feat(querier): propagate all known alerting headers (#92873)

pkg/registry/apis/query/header_utils.go

@@ -0,0 +1,35 @@
+package query
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/grafana/grafana/pkg/services/ngalert/models"
+)
+
+// Set of headers that we want to forward to the datasource api servers. Those are used i.e. for
+// cache control or identifying the source of the request.
+//
+// The headers related to grafana alerting can be found here:
+// https://github.com/grafana/grafana-ruler/blob/96e6d4b25c0d973a7615b92b35739511a6fbd72f/pkg/ruler/rulesmanager/ds_query_rule_evaluator.go#L313-L328
+//
+// The usage of strings.ToLower is because the server would convert `FromAlert` to `Fromalert`. So the make matching
+// easier, we just match all headers in lower case.
+var expectedHeaders = map[string]string{
+	strings.ToLower(models.FromAlertHeaderName): models.FromAlertHeaderName,
+	strings.ToLower(models.CacheSkipHeaderName): models.CacheSkipHeaderName,
+	strings.ToLower("X-Rule-Uid"):               "X-Rule-Uid",
+	strings.ToLower("X-Rule-Folder"):            "X-Rule-Folder",
+	strings.ToLower("X-Rule-Source"):            "X-Rule-Source",
+	strings.ToLower("X-Grafana-Org-Id"):         "X-Grafana-Org-Id",
+}
+
+func ExtractKnownHeaders(header http.Header) map[string]string {
+	extractedHeaders := make(map[string]string)
+	for k, v := range header {
+		if headerName, exists := expectedHeaders[strings.ToLower(k)]; exists {
+			extractedHeaders[headerName] = v[0]
+		}
+	}
+	return extractedHeaders
+}