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77 lines
2.1 KiB
Go
77 lines
2.1 KiB
Go
package image
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import (
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"context"
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"time"
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gocache "github.com/patrickmn/go-cache"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promauto"
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"github.com/grafana/grafana/pkg/services/ngalert/models"
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)
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const (
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namespace = "grafana"
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subsystem = "alerting"
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)
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// CacheService caches images.
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//
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//go:generate mockgen -destination=cache_mock.go -package=image github.com/grafana/grafana/pkg/services/ngalert/image CacheService
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type CacheService interface {
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// Get returns the screenshot for the options or false if a screenshot with these
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// options does not exist.
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Get(ctx context.Context, k string) (models.Image, bool)
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// Set the screenshot for the options. If another screenshot exists with these
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// options then it will be replaced.
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Set(ctx context.Context, k string, image models.Image) error
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}
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// InmemCacheService is an in-mem screenshot cache.
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type InmemCacheService struct {
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cache *gocache.Cache
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cacheHits prometheus.Counter
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cacheMisses prometheus.Counter
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}
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func NewInmemCacheService(expiration time.Duration, r prometheus.Registerer) CacheService {
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return &InmemCacheService{
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cache: gocache.New(expiration, time.Minute),
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cacheHits: promauto.With(r).NewCounter(prometheus.CounterOpts{
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Name: "image_cache_hits_total",
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Namespace: namespace,
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Subsystem: subsystem,
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}),
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cacheMisses: promauto.With(r).NewCounter(prometheus.CounterOpts{
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Name: "image_cache_misses_total",
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Namespace: namespace,
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Subsystem: subsystem,
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}),
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}
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}
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func (s *InmemCacheService) Get(_ context.Context, k string) (models.Image, bool) {
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if v, ok := s.cache.Get(k); ok {
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defer s.cacheHits.Inc()
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return v.(models.Image), true
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}
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defer s.cacheMisses.Inc()
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return models.Image{}, false
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}
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func (s *InmemCacheService) Set(_ context.Context, k string, screenshot models.Image) error {
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s.cache.Set(k, screenshot, 0)
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return nil
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}
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type NoOpCacheService struct{}
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func (s *NoOpCacheService) Get(_ context.Context, _ string) (models.Image, bool) {
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return models.Image{}, false
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}
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func (s *NoOpCacheService) Set(_ context.Context, _ string, _ models.Image) error {
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return nil
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}
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