Search templates - give entire query as param

[Roxanatest]

I want the entire elasticsearch template query to be given as parameter. The template to be something like

    {
        "lang": "mustache",
        "source": "\{\"query\": {{query_string}}"
      }

And for the query_string to have for example "match_all":{}

However, this does not work. How can it be configured to work?

[glenacota (Guido Lena Cota)]

Hi,
it would be helpful to know what is the exact error you get. But from your snippet, I'd say that you're getting a json_parse_exception, because Mustache is trying to escape the {{query_string}} tag.
If this is the case, you need to avoid automatic escaping by using the triple mustache (see: https://mustache.github.io/mustache.5.html), like in the snippet below:

{
  "lang": "mustache",
  "source": "{\"query\": {{{query_string}}} }"
}

Update:
According to the documentation, this will also work

{
  "lang": "mustache",
  "source": "{\"query\": {{#toJson}}query_string{{/toJson}} }"
}

[Roxanatest]

The issue was a different one - by default, mustache will escape the html characters. So, we just need to unescape them back. With {{#... }}