AuthZ: add headers for IP range AC checks for data source proxy requests (#81662)

* add a middleware that appens headers for IP range AC to data source proxy requests

* update code

* add tests

* fix a mistake

* add logging

* refactor to reuse code

* small cleanup

* skip the plugins middleware if the header is already set

* skip the plugins middleware if the header is already set

pkg/infra/httpclient/httpclientprovider/grafana_request_id_header_middleware.go

@@ -0,0 +1,34 @@
+package httpclientprovider
+
+import (
+	"net/http"
+
+	sdkhttpclient "github.com/grafana/grafana-plugin-sdk-go/backend/httpclient"
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/services/pluginsintegration/clientmiddleware"
+	"github.com/grafana/grafana/pkg/setting"
+)
+
+const GrafanaRequestIDHeaderMiddlewareName = "grafana-request-id-header-middleware"
+
+func GrafanaRequestIDHeaderMiddleware(cfg *setting.Cfg, logger log.Logger) sdkhttpclient.Middleware {
+	return sdkhttpclient.NamedMiddlewareFunc(GrafanaRequestIDHeaderMiddlewareName, func(opts sdkhttpclient.Options, next http.RoundTripper) http.RoundTripper {
+		return sdkhttpclient.RoundTripperFunc(func(req *http.Request) (*http.Response, error) {
+			if req.Header.Get(clientmiddleware.GrafanaRequestID) != "" {
+				logger.Debug("Request already has a Grafana request ID header", "request_id", req.Header.Get(clientmiddleware.GrafanaRequestID))
+				return next.RoundTrip(req)
+			}
+
+			if !clientmiddleware.IsRequestURLInAllowList(req.URL, cfg) {
+				logger.Debug("Data source URL not among the allow-listed URLs", "url", req.URL.String())
+				return next.RoundTrip(req)
+			}
+
+			for k, v := range clientmiddleware.GetGrafanaRequestIDHeaders(req, cfg, logger) {
+				req.Header.Set(k, v)
+			}
+
+			return next.RoundTrip(req)
+		})
+	})
+}