Add a Singleton metaclass, use it with Display (#48935)

* Add a Singleton class, use it with Display

* update six import

* Move remaining failes to display singleton

* Fix rebase issues

* Singleton improvements

* Add code-smell for 'from __main__ import display'. ci_complete

* s/self/cls/g

* Add docs for no-main-display

* Address linting issues

* Add changelog fragment. ci_complete

* Implement reentrant lock for class instantiation in Singleton

* Add Display singleton porting guide

lib/ansible/plugins/lookup/__init__.py

@@ -23,12 +23,9 @@ from abc import abstractmethod
 
 from ansible.errors import AnsibleFileNotFound
 from ansible.plugins import AnsiblePlugin
+from ansible.utils.display import Display
 
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+display = Display()
 
 __all__ = ['LookupBase']
 

lib/ansible/plugins/lookup/aws_ssm.py

@@ -103,12 +103,7 @@ from ansible.module_utils._text import to_native
 from ansible.module_utils.ec2 import HAS_BOTO3, boto3_tag_list_to_ansible_dict
 from ansible.errors import AnsibleError
 from ansible.plugins.lookup import LookupBase
-
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+from ansible.utils.display import Display
 
 try:
     from botocore.exceptions import ClientError
@@ -117,6 +112,8 @@ try:
 except ImportError:
     pass  # will be captured by imported HAS_BOTO3
 
+display = Display()
+
 
 def _boto3_conn(region, credentials):
     if 'boto_profile' in credentials:

lib/ansible/plugins/lookup/conjur_variable.py

@@ -64,13 +64,9 @@ from ansible.module_utils.six.moves.urllib.parse import quote_plus
 import yaml
 
 from ansible.module_utils.urls import open_url
+from ansible.utils.display import Display
 
-
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+display = Display()
 
 
 # Load configuration and return as dictionary if file is present on file system

lib/ansible/plugins/lookup/cpm_metering.py

@@ -111,12 +111,9 @@ from ansible.plugins.lookup import LookupBase
 from ansible.module_utils._text import to_text, to_bytes, to_native
 from ansible.module_utils.six.moves.urllib.error import HTTPError, URLError
 from ansible.module_utils.urls import open_url, ConnectionError, SSLValidationError
+from ansible.utils.display import Display
 
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+display = Display()
 
 
 class LookupModule(LookupBase):

lib/ansible/plugins/lookup/cyberarkpassword.py

@@ -73,12 +73,9 @@ from ansible.errors import AnsibleError
 from ansible.plugins.lookup import LookupBase
 from ansible.parsing.splitter import parse_kv
 from ansible.module_utils._text import to_text
+from ansible.utils.display import Display
 
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+display = Display()
 
 CLIPASSWORDSDK_CMD = os.getenv('AIM_CLIPASSWORDSDK_CMD', '/opt/CARKaim/sdk/clipasswordsdk')
 

lib/ansible/plugins/lookup/file.py

@@ -50,12 +50,9 @@ RETURN = """
 from ansible.errors import AnsibleError, AnsibleParserError
 from ansible.plugins.lookup import LookupBase
 from ansible.module_utils._text import to_text
+from ansible.utils.display import Display
 
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+display = Display()
 
 
 class LookupModule(LookupBase):

lib/ansible/plugins/lookup/filetree.py

@@ -99,12 +99,9 @@ except ImportError:
 
 from ansible.plugins.lookup import LookupBase
 from ansible.module_utils._text import to_native, to_text
+from ansible.utils.display import Display
 
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+display = Display()
 
 
 # If selinux fails to find a default, return an array of None

lib/ansible/plugins/lookup/grafana_dashboard.py

@@ -67,12 +67,9 @@ from ansible.plugins.lookup import LookupBase
 from ansible.module_utils.urls import open_url
 from ansible.module_utils._text import to_bytes, to_native
 from ansible.module_utils.six.moves.urllib.error import HTTPError
+from ansible.utils.display import Display
 
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+display = Display()
 
 
 ANSIBLE_GRAFANA_URL = 'http://127.0.0.1:3000'

lib/ansible/plugins/lookup/keyring.py

@@ -36,21 +36,17 @@ RETURN = """
 HAS_KEYRING = True
 
 from ansible.errors import AnsibleError
+from ansible.utils.display import Display
 
 try:
     import keyring
 except ImportError:
     HAS_KEYRING = False
 
-
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
-
 from ansible.plugins.lookup import LookupBase
 
+display = Display()
+
 
 class LookupModule(LookupBase):
 

lib/ansible/plugins/lookup/rabbitmq.py

@@ -97,16 +97,12 @@ RETURN = """
 
 """
 
+import json
+
 from ansible.errors import AnsibleError, AnsibleParserError
 from ansible.plugins.lookup import LookupBase
 from ansible.module_utils._text import to_native, to_text
-import json
-
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+from ansible.utils.display import Display
 
 try:
     import pika
@@ -115,6 +111,8 @@ try:
 except ImportError:
     HAS_PIKA = False
 
+display = Display()
+
 
 class LookupModule(LookupBase):
 

lib/ansible/plugins/lookup/template.py

@@ -38,12 +38,9 @@ from ansible.errors import AnsibleError
 from ansible.plugins.lookup import LookupBase
 from ansible.module_utils._text import to_bytes, to_text
 from ansible.template import generate_ansible_template_vars
+from ansible.utils.display import Display
 
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+display = Display()
 
 
 class LookupModule(LookupBase):

lib/ansible/plugins/lookup/url.py

@@ -60,12 +60,9 @@ from ansible.module_utils.six.moves.urllib.error import HTTPError, URLError
 from ansible.module_utils._text import to_text, to_native
 from ansible.module_utils.urls import open_url, ConnectionError, SSLValidationError
 from ansible.plugins.lookup import LookupBase
+from ansible.utils.display import Display
 
-try:
-    from __main__ import display
-except ImportError:
-    from ansible.utils.display import Display
-    display = Display()
+display = Display()
 
 
 class LookupModule(LookupBase):