Hi Didier
The interceptor pattern is pretty tiny, certainly small enough to copy from
project to project if you wanted. You can see re-frame's implementation
here:
https://github.com/Day8/re-frame/blob/master/src/re_frame/interceptor.cljc
which
is only around 100 SLOC. That doesn't handle exceptions like Pedestal, but
shows the core of the idea.
On Mon, Oct 2, 2017 at 5:22 PM Didier <didi...@gmail.com> wrote:
> I can't emphasize enough the utility of the interceptor chain pattern, as
>> employed heavily in pedestal.
>>
>
> Interesting... Its almost like a workflow framework, but for simpler in
> code workflows. I'm reluctant to have a dependency on pedestal just for
> this though.
>
> On Sunday, 1 October 2017 21:00:31 UTC-7, Luke Burton wrote:
>
>>
>> On Sep 30, 2017, at 3:14 PM, Didier <did...@gmail.com> wrote:
>>
>> Is there another way to execute a set of complex steps which does not
>> rely on let and can be try/catched in the manner I describe?
>>
>>
>> I can't emphasize enough the utility of the interceptor chain pattern, as
>> employed heavily in pedestal.
>>
>> I use this *everywhere* now. I have code that interleaves interceptors
>> into a chain to augment them with timing information, audit logs, and more.
>> I have written code that maps a subset of an interceptor chain over a
>> cluster of machines, then reduces the results back down locally. Most
>> importantly, they are fantastically useful when it comes time to debug a
>> complex business process … you can swap interceptors in and out easily,
>> isolate stateful interceptors to enable better mocking during tests, and
>> more.
>>
>> Here's a basic application of interceptors. It's really not much code
>> considering what you get. This doesn't even scratch the surface of what
>> they can do.
>>
>> (ns interceptor.test
>> (:require
>> [io.pedestal.interceptor.chain :as chain]))
>>
>> (def step1
>> {:name :step1
>> :enter (fn [ctx]
>> (let [x "sheep"]
>> (assoc ctx :result x)))})
>>
>> (def step2
>> {:name :step2
>> :error (fn [ctx ex-info]
>> (println "so much for step2:" (:exception-type (ex-data
>> ex-info))))
>> :enter (fn [{:keys [result] :as ctx}]
>>
>> (println "time to transform" result "into a number")
>> (update ctx :result #(Long/parseLong %)))})
>>
>> (defn run []
>> (chain/execute {} [step1 step2]))
>>
>>
>> --
> You received this message because you are subscribed to the Google
> Groups "Clojure" group.
> To post to this group, send email to clojure@googlegroups.com
> Note that posts from new members are moderated - please be patient with
> your first post.
> To unsubscribe from this group, send email to
> clojure+unsubscr...@googlegroups.com
> For more options, visit this group at
> http://groups.google.com/group/clojure?hl=en
> ---
> You received this message because you are subscribed to the Google Groups
> "Clojure" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to clojure+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
>
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
---
You received this message because you are subscribed to the Google Groups
"Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to clojure+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
