Chore: Improve rendering logging (#21008)

Moving info log from phantomjs to rendering service 
so it's logged for all kinds of renderers.
Add debug log for image renderer plugin and remote 
renderer.

pkg/services/rendering/rendering.go

@@ -3,11 +3,12 @@ package rendering
 import (
 	"context"
 	"fmt"
-	plugin "github.com/hashicorp/go-plugin"
 	"net/url"
 	"os"
 	"path/filepath"
 
+	plugin "github.com/hashicorp/go-plugin"
+
 	pluginModel "github.com/grafana/grafana-plugin-model/go/renderer"
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/middleware"
@@ -59,6 +60,7 @@ func (rs *RenderingService) Init() error {
 
 func (rs *RenderingService) Run(ctx context.Context) error {
 	if rs.Cfg.RendererUrl != "" {
+		rs.log = rs.log.New("renderer", "http")
 		rs.log.Info("Backend rendering via external http server")
 		rs.renderAction = rs.renderViaHttp
 		<-ctx.Done()
@@ -66,6 +68,7 @@ func (rs *RenderingService) Run(ctx context.Context) error {
 	}
 
 	if plugins.Renderer == nil {
+		rs.log = rs.log.New("renderer", "phantomJS")
 		rs.log.Info("Backend rendering via phantomJS")
 		rs.log.Warn("phantomJS is deprecated and will be removed in a future release. " +
 			"You should consider migrating from phantomJS to grafana-image-renderer plugin.")
@@ -74,6 +77,7 @@ func (rs *RenderingService) Run(ctx context.Context) error {
 		return nil
 	}
 
+	rs.log = rs.log.New("renderer", "plugin")
 	rs.pluginInfo = plugins.Renderer
 
 	if err := rs.startPlugin(ctx); err != nil {
@@ -114,6 +118,7 @@ func (rs *RenderingService) Render(ctx context.Context, opts Opts) (*RenderResul
 	rs.inProgressCount += 1
 
 	if rs.renderAction != nil {
+		rs.log.Info("Rendering", "path", opts.Path)
 		return rs.renderAction(ctx, opts)
 	}
 	return nil, fmt.Errorf("No renderer found")