Enable image rendering to use browser time offset

pkg/api/render.go

@@ -14,11 +14,12 @@ func RenderToPng(c *middleware.Context) {
 	queryParams := fmt.Sprintf("?%s", c.Req.URL.RawQuery)
 
 	renderOpts := &renderer.RenderOpts{
-		Path:    c.Params("*") + queryParams,
-		Width:   queryReader.Get("width", "800"),
-		Height:  queryReader.Get("height", "400"),
-		OrgId:   c.OrgId,
-		Timeout: queryReader.Get("timeout", "30"),
+		Path:       c.Params("*") + queryParams,
+		Width:      queryReader.Get("width", "800"),
+		Height:     queryReader.Get("height", "400"),
+		OrgId:      c.OrgId,
+		Timeout:    queryReader.Get("timeout", "30"),
+		TimeOffset: queryReader.Get("timeOffset", ""),
 	}
 
 	pngPath, err := renderer.RenderToPng(renderOpts)

pkg/components/renderer/renderer.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"runtime"
 	"time"
 
@@ -15,18 +16,44 @@ import (
 	"github.com/grafana/grafana/pkg/middleware"
 	"github.com/grafana/grafana/pkg/setting"
 	"github.com/grafana/grafana/pkg/util"
+	"strings"
 )
 
 type RenderOpts struct {
-	Path    string
-	Width   string
-	Height  string
-	Timeout string
-	OrgId   int64
+	Path       string
+	Width      string
+	Height     string
+	Timeout    string
+	OrgId      int64
+	TimeOffset string
 }
 
 var rendererLog log.Logger = log.New("png-renderer")
 
+func isoTimeOffsetToPosixTz(isoOffset string) string {
+	re := regexp.MustCompile(`^([+-])([0-1][0-9]|2[0-4])([0-5][0-9])$`)
+	results := re.FindStringSubmatch(isoOffset)
+	if results == nil {
+		return ""
+	}
+	sign := "+"
+	if results[1] == "+" {
+		sign = "-"  // "+" is west and "-" is east in POSIX TZ
+	}
+	return fmt.Sprintf("SOMEWHERE%s%s:%s", sign, results[2], results[3])
+}
+
+func appendEnviron(baseEnviron []string, name string, value string) []string {
+	results := make([]string, 0)
+	prefix := fmt.Sprintf("%s=", name)
+	for _, v := range baseEnviron {
+		if !strings.HasPrefix(v, prefix) {
+			results = append(results, v)
+		}
+	}
+	return append(results, fmt.Sprintf("%s=%s", name, value))
+}
+
 func RenderToPng(params *RenderOpts) (string, error) {
 	rendererLog.Info("Rendering", "path", params.Path)
 
@@ -73,6 +100,12 @@ func RenderToPng(params *RenderOpts) (string, error) {
 		return "", err
 	}
 
+	tz := isoTimeOffsetToPosixTz(params.TimeOffset)
+	if tz != "" {
+		baseEnviron := os.Environ()
+		cmd.Env = appendEnviron(baseEnviron, "TZ", tz)
+	}
+
 	err = cmd.Start()
 	if err != nil {
 		return "", err

public/app/features/dashboard/partials/shareModal.html

@@ -69,6 +69,15 @@
 	</div>
 </script>
 
+<script type="text/ng-template" id="renderImageOptions.html">
+	<div class="gf-form-group">
+		<gf-form-switch class="gf-form"
+			label="Use browser time offset in image" label-class="width-18" switch-class="max-width-6"
+			checked="options.browserTimeOffset" on-change="buildUrl()">
+		</gf-form-switch>
+	</div>
+</script>
+
 <script type="text/ng-template" id="shareLink.html">
 	<div class="share-modal-header">
 		<div class="share-modal-big-icon">
@@ -91,6 +100,7 @@
 					</div>
 				</div>
 			</div>
+			<div ng-include src="'renderImageOptions.html'"></div>
 			<div class="gf-form" ng-show="modeSharePanel">
 				<a href="{{imageUrl}}" target="_blank"><i class="fa fa-camera"></i> Direct link rendered image</a>
 			</div>

public/app/features/dashboard/shareModalCtrl.js

@@ -10,7 +10,7 @@ function (angular, _, require, config) {
 
   module.controller('ShareModalCtrl', function($scope, $rootScope, $location, $timeout, timeSrv, templateSrv, linkSrv) {
 
-    $scope.options = { forCurrent: true, includeTemplateVars: true, theme: 'current' };
+    $scope.options = { forCurrent: true, includeTemplateVars: true, browserTimeOffset: false, theme: 'current' };
     $scope.editor = { index: $scope.tabIndex || 0};
 
     $scope.init = function() {
@@ -82,6 +82,13 @@ function (angular, _, require, config) {
       $scope.imageUrl = soloUrl.replace(config.appSubUrl + '/dashboard-solo/', config.appSubUrl + '/render/dashboard-solo/');
       $scope.imageUrl += '&width=1000';
       $scope.imageUrl += '&height=500';
+      if ($scope.options.browserTimeOffset) {
+        var offsetMinutes = new Date().getTimezoneOffset(); // Negative if ahead of UTC
+        var sign = offsetMinutes < 0 ? '+' : '-';
+        var hours = ('0' + Math.abs(offsetMinutes) / 60).slice(-2);
+        var minutes = ('0' + Math.abs(offsetMinutes) % 60).slice(-2);
+        $scope.imageUrl += '&timeOffset=' + encodeURIComponent(sign + hours + minutes);
+      }
     };
 
   });