113 lines
3.0 KiB
Go
113 lines
3.0 KiB
Go
package metrics
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import (
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"sync/atomic"
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)
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type CounterSnapshot interface {
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Count() int64
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}
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// Counter hold an int64 value that can be incremented and decremented.
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type Counter interface {
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Clear()
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Dec(int64)
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Inc(int64)
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Snapshot() CounterSnapshot
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}
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// GetOrRegisterCounter returns an existing Counter or constructs and registers
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// a new StandardCounter.
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func GetOrRegisterCounter(name string, r Registry) Counter {
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if nil == r {
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r = DefaultRegistry
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}
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return r.GetOrRegister(name, NewCounter).(Counter)
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}
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// GetOrRegisterCounterForced returns an existing Counter or constructs and registers a
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// new Counter no matter the global switch is enabled or not.
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// Be sure to unregister the counter from the registry once it is of no use to
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// allow for garbage collection.
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func GetOrRegisterCounterForced(name string, r Registry) Counter {
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if nil == r {
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r = DefaultRegistry
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}
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return r.GetOrRegister(name, NewCounterForced).(Counter)
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}
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// NewCounter constructs a new StandardCounter.
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func NewCounter() Counter {
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if !Enabled {
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return NilCounter{}
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}
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return new(StandardCounter)
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}
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// NewCounterForced constructs a new StandardCounter and returns it no matter if
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// the global switch is enabled or not.
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func NewCounterForced() Counter {
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return new(StandardCounter)
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}
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// NewRegisteredCounter constructs and registers a new StandardCounter.
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func NewRegisteredCounter(name string, r Registry) Counter {
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c := NewCounter()
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if nil == r {
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r = DefaultRegistry
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}
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r.Register(name, c)
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return c
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}
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// NewRegisteredCounterForced constructs and registers a new StandardCounter
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// and launches a goroutine no matter the global switch is enabled or not.
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// Be sure to unregister the counter from the registry once it is of no use to
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// allow for garbage collection.
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func NewRegisteredCounterForced(name string, r Registry) Counter {
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c := NewCounterForced()
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if nil == r {
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r = DefaultRegistry
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}
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r.Register(name, c)
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return c
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}
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// counterSnapshot is a read-only copy of another Counter.
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type counterSnapshot int64
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// Count returns the count at the time the snapshot was taken.
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func (c counterSnapshot) Count() int64 { return int64(c) }
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// NilCounter is a no-op Counter.
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type NilCounter struct{}
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func (NilCounter) Clear() {}
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func (NilCounter) Dec(i int64) {}
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func (NilCounter) Inc(i int64) {}
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func (NilCounter) Snapshot() CounterSnapshot { return (*emptySnapshot)(nil) }
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// StandardCounter is the standard implementation of a Counter and uses the
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// sync/atomic package to manage a single int64 value.
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type StandardCounter atomic.Int64
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// Clear sets the counter to zero.
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func (c *StandardCounter) Clear() {
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(*atomic.Int64)(c).Store(0)
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}
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// Dec decrements the counter by the given amount.
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func (c *StandardCounter) Dec(i int64) {
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(*atomic.Int64)(c).Add(-i)
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}
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// Inc increments the counter by the given amount.
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func (c *StandardCounter) Inc(i int64) {
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(*atomic.Int64)(c).Add(i)
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}
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// Snapshot returns a read-only copy of the counter.
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func (c *StandardCounter) Snapshot() CounterSnapshot {
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return counterSnapshot((*atomic.Int64)(c).Load())
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}
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