Nlog: Formatting properties

[ThomasArdal]

I have a question regarding the formatting of the log message. If I log the following:

IList<string> list = new List<string>();
list.Add("A");
list.Add("B");
list.Add("C");
logManager.Fatal("List Properties {data}", list);

Using the default layout, I get a nicely formatted log message:

List Properties "A", "B", "C"

I'm storing all properties on each log message in a separate store. In my target, I iterate through the Properties property on LogEventInfo and store each property. My challenge here is that I store both they key and value as a string and simply call the ToString-method on each item. This result in the following being stored:

data = System.Collections.Generic.List`1[System.String]

In other places in my code, I'm using different layout renderers to generate a correct username, machine name, etc. But can I somehow use a generic renderer, similar to the one NLog uses for the log message? Would like to render all property values, without knowing what's inside each value really.

[304NotModified]

I think you're looking for the default IValueFormatter.

example:

c# var valueFormatter = ConfigurationItemFactory.Default.ValueFormatter; var sb = new StringBuilder(); valueFormatter.FormatValue(list, null, CaptureType.Normal, null, sb); var text = sb.ToString();

[snakefoot]

I guess you can do this:

c# string ConvertToString(object value) { if (Convert.GetTypeCode(value)==TypeCode.Object && value is System.Collections.IEnumerable) { var sb = new StringBuilder(); // Consider saving for reuse NLog.Config.ConfigurationItemFactory.Default.ValueFormatter.FormatValue(value, null, NLog.MessageTemplates.CaptureType.Normal, null, sb); return sb.ToString(); } return value?.ToString(); }

[304NotModified]

yes 8 seconds earlier 😄

[snakefoot]

But mine has less overhead for non-collections :)

[304NotModified]

Simple vs optimized example 👍

[ThomasArdal]

@304NotModified @snakefoot You guys rock. I can see how the second proposal will be good for a list, but I was chasing a solution working for everything really.

[snakefoot]

@ThomasArdal The second option will work for "everything". What do you feel that is missing?

[ThomasArdal]

Maybe I am missing something. Will it work for non-IEnumerable types?

[snakefoot]

Maybe I am missing something. Will it work for non-IEnumerable types?

As you can read from the very simple code-snippet, then it will call ToString on non-IEnumerable types.

Are you looking for JSON serialization? (Doesn't happen by default for message-templates)

[ThomasArdal]

Nope, but I guess NLog.Config.ConfigurationItemFactory.Default.ValueFormatter will handle enumerables and anything else already supported on the log message.

[snakefoot]

ValueFormatter will handle enumerables and anything else already supported on the log message.

Yes ValueFormatter will handle everything. But to avoid always allocating a StringBuilder (even for string-values), then I have made it a special case for IEnumerable-only.

[snakefoot]

@ThomasArdal Guess the issue can be closed as Resolved?

[ThomasArdal]

Absolutely 👍