refactor datasource caching

pkg/services/cache/cache.go

@@ -0,0 +1,17 @@
+package cache
+
+import (
+	"time"
+
+	gocache "github.com/patrickmn/go-cache"
+)
+
+type CacheService struct {
+	*gocache.Cache
+}
+
+func New(defaultExpiration, cleanupInterval time.Duration) *CacheService {
+	return &CacheService{
+		Cache: gocache.New(defaultExpiration, cleanupInterval),
+	}
+}

pkg/services/datasources/cache.go

@@ -0,0 +1,49 @@
+package datasources
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/grafana/grafana/pkg/bus"
+	m "github.com/grafana/grafana/pkg/models"
+	"github.com/grafana/grafana/pkg/registry"
+	"github.com/grafana/grafana/pkg/services/cache"
+)
+
+type CacheService interface {
+	GetDatasource(datasourceID int64, user *m.SignedInUser, skipCache bool) (*m.DataSource, error)
+}
+
+type CacheServiceImpl struct {
+	Bus          bus.Bus             `inject:""`
+	CacheService *cache.CacheService `inject:""`
+}
+
+func init() {
+	registry.RegisterService(&CacheServiceImpl{})
+}
+
+func (dc *CacheServiceImpl) Init() error {
+	return nil
+}
+
+func (dc *CacheServiceImpl) GetDatasource(datasourceID int64, user *m.SignedInUser, skipCache bool) (*m.DataSource, error) {
+	cacheKey := fmt.Sprintf("ds-%d", datasourceID)
+
+	if !skipCache {
+		if cached, found := dc.CacheService.Get(cacheKey); found {
+			ds := cached.(*m.DataSource)
+			if ds.OrgId == user.OrgId {
+				return ds, nil
+			}
+		}
+	}
+
+	query := m.GetDataSourceByIdQuery{Id: datasourceID, OrgId: user.OrgId}
+	if err := dc.Bus.Dispatch(&query); err != nil {
+		return nil, err
+	}
+
+	dc.CacheService.Set(cacheKey, query.Result, time.Second*5)
+	return query.Result, nil
+}