Improvement to Langchain.logger

[andreibondarev]

Is your feature request related to a problem? Please describe.

• Instead of the method_missing approach, use the progname to set "[Langchain.rb]" in front of the logs.
• Enable a way to output logs to a specified file path. (@dferrazm)
• Within the Langchain::LLM::* classes, make sure the different Net::HTTP, Faraday or client libraries are using the global Langchain.logger configuration.
• Within the Langchain::Vectorsearch::* classes, make sure the different Net::HTTP, Faraday or client libraries are using the global Langchain.logger configuration.

[dferrazm]

• Instead of the method_missing approach, use the progname to set "[Langchain.rb]" in front of the logs.
• Enable a way to output logs to a specified file path.

☝️ Fixed by #796

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Within the Langchain::LLM::* classes, make sure the different Net::HTTP, Faraday or client libraries are using the global Langchain.logger configuration.

For that one ☝️ , I'll do in a different PR, since I still haven't gone through all the clients.

[ajsharp]

Would also be great if langchain's logger was compatible with the rails logger. Currently trying to assign the rails logger to the langchain logger throws an error: NoMethodError: undefined method `debug?' for nil

[andreibondarev]

Would also be great if langchain's logger was compatible with the rails logger. Currently trying to assign the rails logger to the langchain logger throws an error: NoMethodError: undefined method `debug?' for nil

Hey @ajsharp, is this how you're assigning it?

[1] pry(main)> Langchain.logger = Rails.logger
=> #<ActiveSupport::Logger:0x0000000144e950f8
...
[2] pry(main)> Langchain.logger.debug?
=> true

[ajsharp]

Sorry about this @andreibondarev -- this was an error on my part -- I was setting the logger in config/application.rb and I don't think the rails logger is initialized at that point. Setting it in an initializer fixes the issue. Sorry for the noise!