write-inventory: add per-host variables

This allows us to write out host-specific variables into the inventory
from external jobs.

Change-Id: I0c3d08f6446174cb38d5eebaeae1db9dceb956b2

roles/write-inventory/README.rst

@@ -39,3 +39,21 @@ with the inventory for the job.
 
    This will map hostvars[hostname]['nodepool']['public_ipv4'] to
    hostvars[hostname]['public_v4'].
+
+.. zuul:rolevar:: write_inventory_per_host_hostvars
+   :type: dict
+
+   An additional dictionary added on a per-host basis.  The keys of
+   this dictionary should be hostnames, if the host name matches, the
+   value (also a dictionary) is merged into the hostvars for that
+   host.  For example below, ``hosta.com`` will have ``foo`` with
+   value ``bar``, while ``hostb.com`` will have ``foo`` with value
+   ``baz``.
+
+   .. code-block:: yaml
+
+      write_inventory_per_host_hostvars:
+         hosta.com:
+           foo: bar
+         hostb.com:
+           foo: baz

roles/write-inventory/library/test_write_inventory.py

@@ -73,7 +73,7 @@ class TestWriteInventory(testtools.TestCase):
         '''Test passing all variables'''
         dest = self.useFixture(fixtures.TempDir()).path
         dest = os.path.join(dest, 'out.yaml')
-        run(dest, INPUT, GROUPS_INPUT, None, None, None)
+        run(dest, INPUT, GROUPS_INPUT, None, None, None, None)
 
         self.assertOutput(dest, {
             'all': {
@@ -106,7 +106,7 @@ class TestWriteInventory(testtools.TestCase):
         '''Test incuding vars'''
         dest = self.useFixture(fixtures.TempDir()).path
         dest = os.path.join(dest, 'out.yaml')
-        run(dest, INPUT, GROUPS_INPUT, ['ansible_host'], None, None)
+        run(dest, INPUT, GROUPS_INPUT, ['ansible_host'], None, None, None)
 
         self.assertOutput(dest, {
             'all': {
@@ -133,7 +133,7 @@ class TestWriteInventory(testtools.TestCase):
         '''Test passing all variables'''
         dest = self.useFixture(fixtures.TempDir()).path
         dest = os.path.join(dest, 'out.yaml')
-        run(dest, INPUT, GROUPS_INPUT, None, ['ansible_user'], None)
+        run(dest, INPUT, GROUPS_INPUT, None, ['ansible_user'], None, None)
 
         self.assertOutput(dest, {
             'all': {
@@ -167,7 +167,8 @@ class TestWriteInventory(testtools.TestCase):
         run(dest, INPUT, GROUPS_INPUT, None, None,
             {'public_v4': 'nodepool.public_ipv4',
              'public_v6': 'nodepool.public_ipv6',
-        })
+            },
+            None)
 
         self.assertOutput(dest, {
             'all': {
@@ -197,3 +198,56 @@ class TestWriteInventory(testtools.TestCase):
                 }
             }
         })
+
+    def test_per_host(self):
+        '''Test passing additional variables per host'''
+        dest = self.useFixture(fixtures.TempDir()).path
+        dest = os.path.join(dest, 'out.yaml')
+        run(dest, INPUT, GROUPS_INPUT, None, None,
+            {
+                'public_v4': 'nodepool.public_ipv4',
+                'public_v6': 'nodepool.public_ipv6',
+            },
+            {
+                'bionic': {
+                    'a': 'extra',
+                    'b': 'variable',
+                },
+                'xenial': {
+                    'c': 'extra',
+                    'd': 'variable',
+                },
+            })
+
+        self.assertOutput(dest, {
+            'all': {
+                'children': {
+                    'puppet': {
+                        'hosts': {
+                            'bionic': None,
+                            'xenial': None,
+                        },
+                    },
+                },
+                'hosts': {
+                    'bionic': {
+                        "ansible_connection": "ssh",
+                        "ansible_user": "zuul",
+                        "ansible_host": "104.130.217.77",
+                        "ansible_port": 22,
+                        "public_v4": "104.130.217.77",
+                        "a": "extra",
+                        "b": "variable"
+                    },
+                    'xenial': {
+                        "ansible_connection": "ssh",
+                        "ansible_user": "zuul",
+                        "ansible_host": "149.202.170.85",
+                        "ansible_port": 22,
+                        "public_v6": "2001:41d0:302:1000::17:a32b",
+                        "c": "extra",
+                        "d": "variable"
+                    }
+                }
+            }
+        })

roles/write-inventory/library/write_inventory.py

@@ -28,7 +28,7 @@ VARS = [
 ]
 
 
-def run(dest, hostvars, groups, include, exclude, additional):
+def run(dest, hostvars, groups, include, exclude, additional, per_host):
     children = {}
     for group, hostnames in groups.items():
         if group == 'all' or group == 'ungrouped':
@@ -67,6 +67,9 @@ def run(dest, hostvars, groups, include, exclude, additional):
                         break
                 else:
                     d[new_var_name] = old_var
+        if per_host:
+            if host in per_host:
+                d.update(per_host[host])
 
     with open(dest, 'w') as f:
         f.write(json.dumps(out))
@@ -81,6 +84,7 @@ def ansible_main():
             include_hostvars=dict(type='list'),
             exclude_hostvars=dict(type='list'),
             additional_hostvars=dict(type='raw'),
+            per_host_hostvars=dict(type='raw'),
         )
     )
 
@@ -92,8 +96,9 @@ def ansible_main():
     include = p.get('include_hostvars')
     exclude = p.get('exclude_hostvars')
     additional = p.get('additional_hostvars', {})
+    per_host = p.get('per_host_hostvars', {})
 
-    run(dest, hostvars, groups, include, exclude, additional)
+    run(dest, hostvars, groups, include, exclude, additional, per_host)
 
     module.exit_json(changed=True)
 

roles/write-inventory/tasks/main.yaml

@@ -6,3 +6,4 @@
     include_hostvars: "{{ write_inventory_include_hostvars | default(omit) }}"
     exclude_hostvars: "{{ write_inventory_exclude_hostvars | default(omit) }}"
     additional_hostvars: "{{ write_inventory_additional_hostvars | default(omit) }}"
+    per_host_hostvars: "{{ write_inventory_per_host_hostvars | default(omit) }}"