template/template.go
func NewTemplate(i *NewTemplateInput) (*Template, error) {
	if i == nil {
		i = &NewTemplateInput{}
	}

	// Validate that we are either given the path or the explicit contents
	if i.Source != "" && i.Contents != "" {
		return nil, ErrTemplateContentsAndSource
	} else if i.Source == "" && i.Contents == "" {
		return nil, ErrTemplateMissingContentsAndSource
	}

	var t Template
	t.source = i.Source
	t.contents = i.Contents
	t.leftDelim = i.LeftDelim
	t.rightDelim = i.RightDelim
	t.errMissingKey = i.ErrMissingKey

	if i.Source != "" {
		contents, err := ioutil.ReadFile(i.Source)
		if err != nil {
			return nil, errors.Wrap(err, "failed to read template")
		}
		t.contents = string(contents)
	}

	// Compute the MD5, encode as hex
	hash := md5.Sum([]byte(t.contents))
	t.hexMD5 = hex.EncodeToString(hash[:])

	return &t, nil
}
func NewTemplate(i *NewTemplateInput) (*Template, error) {
	if i == nil {
		i = &NewTemplateInput{}
	}

	// Validate that we are either given the path or the explicit contents
	if i.Source != "" && i.Contents != "" {
		return nil, ErrTemplateContentsAndSource
	} else if i.Source == "" && i.Contents == "" {
		return nil, ErrTemplateMissingContentsAndSource
	}

	var t Template
	t.source = i.Source
	t.contents = i.Contents
	t.leftDelim = i.LeftDelim
	t.rightDelim = i.RightDelim
	t.errMissingKey = i.ErrMissingKey

	if i.Source != "" {
		contents, err := ioutil.ReadFile(i.Source)
		if err != nil {
			return nil, errors.Wrap(err, "failed to read template")
		}
		t.contents = string(contents)
	}

	// Compute the MD5, encode as hex
	hash := md5.Sum([]byte(t.contents))
	t.hexMD5 = hex.EncodeToString(hash[:])

	return &t, nil
}
// NewTemplate creates and parses a new Consul Template template at the given
// path. If the template does not exist, an error is returned. During
// initialization, the template is read and is parsed for dependencies. Any
// errors that occur are returned.