140 lines
2.8 KiB
Go
140 lines
2.8 KiB
Go
// Copyright (c) 2013, Prometheus Team
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// All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package prometheus
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import (
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"encoding/json"
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"fmt"
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"sync"
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"code.google.com/p/goprotobuf/proto"
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dto "github.com/prometheus/client_model/go"
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"github.com/prometheus/client_golang/model"
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)
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// A gauge metric merely provides an instantaneous representation of a scalar
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// value or an accumulation. For instance, if one wants to expose the current
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// temperature or the hitherto bandwidth used, this would be the metric for such
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// circumstances.
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type Gauge interface {
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Metric
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Set(labels map[string]string, value float64) float64
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}
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type gaugeVector struct {
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Labels map[string]string `json:"labels"`
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Value float64 `json:"value"`
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}
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func NewGauge() Gauge {
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return &gauge{
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values: map[uint64]*gaugeVector{},
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}
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}
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type gauge struct {
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mutex sync.RWMutex
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values map[uint64]*gaugeVector
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}
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func (metric *gauge) String() string {
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formatString := "[Gauge %s]"
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metric.mutex.RLock()
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defer metric.mutex.RUnlock()
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return fmt.Sprintf(formatString, metric.values)
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}
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func (metric *gauge) Set(labels map[string]string, value float64) float64 {
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if labels == nil {
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labels = blankLabelsSingleton
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}
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signature := model.LabelValuesToSignature(labels)
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metric.mutex.Lock()
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defer metric.mutex.Unlock()
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if original, ok := metric.values[signature]; ok {
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original.Value = value
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} else {
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metric.values[signature] = &gaugeVector{
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Labels: labels,
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Value: value,
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}
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}
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return value
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}
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func (metric *gauge) Reset(labels map[string]string) {
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signature := model.LabelValuesToSignature(labels)
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metric.mutex.Lock()
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defer metric.mutex.Unlock()
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delete(metric.values, signature)
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}
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func (metric *gauge) ResetAll() {
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metric.mutex.Lock()
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defer metric.mutex.Unlock()
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for key, value := range metric.values {
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for label := range value.Labels {
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delete(value.Labels, label)
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}
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delete(metric.values, key)
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}
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}
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func (metric *gauge) MarshalJSON() ([]byte, error) {
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metric.mutex.RLock()
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defer metric.mutex.RUnlock()
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values := make([]*gaugeVector, 0, len(metric.values))
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for _, value := range metric.values {
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values = append(values, value)
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}
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return json.Marshal(map[string]interface{}{
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typeKey: gaugeTypeValue,
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valueKey: values,
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})
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}
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func (metric *gauge) dumpChildren(f *dto.MetricFamily) {
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metric.mutex.RLock()
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defer metric.mutex.RUnlock()
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f.Type = dto.MetricType_GAUGE.Enum()
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for _, child := range metric.values {
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c := &dto.Gauge{
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Value: proto.Float64(child.Value),
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}
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m := &dto.Metric{
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Gauge: c,
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}
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for name, value := range child.Labels {
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p := &dto.LabelPair{
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Name: proto.String(name),
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Value: proto.String(value),
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}
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m.Label = append(m.Label, p)
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}
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f.Metric = append(f.Metric, m)
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}
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}
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