Remove quotes from Ansible variable output

Question

I'm using this task to add a line to a file:

lineinfile: "dest={{ ansible_env.HOME }}/{{ deploy_dir }}/config/deploy/{{ stage_name }}.rb
              insertbefore='# role-based syntax'
              line='server "'{{ ip_addr }}'", user: "'{{ user_name }}'", roles: %w{'{{ role }}'}'"

Which adds this line:

server '172.16.8.11', user: 'vagrant', roles: %w{'api'}

But I don't want the quotes around api. Instead I want this output:

server '172.16.8.11', user: 'vagrant', roles: %w{api}

Solution

Actually the quotes do not come from the variable, but are right there in your string:

%w{'{{ role }}'}

Now the solution is little bit tricky though. Because you can not simply remove the quotes like that:

%w{{{ role }}}

This would result into a parse error, since {{ starts an expression...

The solution is to write the outer parentheses, which are meant to be in the string, as an expression themselves.

So to output { you would instead write {{'{'}} and instead of } you would write {{'}'}}. Does that make sense? You're instructing the template engine (Jinja2) to output the parentheses to avoid the parsing error:

%w{{'{'}}{{ role }}{{'}'}}

But since role is an expression already, you just also can group it together into one single expression:

%w{{ '{'+role+'}' }}

Your whole task would then read like this:

- lineinfile:
    dest: "{{ ansible_env.HOME }}/{{ deploy_dir }}/config/deploy/{{ stage_name }}.rb"
    insertbefore: "# role-based syntax"
    line: "server '{{ ip_addr }}', user: '{{ user_name }}', roles: %w{{ '{'+role+'}' }}"

^{This also is converted into proper YAML syntax because this quoted k=v format is just really hard to read. :)}