Improve Pulumi Logger behaviour

[jemrobinson]

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⤴️ Summary

• Make LoggingSingleton inherit from Singleton metaclass
• Make LoggingSingleton a logging.logger (so line-by-line tracebacks will work correctly)

🌂 Related issues

🔬 Tests

Tested on running deployment

[JimMadge]

I like this, the singleton metaclass looks really clean and simple 👍.

I don't think I've used a metaclass before 👀.

[jemrobinson]

Still has a problem that you can't use logging.getLogger("data_safe_haven") as this will return a logging.Logger not LoggingSingleton so type-hinting would break if you call logging.getLogger().custom_function().

Hopefully using logger = LoggingSingleton() or simply LoggingSingleton().info("my message") is sufficiently easy syntax to understand.