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separator = ','
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}
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n, err := writeName(w, name)
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written += n
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if err != nil {
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return written, err
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}
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}
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if len(in) == 0 && additionalLabelName == "" {
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if metricInsideBraces {
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err := w.WriteByte('}')
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written++
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if err != nil {
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return written, err
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}
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}
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return written, nil
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}
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for _, lp := range in {
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err := w.WriteByte(separator)
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written++
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if err != nil {
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return written, err
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}
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n, err := writeName(w, lp.GetName())
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written += n
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if err != nil {
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return written, err
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}
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n, err = w.WriteString(`="`)
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written += n
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if err != nil {
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return written, err
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}
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n, err = writeEscapedString(w, lp.GetValue(), true)
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written += n
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if err != nil {
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return written, err
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}
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err = w.WriteByte('"')
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written++
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if err != nil {
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return written, err
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}
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separator = ','
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}
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if additionalLabelName != "" {
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err := w.WriteByte(separator)
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written++
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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
|
|
}
|
|
|
|
// writeOpenMetricsCreated writes the created timestamp for a single time series
|
|
// following OpenMetrics text format to w, given the metric name, the metric proto
|
|
// message itself, optionally a suffix to be removed, e.g. '_total' for counters,
|
|
// an additional label name with a float64 value (use empty string as label name if
|
|
// not required) and the timestamp that represents the created timestamp.
|
|
// The function returns the number of bytes written and any error encountered.
|
|
func writeOpenMetricsCreated(w enhancedWriter,
|
|
name, suffixToTrim string, metric *dto.Metric,
|
|
additionalLabelName string, additionalLabelValue float64,
|
|
createdTimestamp *timestamppb.Timestamp,
|
|
) (int, error) {
|
|
written := 0
|
|
n, err := writeOpenMetricsNameAndLabelPairs(
|
|
w, strings.TrimSuffix(name, suffixToTrim)+"_created", metric.Label, additionalLabelName, additionalLabelValue,
|
|
)
|
|
written += n
|
|
if err != nil {
|
|
return written, err
|
|
}
|
|
|
|
err = w.WriteByte(' ')
|
|
written++
|
|
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(createdTimestamp.AsTime().UnixNano())/1e9)
|
|
written += n
|
|
if err != nil {
|
|
return written, err
|
|
}
|
|
|
|
err = w.WriteByte('\n')
|
|
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 = writeOpenMetricsNameAndLabelPairs(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
|
|
}
|
|
err = (*e).Timestamp.CheckValid()
|
|
if err != nil {
|
|
return written, err
|
|
}
|
|
ts := (*e).Timestamp.AsTime()
|
|
// 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
|
|
}
|