parser.go

package vipertemplate

import (
	"text/template"

	"github.com/spf13/viper"
	bufferspool "github.com/sv-tools/buffers-pool"
)

type parser struct {
	viper   *viper.Viper
	visited map[string]struct{}
	funcs   template.FuncMap
	data    interface{}
}

func (p *parser) parse(key string) (interface{}, error) {
	if _, ok := p.visited[key]; ok {
		return nil, newError(key, ErrCircularDependency)
	}

	val := p.viper.Get(key)
	if val == nil {
		return nil, nil
	}

	text, ok := val.(string)
	if !ok {
		return val, nil
	}

	tmpl, err := template.New(key).Funcs(p.funcs).Parse(text)
	if err != nil {
		return "", err
	}

	p.visited[key] = struct{}{}

	buf := bufferspool.Get()
	defer bufferspool.Put(buf)

	if err := tmpl.Execute(buf, p.data); err != nil {
		return "", err
	}

	return buf.String(), nil
}

func (p *parser) get(key string) (interface{}, error) {
	return p.parse(key)
}