Merge pull request #12198 from grafana/11868_missing_phantom

enhance error message if phantomjs executable is not found

pkg/api/render.go

@@ -3,7 +3,9 @@ package api
 import (
 	"fmt"
 	"net/http"
+	"runtime"
 	"strconv"
+	"strings"
 	"time"
 
 	m "github.com/grafana/grafana/pkg/models"
@@ -55,6 +57,15 @@ func (hs *HTTPServer) RenderToPng(c *m.ReqContext) {
 		return
 	}
 
+	if err != nil && err == rendering.ErrPhantomJSNotInstalled {
+		if strings.HasPrefix(runtime.GOARCH, "arm") {
+			c.Handle(500, "Rendering failed - PhantomJS isn't included in arm build per default", err)
+		} else {
+			c.Handle(500, "Rendering failed - PhantomJS isn't installed correctly", err)
+		}
+		return
+	}
+
 	if err != nil {
 		c.Handle(500, "Rendering failed.", err)
 		return

pkg/services/rendering/interface.go

@@ -10,6 +10,7 @@ import (
 
 var ErrTimeout = errors.New("Timeout error. You can set timeout in seconds with &timeout url parameter")
 var ErrNoRenderer = errors.New("No renderer plugin found nor is an external render server configured")
+var ErrPhantomJSNotInstalled = errors.New("PhantomJS executable not found")
 
 type Opts struct {
 	Width    int

pkg/services/rendering/phantomjs.go

@@ -24,6 +24,11 @@ func (rs *RenderingService) renderViaPhantomJS(ctx context.Context, opts Opts) (
 
 	url := rs.getURL(opts.Path)
 	binPath, _ := filepath.Abs(filepath.Join(rs.Cfg.PhantomDir, executable))
+	if _, err := os.Stat(binPath); os.IsNotExist(err) {
+		rs.log.Error("executable not found", "executable", binPath)
+		return nil, ErrPhantomJSNotInstalled
+	}
+
 	scriptPath, _ := filepath.Abs(filepath.Join(rs.Cfg.PhantomDir, "render.js"))
 	pngPath := rs.getFilePathForNewImage()