Polling in go for caching

poll_cache.go

package cache

import (
	"sync"
	"time"
)

type PollCache[K comparable, V any] struct {
	data     sync.Map
	pollFunc func() map[K]V
	interval time.Duration
}

// NewPollCache initializes a new cache with a polling mechanism
func NewPollCache[K comparable, V any](pollFunc func() map[K]V, interval time.Duration) *PollCache[K, V] {
	pc := &PollCache[K, V]{
		pollFunc: pollFunc,
		interval: interval,
	}
	go pc.startPolling()
	return pc
}

// startPolling continuously updates the cache in a given interval
func (pc *PollCache[K, V]) startPolling() {
	for {
		newData := pc.pollFunc()
		pc.data = sync.Map{} // Reset the map before storing new values
		for k, v := range newData {
			pc.data.Store(k, v)
		}
		time.Sleep(pc.interval)
	}
}

// Get retrieves a value from the cache
func (pc *PollCache[K, V]) Get(key K) (V, bool) {
	val, exists := pc.data.Load(key)
	if exists {
		return val.(V), true
	}
	var zeroValue V
	return zeroValue, false
}

// GetMultiple retrieves multiple values from the cache based on keys
func (pc *PollCache[K, V]) GetMultiple(keys ...K) []V {
	var results []V
	for _, key := range keys {
		if val, exists := pc.Get(key); exists {
			results = append(results, val)
		}
	}
	return results
}

// GetAll retrieves all values from the cache
func (pc *PollCache[K, V]) GetAll() []V {
	var results []V
	pc.data.Range(func(_, value any) bool {
		results = append(results, value.(V))
		return true
	})
	return results
}