You could use: https://github.com/technomancy/robert-hooke
Its basically an AOP library for Clojure.
You can use "with-hooks-disabled" in your tests to disable the hooks that
have side effects.
On Friday, 11 November 2016 21:42:59 UTC-8, Shantanu Kumar wrote:
>
> Hi Tianxiang,
>
> In my experience a good way to decouple a non-trivial fn with metrics is
> to make the fn provide hooks for various events when metrics may be
> gathered.
>
> (defn nop [& args])
>
> (defn foo->bar [foo {:keys [on-foo on-bar] :or {on-foo nop on-bar nop} :as
> options}]
> (on-foo)
> (let [bar (produce-bar foo)]
> (on-bar)
> bar))
>
> Now, when unit testing for functionality of foo->bar you can pass {} as
> options, which wouldn't do any metrics collection. In actual usage, or for
> unit testing metrics collection, you would pass {:on-foo #(counter/inc!
> foo-counter) :on-bar #(counter/inc! bar-counter)} as options.
>
> This is a small fn, so it may not be apparent how can providing hooks be
> useful, but for large fns with multiple metrics-collection I've found
> providing hooks to be working quite well.
>
> HTH
>
> Shantanu
>
> On Saturday, 12 November 2016 08:24:40 UTC+5:30, Tianxiang Xiong wrote:
>>
>> What are some good ways of handling metric gathering (or, more generally,
>> AOP) in Clojure?
>>
>> Suppose we have an application in which there is a transformation
>> function, foo->bar. Every time a foo is input to foo->bar, we'd like to
>> increment the foo-counter. Every time a bar is produced, we'd like to
>> increment the bar-counter.
>>
>> To keep foo->bar pure, we can wrap foo->bar in another function like:
>>
>> (fn [& args]
>> (counter/inc! foo-counter)
>> (let [result (apply f args)]
>> (counter/inc! bar-counter)
>> result))
>>
>> But the side effect of incrementing counters makes it difficult to write
>> a unit test.
>>
>> I have a vague idea of what I'd *like* to see, which is the function
>> returning:
>>
>> - The result
>> - Some operation to be carried out, OR some data allowing the
>> receiver to carry out some operation?
>>
>> I'm sure this is not a new problem for Clojure applications; what are
>> some strategies for handling it?
>>
>
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