Introduce new handlers and refactor filters

[emmuhamm]

Description

Fixes #36

This PR Introduces a couple of changes that fixes #36

Added Throttling Filter (and demonstration)

• This dynamically filters out messages if many of them get sent. Logic exactly follows the C++ implementation. Defaults are also the same, with 30 seconds and 30 messages. Note that when adding the Throttle filter using get_daq_logger, it uses a boolean and so the 30s and 30msg can't be changed. This is fine for now but should be easy to make more customisable later.

Added support for Lstdout

• In ERS C++, Lstdout is the thread-safe version of stdout. The default logging implementation in Python is poggers as stdout is already threadsafe. Therefore, for this implementation we match HandlerType.Lstdout to just run for the stdout handler.
• This is done via stdout_handler.addFilter(HandleIDFilter([HandlerType.Stream, HandlerType.Lstdout])).
• Relevant changes in the code so HandleIDFilter supports multiple handlertypes to transmit with

Improves Filtering class logic and inheritance

• Refactored the old HandleIDFiltering code to a BaseHandlerFilter class which contains a lot of the checks on when to emit a message or not.
• Inherited by HandleIDFilter, makes it much easier to understand
• Also Inherited by ThrottleFilter as Throttle is technically a 'HandlerType', to reuse the checking logic

Move away from string based log level matching to enum-based log level matching

• When developing, there was a bug where using StreamHandler would break the ERS functionality.
• This is because running StreamHandler modifies the record via the LoggingFormatter, and previously the Filter uses level_to_ers_var.get(record.levelname)), which would now contain erroneous whitespace and matching would fail
• Moved from "DEBUG" to logging.DEBUG fixes this

Improves logging of the logging framework

• in OKS, the ERS variables are of the form "erstrace,throttle,lstdout"
• ERSTrace is no longer supported, so a debug message is sent via a logger in daqpytools to reveal this
• If the variable is "erstrace,throttle,random", where 'random' is not supported, the logger will send a warning message.

TODO

• Fix the comments @emmuhamm left in the code
• Run linter

Type of change

• Documentation (non-breaking change that adds or improves the documentation)
• New feature or enhancement (non-breaking change which adds functionality)
• Optimization (non-breaking change that improves code/performance)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (whatever its nature)

Testing checklist

• Unit tests pass (e.g. dbt-build --unittest)
• Minimal system quicktest passes (pytest -s minimal_system_quick_test.py)
• Full set of integration tests pass (daqsystemtest_integtest_bundle.sh)
• Python tests pass if applicable (e.g. python -m pytest)
• Pre-commit hooks run successfully if applicable (e.g. pre-commit run --all-files)

How to test the changes

• Check out this branch on the latest nightly
• Run:
  • daqpytools-logging-demonstrator -r
    • Should see the normal messages
  • daqpytools-logging-demonstrator -r --throttle
    • Demonstration of throttling. Should see a bunch of message print out and then throttled, a 30s wait, and then more messages and throttling
  • daqpytools-logging-demonstrator -s --handlertypes
    • this enables the stream handler (stdout + stderr)
    • Should see the usual example messages, and then the ERS messages going through
    • You should see anything that has lstdout be printed via the stdout handler
    • NOTE there will be duplicates anytime stdout + stderr is used in the demonstrator (eg in the example messages). This is documented in [Bug]: StreamHandler log levels are weirdly being overridden #44, and beyond the scope of this PR.

Further checks

• Code is commented where needed, particularly in hard-to-understand areas
• Code style is correct (dbt-build --lint, and/or see https://dune-daq-sw.readthedocs.io/en/latest/packages/styleguide/)
• If applicable, new tests have been added or an issue has been opened to tackle that in the future.
  (Indicate issue here: # (issue))

[emmuhamm]

Discuss if we want to make it customizable here

[emmuhamm]

After discussion, it is decided to leave as is for now. Can discuss with Marco later on to get his opinion though

[emmuhamm]

This is moved from the bottom of the file to up here so I can initialise the daqpytools logger

[emmuhamm]

I should note that while Lstdout is defined, I have not defined Lstderr just yet as it isnt used in any of the OKS configs as far as I can see.

Should be easy enough to implement. Do you want me to?

[emmuhamm]

Hi @PawelPlesniak, in the interest of timing and availability I'll ask for your review today before I leave. The overall functionality exists and works as expected.

Theres a few minor improvements here and there that I've commented about, but they shouldn't affect the functionality. Theres also a couple where I ask for input.

But yeah, wouldbe great if you can take a look at the code already + the functionality, and lmk what you think