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bad4f7fec5
* Alerting: Change screenshots to use components This commit changes screenshots to use a number of components instead of a set of functional wrappers. It moves the uploading of screenshots from the screenshot package to the image package so we can re-use the same code for both uploading screenshots and server-side images; SingleFlight from the screenshot package to the image package so we can use it for both taking and uploading the screenshot, where as before it was used just for taking the screenshot; and it also removes the use of a cache because we know that screenshots can be taken at most once per tick of the scheduler.
73 lines
2.2 KiB
Go
73 lines
2.2 KiB
Go
package screenshot
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import (
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"context"
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"fmt"
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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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)
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// CacheService caches screenshots.
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//
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//go:generate mockgen -destination=cache_mock.go -package=screenshot github.com/grafana/grafana/pkg/services/screenshot 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, opts ScreenshotOptions) (*Screenshot, 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, opts ScreenshotOptions, screenshot *Screenshot) 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: "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: "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, opts ScreenshotOptions) (*Screenshot, bool) {
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k := fmt.Sprintf("%s-%d-%s", opts.DashboardUID, opts.PanelID, opts.Theme)
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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.(*Screenshot), true
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}
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defer s.cacheMisses.Inc()
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return nil, false
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}
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func (s *InmemCacheService) Set(_ context.Context, opts ScreenshotOptions, screenshot *Screenshot) error {
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k := fmt.Sprintf("%s-%d-%s", opts.DashboardUID, opts.PanelID, opts.Theme)
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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, _ ScreenshotOptions) (*Screenshot, bool) {
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return nil, false
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}
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func (s *NoOpCacheService) Set(_ context.Context, _ ScreenshotOptions, _ *Screenshot) error {
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return nil
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}
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