Allow for the UserLogDefaultLogLevel to be set independent of system logs

[VineethReyya]

Issue describing the changes in this PR

Added --flag userLogLevel to set UserLogDefaultLogLevel without having to set the default log level, and without having to also set the SystemLogDefaultLogLevel to the same value.

resolves #4295

Pull request checklist

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• I have added all required tests (Unit tests, E2E tests)

[VineethReyya]

@liliankasem could you review the changes when have a moment.

Thanks

[liliankasem]

Maybe add that the default level for user logs is Information

[liliankasem]

Thanks, did you also investigate option (b) in my proposal? It would be good to see if that works?

Second, can you validate this works for all language workers?

I am still on the fence between a flag or env var for this

[VineethReyya]

@liliankasem

If we set "AzureFunctionsJobHost__Logging__LogLevel__Function" to 'debug' in local.settings.json or also use as an environment variable: Its showing debug logs for dotnet worker (if we set minimum level in program.cs), dotnet, Node, Python without depending on host.json.
For Python changes PFB screenshot: using "AzureFunctionsJobHost__Logging__LogLevel__Function": "Debug" in local.settings.json file

()

The changes were made to setup the value of UserLoglevel and systemLogLevel be different by using --userLoglevel flag to show logs based on loglevel is not working. it's still depending on host.json

can i set the value of 'AzureFunctionsJobHost__Logging__LogLevel__Function' as UserLogDefaultLogLevel instead of --userLogLevel flag?

[VineethReyya]

@liliankasem added new changes and tests. could you provide review.
Thanks

[liliankasem]

@liliankasem added new changes and tests. could you provide review. Thanks

Sorry I didn't mean for you to remove the implementation for the --userLogLevel flag, just that we should decide which approach.

@aishwaryabh @mattchenderson @soninaren - can you share thoughts on what you think here?

a) We can provide a flag for users to set on func start => --userLogLevel

b) We can provide an environment variable that can be set in local.settings.json or in local env => ``

c) We can use the existing host.json logging properties. We know that a Function log category exists already, we can utilize that here. This might be a little more complicated in code as we would want to do something like:

• if default is set, and Function is not set == set default value for both user and system
• if defailt is not set, and Function is set == set user log value to Function
• if default is set, and Functionis set == usedefaultfor system andFunction` for user logs

    "logLevel": {
      "default": "Warning",
      "Host.Aggregator": "Trace",
      "Host.Results": "Information",
      "Function": "Information" // use this to set user log level
    }

I am thinking we do both a and c - where users can utilize the host config file or they can set the flag with a func start command as a one off debug situation. Thoughts?

@VineethReyya lets hold off on more changes until we have consensus with the team, thanks!