How to parse variables in Ansible group_vars dictionary?

Question

I have previously been placing all of my variables within the inventory file, such as

dse_dir=/app/dse
dse_bin_dir={{ dse_dir }}/bin
dse_conf_dir={{ dse_dir }}/resources/dse/conf
dse_yaml_loc={{ dse_conf_dir }}/dse.yaml
cass_conf_dir={{ dse_dir }}/resources/cassandra/conf
cass_yaml_loc={{ cass_conf_dir }}/cassandra.yaml
cass_bin_dir={{ dse_dir }}/resources/cassandra/bin

I did not need to use any quotes for these variables in the inventory file and it worked quite well.

Now I am trying to make use of the group_vars functionality, to separate variables per group of hosts. This has a different format, being a dictionary. So now I have:

dse_dir: "/app/dse"
dse_bin_dir: "{{ dse_dir }}/bin"
dse_conf_dir: "{{ dse_dir }}/resources/dse/conf"
dse_yaml_loc: "{{ dse_conf_dir }}/dse.yaml"
cass_conf_dir: "{{ dse_dir }}/resources/cassandra/conf"
cass_yaml_loc: "{{ cass_conf_dir }}/cassandra.yaml"
cass_bin_dir: "{{ dse_dir }}/resources/cassandra/bin"

In order to avoid parsing complains, I need to place quotes around these parameters. But now when I have a playbook such as the following:

---
# Copy CQL files across
- include: subtasks/copy_scripts.yml

- name: Create users
  command: '{{ cass_bin_dir })/cqlsh'

I get the following error. Omitting the single quotes or replacing them with double quotes does not work either.

ERROR: There was an error while parsing the task 'command {{ cass_bin_dir })/cqlsh'.
Make sure quotes are matched or escaped properly

All of the documentation that I could find only shows hardcoded values in the dictionary, ie without variables including other variables, but I would assume that Ansible would support this.

Any advice on how to parse these properly?

Answer 1

See the “Gotchas” section here for understanding why you needed to add the quotes in your group_vars . (It's the yaml/ansible problematic : {{ combo.)

To address the error in your command , fix the typo: you have a }) instead of }} .