Docs: Improve Logger documentations typed logger

[amirkaws]

What were you searching in the docs?

I am looking for the documentation to show me how to use typed logger, and interface based logger rather than Logger. static methods.

public class Function
{
    private static ILogger _logger;

    public Function()
    {
        _logger = Logger.Create<Function>();
    }

    [Logging(LogEvent = true)]
    public async Task<APIGatewayProxyResponse> FunctionHandler(APIGatewayProxyRequest apigwProxyEvent,
              ILambdaContext context)
    {
        _logger.LogInformation(new { LogLocation = "FunctionHandler" }, "Test Message");

        ...
    }
}

{
    "cold_start": true,
    "xray_trace_id": "1-61b7add4-66532bb81441e1b060389429",
    "function_name": "test",
    "function_version": "$LATEST",
    "function_memory_size": 128,
    "function_arn": "arn:aws:lambda:eu-west-1:12345678910:function:test",
    "function_request_id": "52fdfc07-2182-154f-163f-5f0f9a621d72",
    "timestamp": "2021-12-13T20:32:22.5774262Z",
    "level": "Information",
    "service": "lambda-example",
    "name": "HelloWorld.Function",
    "message": "Collecting payment",
    "sampling_rate": 0.7,
    "correlation_id": "correlation_id_value"
}

Is this related to an existing documentation section?

No response

How can we improve?

Add a section in documentation related to typed logger, and another one for dependency injection

Got a suggestion in mind?

No response

Acknowledgment

• I understand the final update might be different from my proposed suggestion, or refused.

[rahulpnath]

A couple of observations using the log method on the Logger instance

1. Throws an exception System.Reflection.TargetParameterCountException: Parameter count mismatch, when using the LogInformation with parameters

    _logger.LogInformation("Testing with parameter Log Information Method {cityName}", cityName);

   Have to explicitly pass the parameters as an object[] for it to work like below.

    _logger.LogInformation("Testing with parameter Log Information Method {cityName}", new[] { cityName });

2. Logged Parameters are not available in the output as destructured parameters.
   The above log statement outputs the below in CloudWatch

   {
    "cold_start": true,
    "xray_trace_id": "1-654bd325-0acb33237c954016773e537b",
    "function_name": "weathertest-LambdaEmptyFunction1FunctionGetWeather-zQceOL6olYxd",
    "function_version": "$LATEST",
    "function_memory_size": 256,
    "function_arn": "arn:aws:lambda:ap-southeast-2:189107071895:function:weathertest-LambdaEmptyFunction1FunctionGetWeather-zQceOL6olYxd",
    "function_request_id": "f32b5d3f-62eb-424c-9cbc-d5b0b48e3d0d",
    "timestamp": "2023-11-08T18:27:50.6013375Z",
    "level": "Information",
    "service": "service_undefined",
    "name": "LambdaEmptyFunction1.Function",
    "message": "Testing with parameter Log Information Method Brisbane"
   }

   I expected the cityName to be available in the log output.

Not sure if these are something that could be included as part of the documentation or am f I am missing something here? @amirkaws

[hjgraca]

Hi @rahulpnath thanks for raising the issue and thanks for the youtube video as well 😄 really cool.

So at the moment the way you add "addiitonal keys" is by calling the methods Logger.AppendKey or Logger.AppendKeys you can have a look in the docs.

The reason behind that approach was for the user experience to be the same across all Powertools runtimes.
We now believe that we need a more .NET way to do logging, we are in the process of creating an RFC which will be similar to what you are alluding to, essentially resembling what ILogger does or what Serilog does.

Any input or feedback will be greatly appreciated, we don't have anything public yet, so if you have any ideas would love to hear them

[hjgraca]

Discussion: #570

[hjgraca]

@rahulpnath and @amirkaws thanks for opening the issue and your comments

This is now supported in version 2 of Logger

You can now use ILogger or LoggerFactory to create a Powertools Logger Documentation

You can now also use Message templates to log structured logs of your objects Documenation

Logger.LogInformation("{@person}", person);

and to get the correct message format override the ToString of the Person class

 public override string ToString()
  {
      return $""{Name} and is {Age} years old"";
  }

this will result in:

{
    "level": "Information",
    "message": "Alan Adams and is 11 years old"
    "person": {
        "name": "Alan Adams",
        "age": 11,
        "address": {
            "street": "123 Main Street",
            "city": "Boston"
        }
    },
    ...
}

Using {} will do the ToString only

 _logger.LogInformation("Testing with parameter Log Information Method {cityName}", cityName);

{
    "level": "Information",
    "message": "Testing with parameter Log Information Method London",
    "cityName" : "London"
    ...
}