How to render a "template of templates", without escaping each action

Does anyone know how to render a "template of templates" with text/template, where only specific actions (ie: things wrapped in {{...}}) will be rendered, and the rest will be treated as literals?

For example, given the following template:

I want to render {{.Foo}}.

but I don't want to render anything on this line, like {{.Bar}} or this template: [{{ .Status | toUpper }}{{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}

Render {{.Foo}} again.

I want to render the following output:

I want to render foo.

but I don't want to render anything on this line, like {{.Bar}} or this template: [{{ .Status | toUpper }}{{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}

Render foo again.

While I can escape each portion of my desired literal with {{ "{{" }}, it feels a bit tedious.

I imagine that I should be able to do something like I want to render {{template "outer" .Foo}}. and call something like tmpl.ExecuteTemplate(&buff, "outer", data) to only render my specified "outer" actions.

I also wonder if rendering a "template of templates" is a code smell, and I should replace my "outer" template with a string/replace if possible, like I want to render <<.Foo>>.

You can change the delimiters for the first level of template:

tmpl := template.New("name").Delims("<<",">>").Parse(...)

Then, write the template as:

I want to render <<.Foo>>.

but I don't want to render anything on this line, like {{.Bar}}...

{{define "outer"}}
I want to render {{.}}
{{end}}

{{$ignored := `but I don't want to render anything on this line, like {{.Bar}} or this template: [{{ .Status | toUpper }}{{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}`}}

{{template "outer" .Foo}}

{{$ignored}}

Render {{template "outer" .Foo}} again.

Option 1: Use different delimiters for the inner and outer templates.

t := template.Must(template.New("").Delims("<<", ">>").Parse(`
I want to render <<.Foo>>.

but I don't want to render anything on this line, like {{.Bar}} or this template: [{{ .Status | toUpper }}{{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}

Render <<.Foo>> again.`))

This program:

var buf bytes.Buffer
if err := t.Execute(&buf, map[string]any{"Foo": "foo"}); err != nil {
    log.Fatal(err)
}
fmt.Println(buf.String())

prints:

I want to render foo.

but I don't want to render anything on this line, like {{.Bar}} or this template: [{{ .Status | toUpper }}{{ if eq .Status "firing" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}

Render foo again.

https://go.dev/play/p/ueqstNKVUWQ

Option 2: Emit the entire line as a string literal. This requires the " in the line to be quoted, but that's not as bad as quoting all of the {{.

I want to render {{.Foo}}.

{{"but I don't want to render anything on this line, like {{.Bar}} or this template: [{{ .Status | toUpper }}{{ if eq .Status \"firing\" }}:{{ .Alerts.Firing | len }}{{ end }}] {{ .CommonLabels.alertname }} for {{ .CommonLabels.job }}"}}

Render {{.Foo}} again.

https://go.dev/play/p/ueqstNKVUWQ