Image Rendering: Make it work using serve_from_sub_path configured (#23706)

Make rendering work when using serve_from_sub_path and not have rendering.renderer_url configured.

Fixes #21925

pkg/services/rendering/rendering.go

@@ -186,8 +186,13 @@ func (rs *RenderingService) getURL(path string) string {
 		protocol = "https"
 	}
 
+	subPath := ""
+	if rs.Cfg.ServeFromSubPath {
+		subPath = rs.Cfg.AppSubUrl
+	}
+
 	// &render=1 signals to the legacy redirect layer to
-	return fmt.Sprintf("%s://%s:%s/%s&render=1", protocol, rs.domain, setting.HttpPort, path)
+	return fmt.Sprintf("%s://%s:%s%s/%s&render=1", protocol, rs.domain, setting.HttpPort, subPath, path)
 }
 
 func (rs *RenderingService) generateAndStoreRenderKey(orgId, userId int64, orgRole models.RoleType) (string, error) {

pkg/services/rendering/rendering_test.go

+package rendering
+
+import (
+	"testing"
+
+	"github.com/grafana/grafana/pkg/setting"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetUrl(t *testing.T) {
+	path := "render/d-solo/5SdHCadmz/panel-tests-graph?orgId=1&from=1587390211965&to=1587393811965&panelId=5&width=1000&height=500&tz=Europe%2FStockholm"
+	rs := &RenderingService{
+		Cfg: setting.NewCfg(),
+	}
+
+	t.Run("When renderer and callback url configured should return callback url plus path", func(t *testing.T) {
+		rs.Cfg.RendererUrl = "http://localhost:8081/render"
+		rs.Cfg.RendererCallbackUrl = "http://public-grafana.com/"
+		url := rs.getURL(path)
+		require.Equal(t, rs.Cfg.RendererCallbackUrl+path+"&render=1", url)
+	})
+
+	t.Run("When renderer url not configured", func(t *testing.T) {
+		rs.Cfg.RendererUrl = ""
+		rs.domain = "localhost"
+		setting.HttpPort = "3000"
+
+		t.Run("And protocol HTTP configured should return expected path", func(t *testing.T) {
+			rs.Cfg.ServeFromSubPath = false
+			rs.Cfg.AppSubUrl = ""
+			setting.Protocol = setting.HTTP
+			url := rs.getURL(path)
+			require.Equal(t, "http://localhost:3000/"+path+"&render=1", url)
+
+			t.Run("And serve from sub path should return expected path", func(t *testing.T) {
+				rs.Cfg.ServeFromSubPath = true
+				rs.Cfg.AppSubUrl = "/grafana"
+				url := rs.getURL(path)
+				require.Equal(t, "http://localhost:3000/grafana/"+path+"&render=1", url)
+			})
+		})
+
+		t.Run("And protocol HTTPS configured should return expected path", func(t *testing.T) {
+			rs.Cfg.ServeFromSubPath = false
+			rs.Cfg.AppSubUrl = ""
+			setting.Protocol = setting.HTTPS
+			url := rs.getURL(path)
+			require.Equal(t, "https://localhost:3000/"+path+"&render=1", url)
+		})
+
+		t.Run("And protocol HTTP2 configured should return expected path", func(t *testing.T) {
+			rs.Cfg.ServeFromSubPath = false
+			rs.Cfg.AppSubUrl = ""
+			setting.Protocol = setting.HTTP2
+			url := rs.getURL(path)
+			require.Equal(t, "https://localhost:3000/"+path+"&render=1", url)
+		})
+	})
+}