Implement --check support for the libvirt.virt module (ansible-collections#183)

* Implement check mode for the Virt class

* Implement domain define with check mode

* Implement domain undefine with check mode

* Enable check mode

* Add sanity tests for domain

Author: lowjoel

changelogs/fragments/183-check-mode.yml

@@ -0,0 +1,2 @@
+minor_changes:
+ - virt - implement basic check mode functionality (https://github.com/ansible-collections/community.libvirt/issue/98)

plugins/modules/virt.py

@@ -48,6 +48,10 @@
     - community.libvirt.virt.options_command
     - community.libvirt.virt.options_mutate_flags
     - community.libvirt.requirements
+attributes:
+    check_mode:
+        description: Supports check_mode.
+        support: full
 author:
     - Ansible Core Team
     - Michael DeHaan
@@ -395,6 +399,9 @@ def virttype(self):
 
     def autostart(self, vmid, as_flag):
         self.conn = self.__get_conn()
+        if self.module.check_mode:
+            return self.conn.get_autostart(vmid) != as_flag
+
         # Change autostart flag only if needed
         if self.conn.get_autostart(vmid) != as_flag:
             self.conn.set_autostart(vmid, as_flag)
@@ -408,44 +415,60 @@ def freemem(self):
 
     def shutdown(self, vmid):
         """ Make the machine with the given vmid stop running.  Whatever that takes.  """
+        if self.module.check_mode:
+            return 0
         self.__get_conn()
         self.conn.shutdown(vmid)
         return 0
 
     def pause(self, vmid):
         """ Pause the machine with the given vmid.  """
-
+        if self.module.check_mode:
+            return 0
         self.__get_conn()
         return self.conn.suspend(vmid)
 
     def unpause(self, vmid):
         """ Unpause the machine with the given vmid.  """
-
+        if self.module.check_mode:
+            return 0
         self.__get_conn()
         return self.conn.resume(vmid)
 
     def create(self, vmid):
         """ Start the machine via the given vmid """
-
+        if self.module.check_mode:
+            return 0
         self.__get_conn()
         return self.conn.create(vmid)
 
     def start(self, vmid):
         """ Start the machine via the given id/name """
-
+        if self.module.check_mode:
+            return 0
         self.__get_conn()
         return self.conn.create(vmid)
 
     def destroy(self, vmid):
         """ Pull the virtual power from the virtual domain, giving it virtually no time to virtually shut down.  """
+        if self.module.check_mode:
+            return 0
         self.__get_conn()
         return self.conn.destroy(vmid)
 
     def undefine(self, vmid, flag):
         """ Stop a domain, and then wipe it from the face of the earth.  (delete disk/config file) """
-
+        if self.module.check_mode:
+            return {
+                'changed': vmid in self.list_vms(),
+                'command': 0,
+            }
         self.__get_conn()
-        return self.conn.undefine(vmid, flag)
+        res = self.conn.undefine(vmid, flag)
+        return {
+            'changed': res == 0,
+            'command': res,
+        }
 
     def status(self, vmid):
         """
@@ -483,6 +506,8 @@ def define(self, xml):
         """
         Define a guest with the given xml
         """
+        if self.module.check_mode:
+            return 0
         self.__get_conn()
         return self.conn.define_from_xml(xml)
 
@@ -511,11 +536,12 @@ def handle_define(module, v):
     guest = module.params.get('name', None)
     autostart = module.params.get('autostart', None)
     mutate_flags = module.params.get('mutate_flags', [])
+    parser = etree.XMLParser(remove_blank_text=True)
 
     if not xml:
         module.fail_json(msg="define requires 'xml' argument")
     try:
-        incoming_xml = etree.fromstring(xml)
+        incoming_xml = etree.fromstring(xml, parser)
     except etree.XMLSyntaxError:
         # TODO: provide info from parser
         module.fail_json(msg="given XML is invalid")
@@ -557,7 +583,7 @@ def handle_define(module, v):
     try:
         existing_domain = v.get_vm(domain_name)
         existing_xml_raw = existing_domain.XMLDesc(libvirt.VIR_DOMAIN_XML_INACTIVE)
-        existing_xml = etree.fromstring(existing_xml_raw)
+        existing_xml = etree.fromstring(existing_xml_raw, parser)
     except VMNotFound:
         existing_domain = None
         existing_xml_raw = None
@@ -651,9 +677,19 @@ def get_interface_count(_type, source=None):
                         ))
 
     try:
-        domain_xml = etree.tostring(incoming_xml).decode()
+        domain_xml = etree.tostring(incoming_xml, pretty_print=True).decode()
+
+        if module.check_mode:
+            before = etree.tostring(existing_xml, pretty_print=True).decode() if existing_xml else ''
+            res.update({
+                'changed': before != domain_xml,
+                'diff': {
+                    'before': before,
+                    'after': domain_xml
+                },
+            })
+            return res
 
