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- // Copyright 2021 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.
-
- //go:build !go1.17
- // +build !go1.17
-
- package prometheus
-
- import (
- "runtime"
- "sync"
- "time"
- )
-
- type goCollector struct {
- base baseGoCollector
-
- // ms... are memstats related.
- msLast *runtime.MemStats // Previously collected memstats.
- msLastTimestamp time.Time
- msMtx sync.Mutex // Protects msLast and msLastTimestamp.
- msMetrics memStatsMetrics
- msRead func(*runtime.MemStats) // For mocking in tests.
- msMaxWait time.Duration // Wait time for fresh memstats.
- msMaxAge time.Duration // Maximum allowed age of old memstats.
- }
-
- // NewGoCollector is the obsolete version of collectors.NewGoCollector.
- // See there for documentation.
- //
- // Deprecated: Use collectors.NewGoCollector instead.
- func NewGoCollector() Collector {
- msMetrics := goRuntimeMemStats()
- msMetrics = append(msMetrics, struct {
- desc *Desc
- eval func(*runtime.MemStats) float64
- valType ValueType
- }{
- // This metric is omitted in Go1.17+, see https://github.com/prometheus/client_golang/issues/842#issuecomment-861812034
- desc: NewDesc(
- memstatNamespace("gc_cpu_fraction"),
- "The fraction of this program's available CPU time used by the GC since the program started.",
- nil, nil,
- ),
- eval: func(ms *runtime.MemStats) float64 { return ms.GCCPUFraction },
- valType: GaugeValue,
- })
- return &goCollector{
- base: newBaseGoCollector(),
- msLast: &runtime.MemStats{},
- msRead: runtime.ReadMemStats,
- msMaxWait: time.Second,
- msMaxAge: 5 * time.Minute,
- msMetrics: msMetrics,
- }
- }
-
- // Describe returns all descriptions of the collector.
- func (c *goCollector) Describe(ch chan<- *Desc) {
- c.base.Describe(ch)
- for _, i := range c.msMetrics {
- ch <- i.desc
- }
- }
-
- // Collect returns the current state of all metrics of the collector.
- func (c *goCollector) Collect(ch chan<- Metric) {
- var (
- ms = &runtime.MemStats{}
- done = make(chan struct{})
- )
- // Start reading memstats first as it might take a while.
- go func() {
- c.msRead(ms)
- c.msMtx.Lock()
- c.msLast = ms
- c.msLastTimestamp = time.Now()
- c.msMtx.Unlock()
- close(done)
- }()
-
- // Collect base non-memory metrics.
- c.base.Collect(ch)
-
- timer := time.NewTimer(c.msMaxWait)
- select {
- case <-done: // Our own ReadMemStats succeeded in time. Use it.
- timer.Stop() // Important for high collection frequencies to not pile up timers.
- c.msCollect(ch, ms)
- return
- case <-timer.C: // Time out, use last memstats if possible. Continue below.
- }
- c.msMtx.Lock()
- if time.Since(c.msLastTimestamp) < c.msMaxAge {
- // Last memstats are recent enough. Collect from them under the lock.
- c.msCollect(ch, c.msLast)
- c.msMtx.Unlock()
- return
- }
- // If we are here, the last memstats are too old or don't exist. We have
- // to wait until our own ReadMemStats finally completes. For that to
- // happen, we have to release the lock.
- c.msMtx.Unlock()
- <-done
- c.msCollect(ch, ms)
- }
-
- func (c *goCollector) msCollect(ch chan<- Metric, ms *runtime.MemStats) {
- for _, i := range c.msMetrics {
- ch <- MustNewConstMetric(i.desc, i.valType, i.eval(ms))
- }
- }
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