src/go/plugin/go.d/pkg/metrics/counter.go
// SPDX-License-Identifier: GPL-3.0-or-later
package metrics
import (
"errors"
"github.com/netdata/netdata/go/plugins/plugin/go.d/pkg/stm"
)
type (
// Counter is a Metric that represents a single numerical bits that only ever
// goes up. That implies that it cannot be used to count items whose number can
// also go down, e.g. the number of currently running goroutines. Those
// "counters" are represented by Gauges.
//
// A Counter is typically used to count requests served, tasks completed, errors
// occurred, etc.
Counter struct {
valInt int64
valFloat float64
}
// CounterVec is a Collector that bundles a set of Counters which have different values for their names.
// This is used if you want to count the same thing partitioned by various dimensions
// (e.g. number of HTTP requests, partitioned by response code and method).
//
// Create instances with NewCounterVec.
CounterVec map[string]*Counter
)
var (
_ stm.Value = Counter{}
_ stm.Value = CounterVec{}
)
// WriteTo writes its value into given map.
func (c Counter) WriteTo(rv map[string]int64, key string, mul, div int) {
rv[key] = int64(c.Value() * float64(mul) / float64(div))
}
// Value gets current counter.
func (c Counter) Value() float64 {
return float64(c.valInt) + c.valFloat
}
// Inc increments the counter by 1. Use Add to increment it by arbitrary
// non-negative values.
func (c *Counter) Inc() {
c.valInt++
}
// Add adds the given bits to the counter. It panics if the value is < 0.
func (c *Counter) Add(v float64) {
if v < 0 {
panic(errors.New("counter cannot decrease in value"))
}
val := int64(v)
if float64(val) == v {
c.valInt += val
return
}
c.valFloat += v
}
// NewCounterVec creates a new CounterVec
func NewCounterVec() CounterVec {
return CounterVec{}
}
// WriteTo writes its value into given map.
func (c CounterVec) WriteTo(rv map[string]int64, key string, mul, div int) {
for name, value := range c {
rv[key+"_"+name] = int64(value.Value() * float64(mul) / float64(div))
}
}
// Get gets counter instance by name
func (c CounterVec) Get(name string) *Counter {
item, _ := c.GetP(name)
return item
}
// GetP gets counter instance by name
func (c CounterVec) GetP(name string) (counter *Counter, ok bool) {
counter, ok = c[name]
if ok {
return
}
counter = &Counter{}
c[name] = counter
return
}