Merge pull request #134 from mping/async-mw-support

Support async middleware for ring async servers

Author: michaelklishin

Diff for: metrics-clojure-ring/src/metrics/ring/expose.clj

@@ -114,18 +114,31 @@
    (into {} (map #(render-metric % unit-context) (->> registry
                                                       (all-metrics)
                                                       (filter-metrics filter))))))
-
-(defn serve-metrics
-  ([request]
-     (serve-metrics request default-registry))
-  ([request registry]
-     (serve-metrics request registry false))
+(defn- serve-metrics*
   ([request registry {:keys [pretty-print? filter rate-unit duration-unit]}]
      (let [metrics-map (render-metrics registry filter (unit/build-options rate-unit duration-unit))
            json        (generate-string metrics-map {:pretty pretty-print?})]
        (-> (response json)
          (header "Content-Type" "application/json")))))
 
+(defn serve-metrics
+  ([request]
+    (let [^String filter (get-in request [:params :filter])]
+     (serve-metrics* request default-registry {:pretty-print? false
+                                               :filter filter
+                                               :rate-unit TimeUnit/SECONDS
+                                               :duration-unit TimeUnit/NANOSECONDS})))
+  ([request respond raise]
+    (let [^String filter (get-in request [:params :filter])]
+          (try            
+            (respond 
+              (serve-metrics* request default-registry {:pretty-print? false
+                                                      :filter filter
+                                                      :rate-unit TimeUnit/SECONDS
+                                                      :duration-unit TimeUnit/NANOSECONDS}))
+            (catch Exception e (raise e))))))
+
+
 (defn expose-metrics-as-json
   ([handler]
      (expose-metrics-as-json handler "/metrics"))
@@ -134,12 +147,22 @@
   ([handler uri registry]
     (expose-metrics-as-json handler uri registry {:pretty-print? false}))
   ([handler uri registry opts]
-    (fn [request]
-      (let [^String request-uri (:uri request)
-            ^String filter (get-in request [:params :filter])]
-        (if (or (.startsWith request-uri (sanitize-uri uri))
-                (= request-uri uri))
-          (serve-metrics request registry (merge {:filter filter
-                                                  :rate-unit TimeUnit/SECONDS
-                                                  :duration-unit TimeUnit/NANOSECONDS} opts))
-          (handler request))))))
+    (fn 
+      ([request]
+        (let [^String request-uri (:uri request)
+              ^String filter (get-in request [:params :filter])]
+          (if (or (.startsWith request-uri (sanitize-uri uri))
+                  (= request-uri uri))
+            (serve-metrics* request registry (merge {:filter filter
+                                                    :rate-unit TimeUnit/SECONDS
+                                                    :duration-unit TimeUnit/NANOSECONDS} opts))
+            (handler request))))
+      ([request respond raise]
+        (let [^String request-uri (:uri request)
+              ^String filter (get-in request [:params :filter])]
+          (if (or (.startsWith request-uri (sanitize-uri uri))
+                  (= request-uri uri))
+            (serve-metrics* request registry (merge {:filter filter
+                                                   :rate-unit TimeUnit/SECONDS
+                                                   :duration-unit TimeUnit/NANOSECONDS} opts))
+            (handler request respond raise)))))))

Diff for: metrics-clojure-ring/src/metrics/ring/instrument.clj

@@ -2,7 +2,7 @@
   (:require [metrics.core :refer [default-registry]]
             [metrics.counters :refer (counter inc! dec!)]
             [metrics.meters :refer (meter mark!)]
-            [metrics.timers :refer (timer time!)]
+            [metrics.timers :refer (timer time! start stop)]
             [clojure.string :as string])
   (:import [com.codahale.metrics MetricRegistry]))
 
@@ -51,23 +51,31 @@
      :times times
      :request-methods request-methods}))
 
