Stack traces in (error) logs

[soxofaan]

(Follow-up issue for #455)

As mentioned in #455 putting full error stack traces in log messages is not a good idea, we should spec out a separate field for that.

[m-mohr]

Hmm, while I like getting rid of the stack traces in messages, I'm not sure whether they actually need to be exposed to users?
Can't you just generate a unique per log, put it in the id field and store the stack trace internally?

[jdries]

I think they should be exposed. We have one user segment of advanced coders that are used to dealing with stack traces. Their main criticism of openEO is that it's a 'black box', which makes them feel out of control. Giving the possibility to see stack traces would make a connection to the open source code which they can then inspect and even improve.

There's also the case of UDF's: there it is in fact the user code that can generate stack traces, so they need to see them to resolve issues.

[m-mohr]

Okay, I'll buy that. UDFs is a really compelling argument. Then let's find a definition for it.