What's the best way to format exceptions as JSON?

I've been experimenting with the logstash logback encoder. Messages come out right, but uncaught exceptions span multiple lines.

Are there best practices for structure logging from clojure?

Have you looked at using Throwable->map in core?

Might come in handy

hey guys, should I use clojure to webapps? (I’m coming from java - springboot and dropwizard background)… I’m loving clojure, but had read some places that clojure fits best for multi-threaded development…

@alexmiller: hey my friend! pleasure to see you here. does your book (clj applied) has database examples (connection pool, transactions handle etc)?

@alexmiller: I don't want to throw the exception. I want the logger to log uncaught exceptions on one line

preferably as json

@leo.ribeiro: the most common thing people do with Clojure is to write web apps

Clojure applied does not have anything about databases, sorry

@creese: I'm just saying that that function can convert an exception to data, which is easily jsonified

@leo.ribeiro, the new book from Wrox, Professional Clojure, covers Datomic to some depth. I haven’t read it myself but by the table of contents, it looks fairly comprehensive as a start.

@akiva thank you

@alexmiller thanks

is it currently possible to make an fdef spec where the :args are a tuple? when I instrument the implementation I get an exception about the args.

Evaluating (tuple-arg-fn [0 0]) leads to the following exception:

that isn't how `:args' works

that ':args' spec would work for function that takes two args that are numbers, not a function that takes a pair of numbers

@jmitchell: Maybe this is what you want?

(s/fdef tuple-arg-fn
  :args (s/cat :tuple (s/tuple int? int?))
  :ret int?)

wolfcore: macros haven't changed much, with the exception of clojure.spec

which just adds new techniques for processing arguments and reporting errors

I think the book is still a good starting point

thanks @tap and @hiredman. I follow what's going on now.

Anyone with compiled jar knowledge? Is there a way in Clojure to discover non-required namespaces (not required in any namespace), when it is in compiled jar?

I don't know of a thing that tells you that

tools.namespace I believe has tools to help you construct a graph of namespaces so it could get you some of the way there

Looks like it works only with source files

does the s/fdef for declare described in https://clojure.org/guides/spec#_macros allow valid input? i get an exception when i instrument it and try to run (declare x)

ognivo: You might want to look at https://github.com/weavejester/resauce

Do any of the clojure time libraries out there handle cron expressions and can provide a sequence of date objects or date strings in a range? Something like '* */30 * * *' => ('2016-05-05 00:00:00' '2016-05-05 00:30:00' ....)

@jmitchell: I think that example has fallen out of working due to changes in instrument. Macros take 2 extra implicit args and instrument is no longer working properly with them. However you should no longer call instrument on macros anyways as macros are always checked during macroexpansion