Added basic template rendering.

util/cache.go

@@ -0,0 +1,55 @@
+package util
+
+import (
+	"github.com/emvi/logbuch"
+	"html/template"
+	"sync"
+)
+
+// TemplateCache caches templates.
+type TemplateCache struct {
+	templates map[string]*template.Template
+	mutex     sync.RWMutex
+}
+
+// NewTemplateCache creates a new template cache.
+func NewTemplateCache() *TemplateCache {
+	return &TemplateCache{templates: make(map[string]*template.Template)}
+}
+
+// ParseFiles parses the given template files and stores them as one template called name.
+func (tplcache *TemplateCache) ParseFiles(name string, files ...string) (*template.Template, error) {
+	if tplcache.templates[name] != nil {
+		tplcache.mutex.RLock()
+		defer tplcache.mutex.RUnlock()
+		return tplcache.templates[name], nil
+	}
+
+	tplcache.mutex.Lock()
+	defer tplcache.mutex.Unlock()
+	logbuch.Debug("Caching template", logbuch.Fields{"name": name})
+	tpl, err := template.ParseFiles(files...)
+
+	if err != nil {
+		return nil, err
+	}
+
+	tplcache.templates[name] = tpl
+	return tpl, nil
+}
+
+// GetTemplate returns a cached template by name or nil if not found.
+func (tplcache *TemplateCache) GetTemplate(name string) *template.Template {
+	if tplcache.templates[name] != nil {
+		tplcache.mutex.RLock()
+		defer tplcache.mutex.RUnlock()
+		return tplcache.templates[name]
+	}
+
+	return nil
+}
+
+// Clear clears the template cache.
+func (tplcache *TemplateCache) Clear() {
+	tplcache.templates = make(map[string]*template.Template)
+}