Set variable global

roles/docker-compose/defaults/main.yml

@@ -1 +0,0 @@
-docker_compose_instance_directory:  "{{ path_docker_compose_instances + docker_compose_project_name + '/' }}"

roles/docker-compose/tasks/main.yml

@@ -1,3 +1,7 @@
+- name: "Set global docker_compose_instance_directory: {{ path_docker_compose_instances }}{{ docker_compose_project_name }}/"
+  set_fact:
+    docker_compose_instance_directory: "{{ path_docker_compose_instances }}{{ docker_compose_project_name }}/"
+
 - name: "remove {{ docker_compose_instance_directory }} and all its contents"
   file:
     path: "{{ docker_compose_instance_directory }}"