Hystrix-clj IllegalStateException when using collapsers

[dinedal]

Using a very simple example:

(defcommand foo [a] (+ 1 a))
(defcollapser fooz (collapse [arg-lists] (instantiate foo (map first arg-lists))) (map [arg-lists batch-result] batch-result))

Calling (fooz [1]) raises:

java.lang.RuntimeException: HystrixCollapser$0 HystrixCollapser failed while executing.
    at com.netflix.hystrix.HystrixCollapser.execute(HystrixCollapser.java:302)
    at com.netflix.hystrix.core.proxy$com.netflix.hystrix.HystrixCollapser$0.execute(Unknown Source)
    at com.netflix.hystrix.core$execute.doInvoke(core.clj:465)
    at clojure.lang.RestFn.applyTo(RestFn.java:139)
    at clojure.core$apply.invoke(core.clj:619)
...
Caused by: java.lang.IllegalStateException: HystrixRequestContext.initializeContext() must be called at the beginning of each request before RequestVariable functionality can be used.
    at com.netflix.hystrix.strategy.concurrency.HystrixRequestVariableDefault.get(HystrixRequestVariableDefault.java:79)
    at com.netflix.hystrix.strategy.concurrency.HystrixRequestVariableHolder.get(HystrixRequestVariableHolder.java:68)
    at com.netflix.hystrix.HystrixCollapser.getCollapserForUserRequest(HystrixCollapser.java:392)
    at com.netflix.hystrix.HystrixCollapser.queue(HystrixCollapser.java:321)
    at com.netflix.hystrix.core.proxy$com.netflix.hystrix.HystrixCollapser$0.queue(Unknown Source)
    at com.netflix.hystrix.HystrixCollapser.execute(HystrixCollapser.java:290)
    ... 30 more

[benjchristensen]

Yes, as per the error message Collapsers are one of the things that needs a HystrixRequestContext to work.

HystrixRequestContext.initializeContext() must be called at the beginning of each request before RequestVariable functionality can be used.

You can find documentation on the subject here: https://github.com/Netflix/Hystrix/wiki/How-To-Use#wiki-RequestContextSetup

[dinedal]

Ah, in that case, I'll try my hand at adding that in

[daveray]

Also see the request context test fixture in the hystrix-clj tests for an example: https://github.com/Netflix/Hystrix/blob/master/hystrix-contrib/hystrix-clj/src/test/clojure/com/netflix/hystrix/core_test.clj