Run the pre.requirements file before the base requirements file.

playbooks/roles/edxapp/tasks/main.yml

@@ -82,6 +82,14 @@
   - install
 
 
+# Install the python post requirements into {{ venv_dir }}
+- name : install python post-requirements
+  pip: requirements="{{pre_requirements_file}}" virtualenv="{{venv_dir}}" state=present
+  tags:
+  - lms
+  - cms
+  - install
+
 # Install the python modules into {{ venv_dir }}
 - name : install base python packages using the shell
   # Need to use shell rather than pip so that we can maintain the context of our current working directory; some 

playbooks/roles/edxapp/vars/main.yml

@@ -27,6 +27,7 @@ lms_xml_env_config: {}
 lms_source_repo: git@github.com:edx/edx-platform.git
 lms_version: 'HEAD'
 local_requirements_file:  "{{ platform_code_dir }}/requirements/edx/local.txt"
+pre_requirements_file:   "{{ platform_code_dir }}/requirements/edx/pre.txt"
 post_requirements_file:   "{{ platform_code_dir }}/requirements/edx/post.txt"
 base_requirements_file:   "{{ platform_code_dir }}/requirements/edx/base.txt"
 github_requirements_file: "{{ platform_code_dir }}/requirements/edx/github.txt"