Ansible parses strings as lists if the format is compatible, how to escape?

Question

Using ansible, I need to put a list of hosts in line in a file like so:

[\"127.0.0.1\", \"127.0.0.2\", \"127.0.0.3\"]

But whenever I achieve th

Answer 1

There are some filters that prevent Ansible template engine from doing string evaluation.
This list of filters is stored in STRING_TYPE_FILTERS setting.
In Ansible 2.1 it contains: string, to_json, to_nice_json, to_yaml, ppretty, json.

So, you can do this:

- lineinfile: line="{{ myhosts | to_json }}" dest=output.txt

This will add ["127.0.0.1", "127.0.0.2", "127.0.0.3"] line to the file.

And don't believe debug's output when dealing with exact string formatting.
Always use copy: content="{{ string_output_to_test | string }}" dest=test.txt and check file contents to be sure.

debug: var=myvar will always template with evaluation, so your string will always be printed as a list.
debug: msg="{{ myvar | string }}" will print myvar as JSON encoded string.