Add a required version plugin

README.md

@@ -15,7 +15,7 @@ If you struggle with following the instructions for setting up the requirements
 1. [VirtualBox](https://www.virtualbox.org/)
 2. [Vagrant](http://www.vagrantup.com/) (Known to work with 2.0.1 - 2.1.2)
 3. [git](https://git-scm.com/)
-4. [ansible](https://www.ansible.com/community) 2.3+
+4. [ansible](https://www.ansible.com/community) (restricted to versions 2.6.0 - 2.8.7)
 5. [virtualbox-vbguest](https://github.com/dotless-de/vagrant-vbguest) plugin (If targeting CENTOS)
 
 ## Variables

ansible-version.yml

@@ -0,0 +1,5 @@
+---
+  # Minimum version of ansible this playbook works with.
+  islandora_ansible_version_min: 2.6.0
+  # Maximum version of ansible this playbook works with.
+  islandora_ansible_version_max: 2.8.7

callback_plugins/ansible-version.py

@@ -0,0 +1,52 @@
+# -*- encoding:utf-8 -*-
+# Copied from https://adamj.eu/tech/2016/08/19/restricting-the-ansible-version-in-use/
+# and edited to our use-case.
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import sys
+import os
+import os.path
+import yaml
+from distutils.version import StrictVersion
+
+import ansible
+
+try:
+    # Version 2.0+
+    from ansible.plugins.callback import CallbackBase
+except ImportError:
+    CallbackBase = object
+
+
+class CallbackModule(CallbackBase):
+    def __init__(self):
+        self.minimum_version = StrictVersion('2.7.0')
+        self.maximum_version = StrictVersion('2.8.7')
+        self.load_from_main()
+        current_version = StrictVersion(ansible.__version__)
+        # Can't use `on_X` because this isn't forwards compatible with Ansible 2.0+
+        if current_version < self.minimum_version or current_version > self.maximum_version:
+            CallbackModule.print_red_bold(
+                "Islandora-Playbook restriction: only an Ansible version between {minversion} and {maxversion} is supported."
+                .format(minversion=self.minimum_version, maxversion=self.maximum_version)
+            )
+            sys.exit(1)
+
+    @staticmethod
+    def print_red_bold(text):
+        print('\x1b[31;1m' + text + '\x1b[0m')
+
+    def load_from_main(self):
+        current_dir = os.getcwd()
+        version_file = os.path.join(current_dir, 'ansible-version.yml')
+        if os.path.exists(version_file):
+            with open(version_file, 'r') as fp:
+                versions = yaml.load(fp, Loader=yaml.SafeLoader)
+            try:
+                self.minimum_version = StrictVersion(versions['islandora_ansible_version_min'])
+            except KeyError:
+                pass
+            try:
+                self.maximum_version = StrictVersion(versions['islandora_ansible_version_max'])
+            except KeyError:
+                pass