-        # TODO: support check mode
         domain = v.define(domain_xml)
 
         if existing_domain is not None:
@@ -745,6 +781,12 @@ def core(module):
         return VIRT_SUCCESS, res
 
     if command:
+        def exec_virt(*args):
+            res = getattr(v, command)(*args)
+            if not isinstance(res, dict):
+                res = {command: res}
+            return res
+
         if command in VM_COMMANDS:
             if command == 'define':
                 res.update(handle_define(module, v))
@@ -771,24 +813,18 @@ def core(module):
                 elif force is True:
                     flag = 23
                 # Finally, execute with flag
-                res = getattr(v, command)(guest, flag)
-                if not isinstance(res, dict):
-                    res = {command: res}
+                res = exec_virt(guest, flag)
 
             elif command == 'uuid':
                 res = {'uuid': v.get_uuid(guest)}
 
             else:
-                res = getattr(v, command)(guest)
-                if not isinstance(res, dict):
-                    res = {command: res}
+                res = exec_virt(guest)
 
             return VIRT_SUCCESS, res
 
         elif hasattr(v, command):
-            res = getattr(v, command)()
-            if not isinstance(res, dict):
-                res = {command: res}
+            res = exec_virt()
             return VIRT_SUCCESS, res
 
         else:
@@ -810,6 +846,7 @@ def main():
             xml=dict(type='str'),
             mutate_flags=dict(type='list', elements='str', choices=MUTATE_FLAGS, default=['ADD_UUID']),
         ),
+        supports_check_mode=True
     )
 
     if not HAS_VIRT:

tests/integration/targets/virt/aliases

@@ -0,0 +1,6 @@
+shippable/posix/group1
+skip/aix
+skip/freebsd
+skip/osx
+needs/privileged
+destructive

tests/integration/targets/virt/defaults/main.yml

@@ -0,0 +1,4 @@
+---
+emulator_bin: /usr/bin/qemu-system-x86_64
+domain_info:
+  name: test_dom

tests/integration/targets/virt/tasks/define_check_mode.yml

@@ -0,0 +1,102 @@
+---
+- name: "Determine QEMU version"
+  command: "{{ emulator_bin }} --version"
+  register: emulator_version_output
+
+- name: "Set QEMU version"
+  set_fact:
+    emulator_version: "{{ 0 | extract(emulator_version_output.stdout | regex_search('version (\\d+\\.\\d+)', '\\1')) }}"
+
+#
+# Define domain
+#
+- name: "Define {{ domain_info.name }} on check_mode(pre)"
+  community.libvirt.virt:
+    command: define
+    name: "{{ domain_info.name }}"
+    xml: '{{ lookup("template", "test_domain.xml.j2") }}'
+  register: result_pre
+  check_mode: true
+
+- name: "Define {{ domain_info.name }}"
+  community.libvirt.virt:
+    command: define
+    name: "{{ domain_info.name }}"
+    xml: '{{ lookup("template", "test_domain.xml.j2") }}'
+  register: result
+
+- name: "Define {{ domain_info.name }} on check_mode(post)"
+  community.libvirt.virt:
+    command: define
+    name: "{{ domain_info.name }}"
+    xml: '{{ lookup("template", "test_domain.xml.j2") }}'
+  register: result_post
+  check_mode: true
+
+- name: "Ensure the {{ domain_info.name }} has been defined"
+  assert:
+    that:
+      - result_pre is changed
+      - result is changed
+      - result_post is not changed
+      - result.created == domain_info.name
+
+#
+# Start domain
+#
+- name: "Start {{ domain_info.name }} on check_mode(pre)"
+  community.libvirt.virt:
+    state: running
+    name: "{{ domain_info.name }}"
+  register: result_pre
+  check_mode: true
+
+- name: "Start {{ domain_info.name }}"
+  community.libvirt.virt:
+    state: running
+    name: "{{ domain_info.name }}"
+  register: result
+
+- name: "Start {{ domain_info.name }} on check_mode(post}"
+  community.libvirt.virt:
+    state: running
+    name: "{{ domain_info.name }}"
+  register: result_post
+  check_mode: true
+
+- name: "Ensure the {{ domain_info.name }} has started"
+  assert:
+    that:
+      - result_pre is changed
+      - result is changed and result.msg == 0
+      - result_post is not changed
+
+#
+# Undefine domain
+#
+- name: Delete "{{ domain_info.name }} on check_mode(pre)"
+  community.libvirt.virt:
+    command: undefine
+    name: "{{ domain_info.name }}"
+  register: result_pre
+  check_mode: true
+
+- name: Delete "{{ domain_info.name }}"
+  community.libvirt.virt:
+    command: undefine
+    name: "{{ domain_info.name }}"
+  register: result
+
+- name: Delete "{{ domain_info.name }} on check_mode(post)"
+  community.libvirt.virt:
+    command: undefine
+    name: "{{ domain_info.name }}"
+  register: result_post
+  check_mode: true
+
+- name: "Ensure the {{ domain_info.name }} has been deleted"
+  assert:
+    that:
+      - result_pre is changed
+      - result is changed and result.command == 0
+      - result_post is not changed

tests/integration/targets/virt/tasks/main.yml

@@ -0,0 +1,31 @@
+---
+- include_vars: '{{ item }}'
+  with_first_found:
+    - "{{ ansible_distribution }}-{{ ansible_distribution_version}}.yml"
+    - "{{ ansible_distribution }}-{{ ansible_distribution_major_version}}.yml"
+    - "{{ ansible_distribution }}.yml"
+    - "default.yml"
+
+- block:
+    - name: Install libvirt packages
+      package:
+        name: "{{ virt_domain_packages }}"
+
+    - name: Start libvirt service
+      service:
+        name: libvirtd
+        state: started
+
+    - name: Test check mode for domain defines
+      import_tasks: define_check_mode.yml
+
+  always:
+    - name: Stop libvirt
+      service:
+        name: libvirtd
+        state: stopped
+
+    - name: Remove only the libvirt packages
+      package:
+        name: "{{ virt_domain_packages|select('match', '.*libvirt.*')|list }}"
+        state: absent

tests/integration/targets/virt/templates/test_domain.xml.j2

@@ -0,0 +1,51 @@
+<domain type='qemu'>
+  <name>{{ domain_info['name'] }}</name>
+  <uuid>125388f2-6ab4-4343-a166-bad6ffad017e</uuid>
+  <memory unit='KiB'>4000768</memory>
+  <currentMemory unit='KiB'>4000000</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc-i440fx-{{ emulator_version }}'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <features>
+    <acpi/>
+    <apic/>
+    <pae/>
+  </features>
+  <cpu mode='custom' match='exact' check='none'>
+    <model fallback='forbid'>qemu64</model>
+  </cpu>
+  <clock offset='utc'>
+    <timer name='kvmclock' present='no'/>
+  </clock>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>restart</on_crash>
+  <devices>
+    <emulator>{{ emulator_bin }}</emulator>
+    <controller type='usb' index='0' model='piix3-uhci'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
+    </controller>
+    <controller type='pci' index='0' model='pci-root'/>
+    <controller type='pci' index='1' model='pci-bridge'>
+      <model name='pci-bridge'/>
+      <target chassisNr='1'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
+    </controller>
+    <controller type='pci' index='2' model='pci-bridge'>
+      <model name='pci-bridge'/>
+      <target chassisNr='2'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
+    </controller>
+    <controller type='pci' index='3' model='pci-bridge'>
+      <model name='pci-bridge'/>
+      <target chassisNr='3'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
+    </controller>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <audio id='1' type='none'/>
+    <memballoon model='none'/>
+  </devices>
+</domain>

tests/integration/targets/virt/vars/Debian.yml

@@ -0,0 +1,6 @@
+---
+virt_domain_packages:
+  - libvirt-daemon
+  - libvirt-daemon-system
+  - python-libvirt
+  - python-lxml