properly close io.ReadCloser to avoid memory leak (#280)

cleanup

Author: dmitryk-dk

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## tip
 
+* BUGFIX: properly close io.ReadCloser to avoid memory leak. See [this pull request](https://github.com/VictoriaMetrics/victorialogs-datasource/pull/280).
+
 ## v0.16.1
 
 * BUGFIX: fix log context in dashboard view. See [this pull request](https://github.com/VictoriaMetrics/victorialogs-datasource/pull/267). 

pkg/plugin/datasource.go

@@ -231,6 +231,12 @@ func (d *Datasource) streamQuery(ctx context.Context, request *backend.RunStream
 		return err
 	}
 
+	defer func() {
+		if err := r.Close(); err != nil {
+			backend.Logger.Error("failed to close response body", "err", err.Error())
+		}
+	}()
+
 	ch, ok := d.liveModeResponses.Load(request.Path)
 	if !ok {
 		return fmt.Errorf("failed to find the channel for the query: %s", request.Path)
@@ -310,7 +316,7 @@ func (d *Datasource) query(ctx context.Context, _ backend.PluginContext, q *Quer
 
 	defer func() {
 		if err := r.Close(); err != nil {
-			log.DefaultLogger.Error("failed to close response body", "err", err.Error())
+			backend.Logger.Error("failed to close response body", "err", err.Error())
 		}
 	}()