Interceptor compile gets called too many times

[kennyjwilli]

I added a println to my interceptor's :compile function and it prints 4 times when I expected it to print 2 times.

Example code:

(ns compute.http-api.example
  (:require
    [clojure.spec.alpha :as s]
    [reitit.http :as http]
    [reitit.ring :as ring]
    [reitit.http.spec :as spec]
    [reitit.interceptor.sieppari :as sieppari]
    [spec-tools.spell :as spell]))

(s/def ::session-interceptor
  (s/keys :opt-un [::session]))

(def routes
  [["/ping" {:session {}
             :get     (fn [ctx]
                        (prn "ping")
                        {:status  200
                         :body    "pong2"
                         :headers {}})}]])

(def session-interceptor
  {:name    ::session
   :spec    ::session-interceptor
   :compile (fn [{:keys [session]} _]
              (prn "here")
              (when session
                {:enter (fn session-interceptor-enter [ctx]
                          (println "enter")
                          ctx)
                 :leave (fn session-interceptor-leave [ctx]
                          (println "leave")
                          ctx)}))})

(def app
  (http/ring-handler
    (http/router
      routes
      {:data             {:interceptors [session-interceptor]}
       :reitit.spec/wrap spell/closed
       :validate         spec/validate})
    (ring/create-default-handler)
    {:executor sieppari/executor}))

The output when loading this namespace is:

Loading src/compute/http_api/example.clj... 
"here"
"here"
"here"
"here"
Loaded

From the compile routes, it looks like there are only the two routes: one :get that I defined and one generated :options.

[["/ping"
  {:interceptors [{:name :compute.http-api.example/session,
                   :spec :compute.http-api.example/session-interceptor,
                   :compile #object[compute.http_api.example$fn__19986
                                    0x161124a7
                                    "compute.http_api.example$fn__19986@161124a7"]}],
   :session {:store "asd"},
   :get {:handler #object[compute.http_api.example$fn__19983 0x17267d23 "compute.http_api.example$fn__19983@17267d23"]}}
  #reitit.ring.Methods{:get #reitit.http.Endpoint{:data {:interceptors [{:name :compute.http-api.example/session,
                                                                         :spec :compute.http-api.example/session-interceptor,
                                                                         :compile #object[compute.http_api.example$fn__19986
                                                                                          0x161124a7
                                                                                          "compute.http_api.example$fn__19986@161124a7"]}],
                                                         :session {:store "asd"},
                                                         :handler #object[compute.http_api.example$fn__19983
                                                                          0x17267d23
                                                                          "compute.http_api.example$fn__19983@17267d23"]},
                                                  :interceptors [#reitit.interceptor.Interceptor{:name :compute.http-api.example/session,
                                                                                                 :enter #object[compute.http_api.example$fn__19986$session_interceptor_enter__19988
                                                                                                                0x61f75747
                                                                                                                "compute.http_api.example$fn__19986$session_interceptor_enter__19988@61f75747"],
                                                                                                 :leave #object[compute.http_api.example$fn__19986$session_interceptor_leave__19990
                                                                                                                0x2c9a9ac0
                                                                                                                "compute.http_api.example$fn__19986$session_interceptor_leave__19990@2c9a9ac0"],
                                                                                                 :error nil,
                                                                                                 :spec :compute.http-api.example/session-interceptor}
                                                                 #reitit.interceptor.Interceptor{:name :reitit.interceptor/handler,
                                                                                                 :enter #object[reitit.interceptor$eval4369$fn__4370$fn__4371
                                                                                                                0x33b1b7e8
                                                                                                                "reitit.interceptor$eval4369$fn__4370$fn__4371@33b1b7e8"],
                                                                                                 :leave nil,
                                                                                                 :error nil,
                                                                                                 :reitit.interceptor/handler #object[compute.http_api.example$fn__19983
                                                                                                                                     0x17267d23
                                                                                                                                     "compute.http_api.example$fn__19983@17267d23"]}],
                                                  :queue #object[clojure.lang.PersistentQueue
                                                                 0x4d0b5502
                                                                 "clojure.lang.PersistentQueue@66c34d0d"],
                                                  :handler nil,
                                                  :path "/ping",
                                                  :method :get},
                       :head nil,
                       :post nil,
                       :put nil,
                       :delete nil,
                       :connect nil,
                       :options #reitit.http.Endpoint{:data {:interceptors [{:name :compute.http-api.example/session,
                                                                             :spec :compute.http-api.example/session-interceptor,
                                                                             :compile #object[compute.http_api.example$fn__19986
                                                                                              0x161124a7
                                                                                              "compute.http_api.example$fn__19986@161124a7"]}],
                                                             :session {:store "asd"},
                                                             :no-doc true,
                                                             :handler #object[reitit.ring$fn__4906$fn__4915
                                                                              0x60b23b5b
                                                                              "reitit.ring$fn__4906$fn__4915@60b23b5b"]},
                                                      :interceptors [#reitit.interceptor.Interceptor{:name :compute.http-api.example/session,
                                                                                                     :enter #object[compute.http_api.example$fn__19986$session_interceptor_enter__19988
                                                                                                                    0x131f5d21
                                                                                                                    "compute.http_api.example$fn__19986$session_interceptor_enter__19988@131f5d21"],
                                                                                                     :leave #object[compute.http_api.example$fn__19986$session_interceptor_leave__19990
                                                                                                                    0x59471641
                                                                                                                    "compute.http_api.example$fn__19986$session_interceptor_leave__19990@59471641"],
                                                                                                     :error nil,
                                                                                                     :spec :compute.http-api.example/session-interceptor}
                                                                     #reitit.interceptor.Interceptor{:name :reitit.interceptor/handler,
                                                                                                     :enter #object[reitit.interceptor$eval4369$fn__4370$fn__4371
                                                                                                                    0x4e73eb2e
                                                                                                                    "reitit.interceptor$eval4369$fn__4370$fn__4371@4e73eb2e"],
                                                                                                     :leave nil,
                                                                                                     :error nil,
                                                                                                     :reitit.interceptor/handler #object[reitit.ring$fn__4906$fn__4915
                                                                                                                                         0x60b23b5b
                                                                                                                                         "reitit.ring$fn__4906$fn__4915@60b23b5b"]}],
                                                      :queue #object[clojure.lang.PersistentQueue
                                                                     0x56f5cdc1
                                                                     "clojure.lang.PersistentQueue@1aee94c2"],
                                                      :handler nil,
                                                      :path "/ping",
                                                      :method :options},
                       :trace nil,
                       :patch nil}]]

[ikitommi]

Hi. The interceptors are first compiled on reitit.http/router creation and second on reitit.http/ring-handler, which effectively doubles the compile times. This is needed as the ring-handler adds new route data &/ router options like the top-level interceptors and info about the executor - the interceptors COULD use this added data at compile-time to compile differently.

I think this is inconvenient, but does not effect runtime performance and should not matter a lot when creating a router.

If you think differently, please reopen and let's see if/how this could be changed.