I cannot see my custom properties being logged to application insights only the message. Does it need additional setup?

Question

Doing something like that

Dictionary<string, string> properties = new Dictionary<string, string>()
{
     { "Prop1", "abc" },
     { "Prop2", "def" },
};
 _logger.LogInformation("CustomProperties", properties); //Logs only the string, dictionary content missing completely

//In Program.cs

builder.Services.AddApplicationInsightsTelemetry();

Appsettings.json

{

Answer 1

Hi @Valeriy Sudakov

_logger.LogInformation("CustomProperties", properties);

The issue relates the use of LoggerExtensions.LogInformation Method, to formats and writes an informational log message. You can change your code as below:

            Dictionary<string, string> properties = new Dictionary<string, string>()
            {
                 { "Prop1", "abc" },
                 { "Prop2", "def" },
            };
            _logger.LogInformation("CustomProperties {properties}", properties);

Then the result as below:

Or you can serialize the dictionary to a Json string, then log the result:

            var logmessage = System.Text.Json.JsonSerializer.Serialize(properties);

            _logger.LogInformation($"CustomProperties: {logmessage}"); 

The output as below:

---

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Answer 2

see docs:

https://learn.microsoft.com/en-us/dotnet/api/microsoft.extensions.logging.loggerextensions.loginformation?view=dotnet-plat-ext-7.0

_logger.LogInformation("CustomProperties {Prop1}, {Prop2}",  
     properties["Prop1", 
     properties["Prop2"]);