yamlgroup: add regex match; exclude puppet4 for arm64 mirrors

Two related changes that need to go together because we test with the
production groups.yaml.

Confusingly, there are arm64 PC1 puppet repos, and it contains a bunch
of things that it turns out are the common java parts only.  The
puppet-agent package is not available, and it doesn't seem like it
will be [1].  I think this means we can not run puppet4 on our arm64
xenial ci hosts.

The problem is the mirrors have been updated to puppet4 -- runs are
now breaking on the arm mirrors because they don't have puppet-agent
packages.  It seems all we can really do at this point is contine to
run them on puppet3.

This is hard (impossible?) to express with a fnmatch in the existing
yamlgroups syntax.  We could do something like list all the mirror
hosts and use anchors etc, but we have to keep that maintained.  Add
an feature to the inventory plugin that if the list entry starts with
a ^ it is considered a full regex and passed to re.match.  This
allows us to write more complex matchers where required -- in this
case the arm64 ci mirror hosts are excluded from the puppet4 group.

Testing is updated.

[1] https://groups.google.com/forum/#!msg/puppet-dev/iBMYJpvhaWM/WTGmJvXxAgAJ

Change-Id: I828e0c524f8d5ca866786978486bc04829464b47

inventory/groups.yaml

@@ -175,7 +175,7 @@ groups:
     - logstash-worker[0-9]*.open*.org
     - logstash[0-9]*.open*.org
     - mirror-update[0-9]*.open*.org
-    - mirror[0-9]*.*.*.open*.org
+    - ^mirror[0-9].*\..*\.(?!linaro|linaro-london|arm64ci).*\.open.*\.org
     - openstackid[0-9]*.openstack.org
     - openstackid-dev[0-9]*.openstack.org
     - paste[0-9]*.open*.org

playbooks/roles/install-ansible/files/inventory_plugins/test-fixtures/results.yaml

@@ -39,6 +39,11 @@ results:
     - puppet
     - puppet4
 
+  mirror01.lon1.linaro-london.openstack.org:
+    - afs-client
+    - mirror
+    - puppet
+
   mirror-update01.openstack.org:
     - afsadmin
     - puppet

playbooks/roles/install-ansible/files/inventory_plugins/test_yamlgroup.py

@@ -37,7 +37,7 @@ class TestInventory(testtools.TestCase):
 
         results_yaml = os.path.join(FIXTURE_DIR, 'results.yaml')
         with open(results_yaml) as f:
-            results = yaml.load(f)
+            results = yaml.load(f, Loader=yaml.FullLoader)
             results = results['results']
 
         # Build the inventory list.  This is a list of Host objects
@@ -65,7 +65,7 @@ class TestInventory(testtools.TestCase):
         # real-life, which gets the groups into the config object
         path = os.path.join(FIXTURE_DIR, 'groups.yaml')
         with open(path) as f:
-            config_groups = yaml.load(f)
+            config_groups = yaml.load(f, Loader=yaml.FullLoader)
             config_groups = config_groups['groups']
         im = InventoryModule()
         im._read_config_data = mock.MagicMock()

playbooks/roles/install-ansible/files/inventory_plugins/yamlgroup.py

@@ -3,6 +3,7 @@
 
 import fnmatch
 import os
+import re
 
 from ansible.parsing.yaml.objects import AnsibleMapping
 from ansible.plugins.inventory import BaseFileInventoryPlugin
@@ -28,7 +29,10 @@ DOCUMENTATION = '''
           - section: inventory_plugin_yaml
             key: yaml_valid_extensions
       groups:
-        description: dict with group name as key and list of fnmatch patterns
+        description: |
+          dict with group name as key. If the list item starts with a
+          ^ it will be considered a regex pattern (i.e. passed to
+          re.match), otherwise it is considered a fnmatch pattern.
         type: dict
         default: {}
 '''
@@ -38,6 +42,7 @@ groups:
   amazing:
     - fullhost.example.com
     - amazing*
+    - ^regex.*pattern
 '''
 
 
@@ -75,8 +80,16 @@ class InventoryModule(BaseFileInventoryPlugin):
                 # failing.
                 if isinstance(candidate, AnsibleMapping):
                     candidate = list(candidate.keys())[0]
+
+                # Starts with ^ means it is already a regex.
+                # Otherwise it's a fnmatch compatible string; use it's
+                # helper to turn that into a regex so we have a common
+                # match below.
+                if not candidate.startswith('^'):
+                    candidate = fnmatch.translate(candidate)
+
                 for existing in self.inventory.hosts.values():
-                    if fnmatch.fnmatch(existing.get_name(), candidate):
+                    if re.match(candidate, existing.get_name()):
                         found_groups.setdefault(group, [])
                         found_groups[group].append(existing)