Files
godoxy/internal/metrics/period/entries.go

111 lines
2.7 KiB
Go

package period
import (
"encoding/json"
"time"
"github.com/bytedance/sonic"
)
type Entries[T any] struct {
entries [maxEntries]T
index int
count int
interval time.Duration
lastAdd time.Time
}
const maxEntries = 100
func newEntries[T any](duration time.Duration) *Entries[T] {
interval := max(duration/maxEntries, time.Second)
return &Entries[T]{
interval: interval,
lastAdd: time.Now(),
}
}
func (e *Entries[T]) Add(now time.Time, info T) {
if now.Sub(e.lastAdd) < e.interval {
return
}
e.addWithTime(now, info)
}
// addWithTime adds an entry with a specific timestamp without interval checking.
// This is used internally for reconstructing historical data.
func (e *Entries[T]) addWithTime(timestamp time.Time, info T) {
e.entries[e.index] = info
e.index = (e.index + 1) % maxEntries
if e.count < maxEntries {
e.count++
}
e.lastAdd = timestamp
}
// validateInterval checks if the current interval matches the expected interval for the duration.
// Returns true if valid, false if the interval needs to be recalculated.
func (e *Entries[T]) validateInterval(expectedDuration time.Duration) bool {
expectedInterval := max(expectedDuration/maxEntries, time.Second)
return e.interval == expectedInterval
}
// fixInterval recalculates and sets the correct interval based on the expected duration.
func (e *Entries[T]) fixInterval(expectedDuration time.Duration) {
e.interval = max(expectedDuration/maxEntries, time.Second)
}
func (e *Entries[T]) Get() []T {
if e.count < maxEntries {
return e.entries[:e.count]
}
var res [maxEntries]T
if e.index >= e.count {
copy(res[:], e.entries[:e.count])
} else {
copy(res[:], e.entries[e.index:])
copy(res[e.count-e.index:], e.entries[:e.index])
}
return res[:]
}
type entriesJSON[T any] struct {
Entries []T `json:"entries"`
Interval time.Duration `json:"interval"`
}
func (e *Entries[T]) MarshalJSON() ([]byte, error) {
return sonic.Marshal(entriesJSON[T]{
Entries: e.Get(),
Interval: e.interval,
})
}
func (e *Entries[T]) UnmarshalJSON(data []byte) error {
var v entriesJSON[T]
v.Entries = make([]T, 0, maxEntries)
if err := json.Unmarshal(data, &v); err != nil {
return err
}
if len(v.Entries) == 0 {
return nil
}
entries := v.Entries
if len(entries) > maxEntries {
entries = entries[:maxEntries]
}
// Set the interval first before adding entries.
e.interval = v.Interval
// Add entries with proper time spacing to respect the interval.
now := time.Now()
for i, info := range entries {
// Calculate timestamp based on entry position and interval.
// Most recent entry gets current time, older entries get earlier times.
entryTime := now.Add(-time.Duration(len(entries)-1-i) * e.interval)
e.addWithTime(entryTime, info)
}
return nil
}