cache.go

package retroproxy

import (
	"fmt"
	"sync"
	"time"

	"go.uber.org/zap"
)

// Cache is an implementation of Storer for an in-memory cache.
type Cache struct {
	logger  *zap.Logger
	tickets map[string]Ticket
	mu      sync.Mutex
}

func NewCache(logger *zap.Logger) *Cache {
	if logger == nil {
		logger = zap.NewNop()
	}
	return &Cache{logger: logger}
}

func (r *Cache) SetTicket(id string, t Ticket) {
	r.mu.Lock()
	defer r.mu.Unlock()
	if r.tickets == nil {
		r.tickets = make(map[string]Ticket)
	}
	r.tickets[id] = t
	r.logger.Debug("ticket set",
		zap.String("ticket_id", id),
		zap.String("ticket", fmt.Sprintf("%+v", t)),
	)
}

func (r *Cache) UseTicket(id string) (Ticket, bool) {
	r.mu.Lock()
	defer r.mu.Unlock()
	t, ok := r.tickets[id]
	if ok {
		delete(r.tickets, id)
		r.logger.Debug("ticket used",
			zap.String("ticket_id", id),
		)
	}
	return t, ok
}

func (r *Cache) DeleteOldTickets(maxDur time.Duration) {
	r.mu.Lock()
	defer r.mu.Unlock()
	now := time.Now()
	for id := range r.tickets {
		deadline := r.tickets[id].IssuedAt.Add(maxDur)
		if now.After(deadline) {
			delete(r.tickets, id)
			r.logger.Debug("old ticket deleted",
				zap.String("ticket_id", id),
			)
		}
	}
}