Make AzureCli class a singleton

data_safe_haven/external/__init__.py

@@ -1,5 +1,5 @@
 from .api.azure_api import AzureApi
-from .api.azure_cli import AzureCli
+from .api.azure_cli import AzureCliSingleton
 from .api.graph_api import GraphApi
 from .interface.azure_container_instance import AzureContainerInstance
 from .interface.azure_fileshare import AzureFileShare
@@ -8,7 +8,7 @@
 
 __all__ = [
     "AzureApi",
-    "AzureCli",
+    "AzureCliSingleton",
     "AzureContainerInstance",
     "AzureFileShare",
     "AzureIPv4Range",

data_safe_haven/external/api/azure_cli.py

@@ -7,7 +7,7 @@
 import typer
 
 from data_safe_haven.exceptions import DataSafeHavenAzureError
-from data_safe_haven.utility import LoggingSingleton
+from data_safe_haven.utility import LoggingSingleton, Singleton
 
 
 @dataclass
@@ -19,7 +19,7 @@ class AzureCliAccount:
     tenant_id: str
 
 
-class AzureCli:
+class AzureCliSingleton(metaclass=Singleton):
     """Interface to the Azure CLI"""
 
     def __init__(self) -> None:
@@ -32,6 +32,7 @@ def __init__(self) -> None:
         self.path = path
 
         self._account: AzureCliAccount | None = None
+        self._confirmed = False
 
     @property
     def account(self) -> AzureCliAccount:
@@ -62,6 +63,9 @@ def account(self) -> AzureCliAccount:
 
     def confirm(self) -> None:
         """Prompt user to confirm the Azure CLI account is correct"""
+        if self._confirmed:
+            return None
+
         account = self.account
         self.logger.info(
             f"name: {account.name} (id: {account.id_}\ntenant: {account.tenant_id})"
@@ -71,3 +75,5 @@ def confirm(self) -> None:
                 "Please use `az login` to connect to the correct Azure CLI account"
             )
             raise typer.Exit(1)
+
+        self._confirmed = True

data_safe_haven/infrastructure/stack_manager.py

@@ -12,7 +12,7 @@
 
 from data_safe_haven.config import Config
 from data_safe_haven.exceptions import DataSafeHavenAzureError, DataSafeHavenPulumiError
-from data_safe_haven.external import AzureApi, AzureCli
+from data_safe_haven.external import AzureApi, AzureCliSingleton
 from data_safe_haven.functions import replace_separators
 from data_safe_haven.infrastructure.stacks import DeclarativeSHM, DeclarativeSRE
 from data_safe_haven.utility import LoggingSingleton
@@ -31,7 +31,7 @@ def __init__(self, config: Config):
 
         # Ensure Azure CLI account is correct
         # This will be needed to populate env
-        AzureCli().confirm()
+        AzureCliSingleton().confirm()
 
     @property
     def env(self) -> dict[str, Any]:

data_safe_haven/utility/__init__.py

@@ -1,6 +1,7 @@
 from .enums import DatabaseSystem, SoftwarePackageCategory
 from .file_reader import FileReader
 from .logger import LoggingSingleton, NonLoggingSingleton
+from .singleton import Singleton
 from .types import PathType
 
 __all__ = [
@@ -9,5 +10,6 @@
     "LoggingSingleton",
     "NonLoggingSingleton",
     "PathType",
+    "Singleton",
     "SoftwarePackageCategory",
 ]

data_safe_haven/utility/logger.py

@@ -1,7 +1,7 @@
 """Standalone logging class implemented as a singleton"""
 import io
 import logging
-from typing import Any, ClassVar, Optional
+from typing import Any, ClassVar
 
 from rich.console import Console
 from rich.highlighter import RegexHighlighter
@@ -98,8 +98,6 @@ class LoggingSingleton(logging.Logger, metaclass=Singleton):
 
     date_fmt = r"%Y-%m-%d %H:%M:%S"
     rich_format = r"[log.time]%(asctime)s[/] [%(levelname)8s] %(message)s"
-    # Due to https://bugs.python.org/issue45857 we must use `Optional`
-    _instance: Optional["LoggingSingleton"] = None
 
     def __init__(self) -> None:
         super().__init__(name="data_safe_haven", level=logging.INFO)