Format of JSON not as expected

[bjhogan]

Expected Behaviour

For an object Person, that has an Address I expect to see it logged like this -

When logging using Logger.LogInformation<Person>(person, "{Name} and is {Age} years old", new object[]{person.Name, person.Age}); I expect the output to look like -

"person": {
    "name": "Alan Adams",
    "age": 11,
    "address": {
        "street": "123 Main Street",
        "city": "Boston"
    }
},

Current Behaviour

Instead the output is -

"name": "Alan Adams",
"age": 11,
"address": {
    "street": "123 Main Street",
    "city": "Boston"
},

Person is lost.

Code snippet

using Amazon.Lambda.Core;
using AWS.Lambda.Powertools.Logging;

// Assembly attribute to enable the Lambda function's JSON input to be converted into a .NET class.
[assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))]

namespace ThreeSimpleWaysToLog;

public class Function

{
    [Logging(LogEvent = true, LoggerOutputCase = LoggerOutputCase.CamelCase)]
    public void FunctionHandler(string input, ILambdaContext context)
    {
        Person person = new Person { Name ="Alan Adams", Age = 11, Address = new Address{ Street = "123 Main Street",  City ="Boston" } };
        Logger.LogInformation<Person>(person, "{Name} and is {Age} years old", new object[]{person.Name, person.Age});

    }
}

public class Person 
{
    public string Name {get ; set;} 
    public int Age { get; set; }
    public Address Address { get; set; }
}
public class Address 
{
    public string Street { get; set; }
    public string City { get; set; }
}

Possible Solution

I would expect the log out to look the same as it does when using like this -

Logger.AppendKey("Person", person);
Logger.LogInformation("{Name} and is {Age} years old", new object[]{person.Name, person.Age});
Logger.RemoveKeys("Person");

The output from this is -

{
    "coldStart": true,
    "xrayTraceId": "1-642b077d-0e615d154a66119a5585838b",
    "person": {
        "name": "Alan Adams",
        "age": 11,
        "address": {
            "street": "123 Main Street",
            "city": "Boston"
        }
    },
    "functionName": "ThreeSimpleWaysToLog",
    "functionVersion": "$LATEST",
    "functionMemorySize": 256,
    "functionArn": "arn:aws:lambda:us-east-1:694977046108:function:ThreeSimpleWaysToLog",
    "functionRequestId": "5bf50f21-2c0e-4327-82df-fd0939bf6aa5",
    "timestamp": "2023-04-03T17:06:07.0296164Z",
    "level": "Information",
    "service": "ThreeSimpleWaysToLog",
    "name": "AWS.Lambda.Powertools.Logging.Logger",
    "message": "Alan Adams and is 11 years old"
}

The Person is clearly shown.

Steps to Reproduce

Deploy the code provided and invoke.

AWS Lambda Powertools for .NET version

latest

AWS Lambda function runtime

dotnet6

Debugging logs

No response

[hjgraca]

@bjhogan thanks for reporting. Having a look

[sliedig]

Related to #116

[amirkaws]

Hi @bjhogan, thanks for opening the issue. The extraKeys parameter in Logger.LogInformation(extraKeys, "message"), expect dictionary or a list of key/value pairs. So the object also be treated as a bag of key/value pair and will be logged in the root level. You can pass "person" object as value in combination with the key name to achieve the desired outcome.

var extraKeys = new { Person = person };
Logger.LogInformation(extraKeys, $"{person.Name} and is {person.Age} years old");

On a separate notes, we have already another issue https://github.com/awslabs/aws-lambda-powertools-dotnet/issues/166 to improve the documentation.