diff requirements in ansible

Author: sjpb

.gitignore

@@ -5,3 +5,4 @@ venv
 *.pyc
 packer/openhpc2
 .vscode
+requirements.yml.last

ansible/validate.yml

@@ -10,6 +10,33 @@
         name: passwords
         tasks_from: validate.yml
 
+- name: Validate Ansible Galaxy installs are up to date
+  hosts: localhost
+  gather_facts: false
+  become: false
+  tasks:
+      # Can't use e.g. ansible-galaxy {role,collection} list to check installed
+      # vs desired, as git-installed collections do not provide any metadata for
+      # the actual installed version.
+      # So this compares requirements.yml against a .last version produced by a
+      # successful dev/setup-env.sh run.
+    - assert:
+        that: "{{ _requirements_current == _requirements_installed }}"
+        fail_msg: |
+          Ansible Galaxy installs are out of date:
+
+          {% for req in _requirements_installed | difference(_requirements_current) %}
+          {{ req }}
+          {% endfor %}
+          
+          Run dev/setup-env.sh to fix this.
+      vars:
+        # note difference filter requires lists, so need to rearrange yaml from files.
+        _requirements_path: "{{ appliances_repository_root }}/requirements.yml"
+        _requirements_current: "{{ (lookup('file', _requirements_path) | from_yaml).values() | flatten }}"
+        # below produced by dev/setup-env.sh - gives empty list if file is missing:
+        _requirements_installed: "{{ ((lookup('file', _requirements_path + '.last', errors='ignore') or '{}') | from_yaml ).values() | flatten }}"
+
 - name: Ensure control node is in inventory
   hosts: all
   gather_facts: false

dev/setup-env.sh

@@ -39,3 +39,4 @@ ansible --version
 # Install or update ansible dependencies ...
 ansible-galaxy role install -fr requirements.yml -p ansible/roles
 ansible-galaxy collection install -fr requirements.yml -p ansible/collections
+cp requirements.yml requirements.yml.last