From 9a30456ee26e617c4954de7ba5e5f8aff9d83d10 Mon Sep 17 00:00:00 2001
From: Jacob Floyd <cognifloyd@gmail.com>
Date: Fri, 26 Jun 2020 03:27:53 -0500
Subject: [PATCH] Use hostnames instead of hostvar_expressions

---
 plugins/inventory/azure_rm.py | 60 ++++++++++++++++++++++++++---------
 1 file changed, 45 insertions(+), 15 deletions(-)

diff --git a/plugins/inventory/azure_rm.py b/plugins/inventory/azure_rm.py
index 52bb46ada0..9e4050a379 100644
--- a/plugins/inventory/azure_rm.py
+++ b/plugins/inventory/azure_rm.py
@@ -83,6 +83,18 @@
           type: bool
           default: False
           version_added: '2.8'
+        hostnames:
+          description:
+            - A list of Jinja2 expressions in order of precedence to compose inventory_hostname.
+            - Ignores expression if result is an empty string or None value.
+            - By default, inventory_hostname is generated to be globally unique based on the VM host name.
+              See C(plain_host_names) for more details on the default.
+            - An expression of 'default' will force using the default hostname generator if no previous
+              hostname expression resulted in a valid hostname.
+            - Use ``default_inventory_hostname`` to access the default hostname generator's value in
+              any of the Jinja2 expressions.
+          type: list
+          default: [default]
 '''
 
 EXAMPLES = '''
@@ -138,9 +150,11 @@
   # overrides the default ansible_host value with a custom Jinja2 expression, in this case, the first DNS hostname, or
   # if none are found, the first public IP address.
   ansible_host: (public_dns_hostnames + public_ipv4_addresses) | first
-  # overrides the default inventory_hostname value with a custom Jinja2 expression, in this case, a tag called vm_name.
-  # if the tag is not found, use the default_inventory_hostname (see plain_host_names).
-  inventory_hostname: tags.vm_name | default(default_inventory_hostname)
+
+# change how inventory_hostname is generated. Each item is a jinja2 expression similar to hostvar_expressions.
+hostnames:
+  - tags.vm_name
+  - default  # special var that uses the default hashed name
 
 # places hosts in dynamically-created groups based on a variable value.
 keyed_groups:
@@ -184,7 +198,7 @@
 from ansible_collections.azure.azcollection.plugins.module_utils.azure_rm_common import AzureRMAuth
 from ansible.errors import AnsibleParserError, AnsibleError
 from ansible.module_utils.parsing.convert_bool import boolean
-from ansible.module_utils._text import to_native, to_bytes
+from ansible.module_utils._text import to_native, to_bytes, to_text
 from itertools import chain
 from msrest import ServiceClient, Serializer, Deserializer
 from msrestazure import AzureConfiguration
@@ -329,13 +343,14 @@ def _get_hosts(self):
 
         constructable_config_strict = boolean(self.get_option('fail_on_template_errors'))
         constructable_config_compose = self.get_option('hostvar_expressions')
-        constructable_config_inventory_hostname = constructable_config_compose.pop('inventory_hostname')
         constructable_config_groups = self.get_option('conditional_groups')
         constructable_config_keyed_groups = self.get_option('keyed_groups')
 
+        constructable_hostnames = self.get_option('hostnames')
+
         for h in self._hosts:
             # FUTURE: track hostnames to warn if a hostname is repeated (can happen for legacy and for composed inventory_hostname)
-            inventory_hostname = self._get_hostname(h, compose=constructable_config_inventory_hostname, strict=constructable_config_strict)
+            inventory_hostname = self._get_hostname(h, hostnames=constructable_hostnames, strict=constructable_config_strict)
             if self._filter_host(inventory_hostname, h.hostvars):
                 continue
             self.inventory.add_host(inventory_hostname)
@@ -368,15 +383,30 @@ def _filter_host(self, inventory_hostname, hostvars):
 
         return False
 
-    def _get_hostname(self, host, compose=None, strict=False):
-        if not compose:
-            return host.default_inventory_hostname
-        try:
-            return self._compose(compose, host.hostvars)
-        except Exception as e:
-            if strict:
-                raise AnsibleParserError("Error generating inventory_hostname with '{0}' (hostvar_expressions.inventory_hostname) for host {1}: {2}".format(compose, host.default_inventory_hostname, to_native(e))
-            return host.default_inventory_hostname
+    def _get_hostname(self, host, hostnames=None, strict=False):
+        hostname = None
+        errors = []
+
+        for preference in hostnames:
+            if preference == 'default':
+                return host.default_inventory_hostname
+            try:
+                hostname = self._compose(preference, host.hostvars)
+            except Exception as e:  # pylint: disable=broad-except
+                if strict:
+                    raise AnsibleError("Could not compose %s as hostnames - %s" % (preference, to_native(e)))
+                else:
+                    errors.append(
+                        (preference, str(e))
+                    )
+            if hostname:
+                return to_text(hostname)
+
+        raise AnsibleError(
+            'Could not template any hostname for host, errors for each preference: %s' % (
+                ', '.join(['%s: %s' % (pref, err) for pref, err in errors])
+            )
+        )
 
     def _process_queue_serial(self):
         try: