simplify vm_guest detection code (#49378)

- remove a lot of repetition
  - change lists to tuples since they are faster to assign

changelogs/fragments/vm_guest_facts.yml

@@ -0,0 +1,2 @@
+bugfixes:
+    - simple code collapse, avoid a lot of repetition

lib/ansible/module_utils/facts/virtual/linux.py

@@ -80,87 +80,63 @@ class LinuxVirtual(Virtual):
                 pass
             return virtual_facts
 
+        # assume guest for this block
+        virtual_facts['virtualization_role'] = 'guest'
+
         product_name = get_file_content('/sys/devices/virtual/dmi/id/product_name')
 
-        if product_name in ['KVM', 'Bochs']:
+        if product_name in ('KVM', 'Bochs'):
             virtual_facts['virtualization_type'] = 'kvm'
-            virtual_facts['virtualization_role'] = 'guest'
             return virtual_facts
 
         if product_name == 'RHEV Hypervisor':
             virtual_facts['virtualization_type'] = 'RHEV'
-            virtual_facts['virtualization_role'] = 'guest'
             return virtual_facts
 
-        if product_name in ['VMware Virtual Platform', 'VMware7,1']:
+        if product_name in ('VMware Virtual Platform', 'VMware7,1'):
             virtual_facts['virtualization_type'] = 'VMware'
-            virtual_facts['virtualization_role'] = 'guest'
             return virtual_facts
 
-        if product_name in ['OpenStack Compute', 'OpenStack Nova']:
+        if product_name in ('OpenStack Compute', 'OpenStack Nova'):
             virtual_facts['virtualization_type'] = 'openstack'
-            virtual_facts['virtualization_role'] = 'guest'
             return virtual_facts
 
         bios_vendor = get_file_content('/sys/devices/virtual/dmi/id/bios_vendor')
 
         if bios_vendor == 'Xen':
             virtual_facts['virtualization_type'] = 'xen'
-            virtual_facts['virtualization_role'] = 'guest'
             return virtual_facts
 
         if bios_vendor == 'innotek GmbH':
             virtual_facts['virtualization_type'] = 'virtualbox'
-            virtual_facts['virtualization_role'] = 'guest'
             return virtual_facts
 
-        if bios_vendor in ['Amazon EC2', 'Hetzner']:
+        if bios_vendor in ('Amazon EC2', 'Hetzner'):
             virtual_facts['virtualization_type'] = 'kvm'
-            virtual_facts['virtualization_role'] = 'guest'
             return virtual_facts
 
         sys_vendor = get_file_content('/sys/devices/virtual/dmi/id/sys_vendor')
 
+        KVM_SYS_VENDORS = ('QEMU', 'oVirt', 'Amazon EC2', 'Google', 'Scaleway')
+        if sys_vendor in KVM_SYS_VENDORS:
+            virtual_facts['virtualization_type'] = 'kvm'
+            return virtual_facts
+
         # FIXME: This does also match hyperv
         if sys_vendor == 'Microsoft Corporation':
             virtual_facts['virtualization_type'] = 'VirtualPC'
-            virtual_facts['virtualization_role'] = 'guest'
             return virtual_facts
 
         if sys_vendor == 'Parallels Software International Inc.':
             virtual_facts['virtualization_type'] = 'parallels'
-            virtual_facts['virtualization_role'] = 'guest'
-            return virtual_facts
-
-        if sys_vendor == 'QEMU':
-            virtual_facts['virtualization_type'] = 'kvm'
-            virtual_facts['virtualization_role'] = 'guest'
-            return virtual_facts
-
-        if sys_vendor == 'oVirt':
-            virtual_facts['virtualization_type'] = 'kvm'
-            virtual_facts['virtualization_role'] = 'guest'
             return virtual_facts
 
         if sys_vendor == 'OpenStack Foundation':
             virtual_facts['virtualization_type'] = 'openstack'
-            virtual_facts['virtualization_role'] = 'guest'
             return virtual_facts
 
-        if sys_vendor == 'Amazon EC2':
-            virtual_facts['virtualization_type'] = 'kvm'
-            virtual_facts['virtualization_role'] = 'guest'
-            return virtual_facts
-
-        if sys_vendor == 'Google':
-            virtual_facts['virtualization_type'] = 'kvm'
-            virtual_facts['virtualization_role'] = 'guest'
-            return virtual_facts
-
-        if sys_vendor == 'Scaleway':
-            virtual_facts['virtualization_type'] = 'kvm'
-            virtual_facts['virtualization_role'] = 'guest'
-            return virtual_facts
+        # unassume guest
+        del virtual_facts['virtualization_role']
 
         if os.path.exists('/proc/self/status'):
             for line in get_file_lines('/proc/self/status'):