Store: Add resolver service (#57112)

pkg/services/store/resolver/ds_cache.go

@@ -0,0 +1,136 @@
+package resolver
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/grafana/grafana/pkg/plugins/manager/registry"
+	"github.com/grafana/grafana/pkg/services/datasources"
+	"github.com/grafana/grafana/pkg/services/store"
+	"github.com/grafana/grafana/pkg/tsdb/grafanads"
+)
+
+type dsVal struct {
+	InternalID   int64
+	IsDefault    bool
+	Name         string
+	Type         string
+	UID          string
+	PluginExists bool // type exists
+}
+
+type dsCache struct {
+	ds             datasources.DataSourceService
+	pluginRegistry registry.Service
+	cache          map[int64]map[string]*dsVal
+	timestamp      time.Time // across all orgIDs
+	mu             sync.Mutex
+}
+
+func (c *dsCache) refreshCache(ctx context.Context) error {
+	old := c.timestamp
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if c.timestamp != old {
+		return nil // already updated while we waited!
+	}
+
+	cache := make(map[int64]map[string]*dsVal, 0)
+	defaultDS := make(map[int64]*dsVal, 0)
+
+	q := &datasources.GetAllDataSourcesQuery{}
+	err := c.ds.GetAllDataSources(ctx, q)
+	if err != nil {
+		return err
+	}
+
+	for _, ds := range q.Result {
+		val := &dsVal{
+			InternalID: ds.Id,
+			Name:       ds.Name,
+			UID:        ds.Uid,
+			Type:       ds.Type,
+			IsDefault:  ds.IsDefault,
+		}
+		_, ok := c.pluginRegistry.Plugin(ctx, val.Type)
+		val.PluginExists = ok
+
+		orgCache, ok := cache[ds.OrgId]
+		if !ok {
+			orgCache = make(map[string]*dsVal, 0)
+			cache[ds.OrgId] = orgCache
+		}
+
+		orgCache[val.UID] = val
+
+		// Empty string or
+		if val.IsDefault {
+			defaultDS[ds.OrgId] = val
+		}
+	}
+
+	for orgID, orgDSCache := range cache {
+		// modifies the cache we are iterating over?
+		for _, ds := range orgDSCache {
+			// Lookup by internal ID
+			id := fmt.Sprintf("%d", ds.InternalID)
+			_, ok := orgDSCache[id]
+			if !ok {
+				orgDSCache[id] = ds
+			}
+
+			// Lookup by name
+			_, ok = orgDSCache[ds.Name]
+			if !ok {
+				orgDSCache[ds.Name] = ds
+			}
+		}
+
+		// Register the internal builtin grafana datasource
+		gds := &dsVal{
+			Name:         grafanads.DatasourceName,
+			UID:          grafanads.DatasourceUID,
+			Type:         grafanads.DatasourceUID,
+			PluginExists: true,
+		}
+		orgDSCache[gds.UID] = gds
+		ds, ok := defaultDS[orgID]
+		if !ok {
+			ds = gds // use the internal grafana datasource
+		}
+		orgDSCache[""] = ds
+		if orgDSCache["default"] == nil {
+			orgDSCache["default"] = ds
+		}
+	}
+
+	c.cache = cache
+	c.timestamp = getNow()
+	return nil
+}
+
+func (c *dsCache) getDS(ctx context.Context, uid string) (*dsVal, error) {
+	// refresh cache every 1 min
+	if c.cache == nil || c.timestamp.Before(getNow().Add(time.Minute*-1)) {
+		err := c.refreshCache(ctx)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	orgID := store.UserFromContext(ctx).OrgID
+
+	v, ok := c.cache[orgID]
+	if !ok {
+		return nil, nil // org not found
+	}
+	ds, ok := v[uid]
+	if !ok {
+		return nil, nil // data source not found
+	}
+	return ds, nil
+}