JsonLayout: add includeAllProperties & excludeProperties

[ericanastas]

Here's an initial attempt at adding "AllEventProperties" functionality to JsonLayout as mentioned in issue #1686. This is the first time I've made a pull request on GitHub. So if I'm not following the proper procedure or conventions let me know.

I have few questions:

1. I'm using a for each loop to iterate over the the log event properties, but everywhere else it looks like there's been an effort to use a for loop to avoid allocating an Enumerator. There doesn't look like a way to access the items or keys in a dictionary by index though. Is there some other way I could optimize this?

2. LogEventInfo.Properties is an IDictionary<object,object>. How should the keys be converted into a string property names? Should I just use ToString() as I have now? When would the key of a property not be a string?

3. Any ideas on how to handle property values that are collections or objects? I'm guessing we wouldn't want to use reflection to read properties from object values due to the performance hit. However, for my use case I'd like it to be able to identify collection properties and have them returned as an array of values in the JSON rather then "System.Collections.Generic.List`1[System.String]".

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This change is

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Current coverage is 80% (diff: 100%)

Merging #1754 into master will increase coverage by <1%

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[304NotModified]

I don't this will work from the XML, yet!

See #1439 (but I won't support IList).

Is it possible to write an unit test for this, so we won't forget it? (and it will succeed if we rebase after #1439 has been finished)

[304NotModified]

Maybe we should integrate this with #1740 (injecting Json serializer) . What do you think?

[304NotModified]

I'm using a for each loop to iterate over the the log event properties, but everywhere else it looks like there's been an effort to use a for loop to avoid allocating an Enumerator. There doesn't look like a way to access the items or keys in a dictionary by index though. Is there some other way I could optimize this?

We try to use for loops if we found in tests that would benefit. I think we could loop over the keys in this case, but I doubt if that will be an improvement. TL;DR, it's fine with a foreach

LogEventInfo.Properties is an IDictionary<object,object>. How should the keys be converted into a string property names? Should I just use ToString() as I have now? When would the key of a property not be a string?

preferred to use the JsonSerializer of #1740?

update: we have to be careful to be backwardscompatibe.

Any ideas on how to handle property values that are collections or objects?

Also #1740?

[304NotModified]

Intent to release this nice feature into 4.4 :)

[304NotModified]

We need to do the docs in wiki right?

[304NotModified]

docs done:

https://github.com/NLog/NLog/wiki/JsonLayout

[AuthorProxy]

needs to update xsd schema now, cause The attribute is not declared

[304NotModified]

thanks @AuthorProxy , created a new issue for it: #2037

[304NotModified]

@AuthorProxy It seems that nlog.schema was up-to-date, but not the one on nlog-project.org. This has been fixed.

Have to find out how to do this automatically. (powershell script or something like that)