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|
package logr
import (
"errors"
"github.com/wiggin77/merror"
)
const (
DefMetricsUpdateFreqMillis = 15000 // 15 seconds
)
// Counter is a simple metrics sink that can only increment a value.
// Implementations are external to Logr and provided via `MetricsCollector`.
type Counter interface {
// Inc increments the counter by 1. Use Add to increment it by arbitrary non-negative values.
Inc()
// Add adds the given value to the counter. It panics if the value is < 0.
Add(float64)
}
// Gauge is a simple metrics sink that can receive values and increase or decrease.
// Implementations are external to Logr and provided via `MetricsCollector`.
type Gauge interface {
// Set sets the Gauge to an arbitrary value.
Set(float64)
// Add adds the given value to the Gauge. (The value can be negative, resulting in a decrease of the Gauge.)
Add(float64)
// Sub subtracts the given value from the Gauge. (The value can be negative, resulting in an increase of the Gauge.)
Sub(float64)
}
// MetricsCollector provides a way for users of this Logr package to have metrics pushed
// in an efficient way to any backend, e.g. Prometheus.
// For each target added to Logr, the supplied MetricsCollector will provide a Gauge
// and Counters that will be called frequently as logging occurs.
type MetricsCollector interface {
// QueueSizeGauge returns a Gauge that will be updated by the named target.
QueueSizeGauge(target string) (Gauge, error)
// LoggedCounter returns a Counter that will be incremented by the named target.
LoggedCounter(target string) (Counter, error)
// ErrorCounter returns a Counter that will be incremented by the named target.
ErrorCounter(target string) (Counter, error)
// DroppedCounter returns a Counter that will be incremented by the named target.
DroppedCounter(target string) (Counter, error)
// BlockedCounter returns a Counter that will be incremented by the named target.
BlockedCounter(target string) (Counter, error)
}
// TargetWithMetrics is a target that provides metrics.
type TargetWithMetrics interface {
EnableMetrics(collector MetricsCollector, updateFreqMillis int64) error
}
func (logr *Logr) getMetricsCollector() MetricsCollector {
logr.mux.RLock()
defer logr.mux.RUnlock()
return logr.metrics
}
// SetMetricsCollector enables metrics collection by supplying a MetricsCollector.
// The MetricsCollector provides counters and gauges that are updated by log targets.
func (logr *Logr) SetMetricsCollector(collector MetricsCollector) error {
if collector == nil {
return errors.New("collector cannot be nil")
}
logr.mux.Lock()
logr.metrics = collector
logr.queueSizeGauge, _ = collector.QueueSizeGauge("_logr")
logr.loggedCounter, _ = collector.LoggedCounter("_logr")
logr.errorCounter, _ = collector.ErrorCounter("_logr")
logr.mux.Unlock()
logr.metricsInitOnce.Do(func() {
logr.metricsDone = make(chan struct{})
go logr.startMetricsUpdater()
})
merr := merror.New()
logr.tmux.RLock()
defer logr.tmux.RUnlock()
for _, target := range logr.targets {
if tm, ok := target.(TargetWithMetrics); ok {
if err := tm.EnableMetrics(collector, logr.MetricsUpdateFreqMillis); err != nil {
merr.Append(err)
}
}
}
return merr.ErrorOrNil()
}
func (logr *Logr) setQueueSizeGauge(val float64) {
logr.mux.RLock()
defer logr.mux.RUnlock()
if logr.queueSizeGauge != nil {
logr.queueSizeGauge.Set(val)
}
}
func (logr *Logr) incLoggedCounter() {
logr.mux.RLock()
defer logr.mux.RUnlock()
if logr.loggedCounter != nil {
logr.loggedCounter.Inc()
}
}
func (logr *Logr) incErrorCounter() {
logr.mux.RLock()
defer logr.mux.RUnlock()
if logr.errorCounter != nil {
logr.errorCounter.Inc()
}
}
|
