Elasticsearch: Invalid URL and unsupported protocol should be downstream errors (#100886)

* Invalid URL and unsupported protocol should be downstream errors

* Fix lint

* Change from errors.Is to errors.As

pkg/tsdb/elasticsearch/client/client.go

@@ -135,7 +135,7 @@ func (c *baseClientImpl) executeRequest(method, uriPath, uriQuery string, body [
 	c.logger.Debug("Sending request to Elasticsearch", "url", c.ds.URL)
 	u, err := url.Parse(c.ds.URL)
 	if err != nil {
-		return nil, err
+		return nil, backend.DownstreamError(fmt.Errorf("URL could not be parsed: %w", err))
 	}
 	u.Path = path.Join(u.Path, uriPath)
 	u.RawQuery = uriQuery

pkg/tsdb/elasticsearch/data_query.go

@@ -3,10 +3,13 @@ package elasticsearch
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"net/url"
 	"regexp"
 	"slices"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
@@ -82,6 +85,13 @@ func (e *elasticsearchDataQuery) execute() (*backend.QueryDataResponse, error) {
 		if backend.IsDownstreamHTTPError(err) {
 			err = backend.DownstreamError(err)
 		}
+		var urlErr *url.Error
+		if errors.As(err, &urlErr) {
+			// Unsupported protocol scheme is a common error when the URL is not valid and should be treated as a downstream error
+			if urlErr.Err != nil && strings.HasPrefix(urlErr.Err.Error(), "unsupported protocol scheme") {
+				err = backend.DownstreamError(err)
+			}
+		}
 		response.Responses[e.dataQueries[0].RefID] = backend.ErrorResponseWithErrorSource(err)
 		return response, nil
 	}