Backend image rendering as plugin (#11966)

* rendering: headless chrome progress

* renderer: minor change

* grpc: version hell

* updated grpc libs

* wip: minor progess

* rendering: new image rendering plugin is starting to work

* feat: now phantomjs works as well and updated alerting to use new rendering service

* refactor: renamed renderer package and service to rendering to make renderer name less confusing (rendering is internal service that handles the renderer plugin now)

* rendering: now render key is passed and render auth is working in plugin mode

* removed unneeded lines from gitignore

* rendering: now plugin mode supports waiting for all panels to complete rendering

* fix: LastSeenAt fix for render calls, was not set which causes a lot of updates to Last Seen at during rendering, this should fix sqlite db locked issues in seen in previous releases

* change: changed render tz url parameter to use proper timezone name as chrome does not handle UTC offset TZ values

* fix: another update to tz param generation

* renderer: added http mode to renderer service, new ini setting [rendering] server_url

pkg/api/http_server.go

@@ -27,6 +27,7 @@ import (
 	"github.com/grafana/grafana/pkg/models"
 	"github.com/grafana/grafana/pkg/plugins"
 	"github.com/grafana/grafana/pkg/registry"
+	"github.com/grafana/grafana/pkg/services/rendering"
 	"github.com/grafana/grafana/pkg/setting"
 )
 
@@ -42,8 +43,10 @@ type HTTPServer struct {
 	cache         *gocache.Cache
 	httpSrv       *http.Server
 
-	RouteRegister RouteRegister `inject:""`
-	Bus           bus.Bus       `inject:""`
+	RouteRegister RouteRegister     `inject:""`
+	Bus           bus.Bus           `inject:""`
+	RenderService rendering.Service `inject:""`
+	Cfg           *setting.Cfg      `inject:""`
 }
 
 func (hs *HTTPServer) Init() error {
@@ -179,7 +182,7 @@ func (hs *HTTPServer) newMacaron() *macaron.Macaron {
 	hs.mapStatic(m, setting.StaticRootPath, "robots.txt", "robots.txt")
 
 	if setting.ImageUploadProvider == "local" {
-		hs.mapStatic(m, setting.ImagesDir, "", "/public/img/attachments")
+		hs.mapStatic(m, hs.Cfg.ImagesDir, "", "/public/img/attachments")
 	}
 
 	m.Use(macaron.Renderer(macaron.RenderOptions{