[v11.0.x] Loki: Remove API restrictions on resource calls (#85201)

Loki: Remove API restrictions on resource calls (#85191)

Loki: Remove API restrictions
(cherry picked from commit c80b31a0d4)

Co-authored-by: Sven Grossmann <sven.grossmann@grafana.com>

pkg/tsdb/loki/loki.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"net/http"
 	"regexp"
-	"strings"
 	"sync"
 	"time"
 
@@ -120,18 +119,7 @@ func (s *Service) CallResource(ctx context.Context, req *backend.CallResourceReq
 
 func callResource(ctx context.Context, req *backend.CallResourceRequest, sender backend.CallResourceResponseSender, dsInfo *datasourceInfo, plog log.Logger, tracer tracing.Tracer) error {
 	url := req.URL
-	// a very basic is-this-url-valid check
-	if req.Method != "GET" {
-		plog.Error("Invalid HTTP method", "method", req.Method)
-		return fmt.Errorf("invalid HTTP method: %s", req.Method)
-	}
-	if (!strings.HasPrefix(url, "labels?")) &&
-		(!strings.HasPrefix(url, "label/")) && // the `/label/$label_name/values` form
-		(!strings.HasPrefix(url, "series?")) &&
-		(!strings.HasPrefix(url, "index/stats?")) {
-		plog.Error("Invalid URL", "url", url)
-		return fmt.Errorf("invalid URL: %s", url)
-	}
+
 	lokiURL := fmt.Sprintf("/loki/api/v1/%s", url)
 
 	ctx, span := tracer.Start(ctx, "datasource.loki.CallResource", trace.WithAttributes(