Adding extension point allowing subclasses to add more data to the json log

[posto]

Hi,

I'm working on a custom JSON Logstash Appender that would add some company-specific fields to the logged events. It would really help if JSONEventLayoutV1 would provide an extension point.

Please let me know what you think.

Thanks,
Dumitru

[posto]

Any chance to get this into the master? This issue is blocking our upgrade to latest logstash format :(

[lusis]

@posto oh sorry I just saw this. Taking a look now.

[lusis]

@posto is there any reason you wouldn't use MDC or NDC in this case? That's really what it was designed for. Maybe I'm missing something?

[posto]

@lusis -- MDC/NCD works for thread-bound data, for example for logging the user id making the request. These values would be set from the application code, because this is where it is available and it changes for each request.

In my case, I have a constant -- the application version, which never changes while the application is running. It's very similar to the @ version field that you already have. I find it quite hard to try to inject this constant as a MDC in every thread that runs in the app. It is much easier to extend your Layout, so that when the application starts -- it detects it's versions and always logs this.

My point is: MDC is for data that changes and what I want is to customize the logging output with yet another constant, similar to the @ version field.