micro/debug/buffer/buffer.go
2019-12-01 13:16:43 +00:00

98 lines
1.5 KiB
Go

// Package buffer provides a simple ring buffer for storing local data
package buffer
import (
"sync"
"time"
)
type Buffer struct {
size int
sync.RWMutex
vals []*Entry
}
type Entry struct {
Value interface{}
Timestamp time.Time
}
// New returns a new buffer of the given size
func New(i int) *Buffer {
return &Buffer{
size: i,
}
}
// Put adds a new value to ring buffer
func (b *Buffer) Put(v interface{}) {
b.Lock()
defer b.Unlock()
// append to values
b.vals = append(b.vals, &Entry{
Value: v,
Timestamp: time.Now(),
})
// trim if bigger than size required
if len(b.vals) > b.size {
b.vals = b.vals[1:]
}
}
// Get returns the last n entries
func (b *Buffer) Get(n int) []*Entry {
// reset any invalid values
if n > b.size || n < 0 {
n = b.size
}
b.RLock()
defer b.RUnlock()
// create a delta
delta := b.size - n
// if all the values are less than delta
if len(b.vals) < delta {
return b.vals
}
// return the delta set
return b.vals[delta:]
}
// Return the entries since a specific time
func (b *Buffer) Since(t time.Time) []*Entry {
b.RLock()
defer b.RUnlock()
// return all the values
if t.IsZero() {
return b.vals
}
// if its in the future return nothing
if time.Since(t).Seconds() < 0.0 {
return nil
}
for i, v := range b.vals {
// find the starting point
d := v.Timestamp.Sub(t)
// return the values
if d.Seconds() > 0.0 {
return b.vals[i:]
}
}
return nil
}
// Size returns the size of the ring buffer
func (b *Buffer) Size() int {
return b.size
}