Allow arbitrary data to be passed to templates

server/server.go

@@ -107,6 +107,9 @@ type WebConfig struct {
 
 	// Defaults to "coreos"
 	Theme string
+
+	// Map of extra values passed into the templates
+	Extra map[string]string
 }
 
 func value(val, defaultValue time.Duration) time.Duration {
@@ -181,6 +184,7 @@ func newServer(ctx context.Context, c Config, rotationStrategy rotationStrategy)
 		issuerURL: c.Issuer,
 		issuer:    c.Web.Issuer,
 		theme:     c.Web.Theme,
+		extra:     c.Web.Extra,
 	}
 
 	static, theme, tmpls, err := loadWebConfig(web)

server/templates.go

@@ -42,6 +42,7 @@ type webConfig struct {
 	issuer    string
 	theme     string
 	issuerURL string
+	extra     map[string]string
 }
 
 func join(base, path string) string {
@@ -140,6 +141,7 @@ func loadTemplates(c webConfig, templatesDir string) (*templates, error) {
 		"logo":   func() string { return c.logoURL },
 		"url":    func(s string) string { return join(c.issuerURL, s) },
 		"lower":  strings.ToLower,
+		"extra":  func(k string) string { return c.extra[k] },
 	}
 
 	tmpls, err := template.New("").Funcs(funcs).ParseFiles(filenames...)