-(defn handle-request [handler metrics request]
-  (let [{:keys [active-requests requests responses
-                schemes statuses times request-methods]} metrics]
-    (inc! active-requests)
-    (try
-      (let [request-method (:request-method request)
-            request-scheme (:scheme request)]
-        (mark! requests)
-        (mark-in! request-methods request-method)
-        (mark-in! schemes request-scheme)
-        (let [resp (time! (times request-method (times :other))
-                          (handler request))
-              ^{:tag "int"} status-code (or (:status resp) 404)]
-          (mark! responses)
-          (mark-in! statuses (int (/ status-code 100)))
-          resp))
-      (finally (dec! active-requests)))))
+(defn- time-request [thunk metrics request]
+    (let [{:keys [active-requests requests responses
+                  schemes statuses times request-methods]} metrics]
+      (inc! active-requests)
+      (try
+        (let [request-method (:request-method request)
+              request-scheme (:scheme request)]
+          (mark! requests)
+          (mark-in! request-methods request-method)
+          (mark-in! schemes request-scheme)
+          (let [resp (time! (times request-method (times :other))
+                            (thunk))
+                ^{:tag "int"} status-code (or (:status resp) 404)]
+            (mark! responses)
+            (mark-in! statuses (int (/ status-code 100)))
+            resp))
+        (finally (dec! active-requests)))))
+
+(defn handle-request 
+  ([handler metrics request]
+    (time-request #(handler request) metrics request))
+  ([handler metrics request respond raise]
+    (try 
+      (time-request #(handler request respond raise) metrics request)
+      (catch Exception e (raise e)))))
 
 (defn metrics-for
   [metrics-db prefix registry]
@@ -87,10 +95,15 @@
   ([handler]
    (instrument handler default-registry))
   ([handler ^MetricRegistry reg]
-   (fn [request]
-     (handle-request handler
-                     (ring-metrics reg {:prefix []})
-                     request))))
+   (fn 
+     ([request]
+      (handle-request handler
+                      (ring-metrics reg {:prefix []})
+                      request))
+     ([request respond raise]
+      (handle-request handler
+                      (ring-metrics reg {:prefix []})
+                      request respond raise)))))
 
 (defn instrument-by
   "Instrument a ring handler using the metrics returned by the `metrics-for`
@@ -107,8 +120,12 @@
    (instrument-by handler default-registry metrics-prefix))
   ([handler ^MetricRegistry reg metrics-prefix]
    (let [metrics-db (atom {})]
-     (fn [request]
-       (let [prefix (metrics-prefix request)]
-         (handle-request handler
-                         (metrics-for metrics-db prefix reg)
-                         request))))))
+    (fn 
+     ([request]
+      (handle-request handler
+                      (metrics-for metrics-db (metrics-prefix request) reg)
+                      request))
+     ([request respond raise]
+      (handle-request handler
+                      (metrics-for metrics-db (metrics-prefix request) reg)
+                      request respond raise))))))

Diff for: metrics-clojure-ring/test/metrics/test/instrument_test.clj

@@ -8,6 +8,9 @@
 (def dummy-handler (fn [req]
                      req))
 
+(def dummy-handler-async (fn [req respond raise] 
+                           (respond req)))
+
 (defn tracked? [^MetricRegistry reg metric]
   (->> (.getMetrics reg)
        (map (fn [[k v]] k))
@@ -54,6 +57,15 @@
 
       (app (mock/request :get "/yolo" {}))
 
+      (doseq [m expected-metrics]
+        (is (tracked? reg m)))))
+
+  (testing "instrument without custom prefix and async handler"
+    (let [reg (MetricRegistry. )
+          app (instrument dummy-handler-async reg)]
+
+      (app (mock/request :get "/yolo" {}) identity identity)
+
       (doseq [m expected-metrics]
         (is (tracked? reg m))))))
 
@@ -64,10 +76,20 @@
          (uri-prefix (mock/request :get "/foo/bar/baz")))))
 
 (deftest test-instrument-by-uri-prefix
-  (let [reg (MetricRegistry.)
-        app (instrument-by dummy-handler reg uri-prefix)]
+  (testing "instrument by uri prefix"
+    (let [reg (MetricRegistry.)
+          app (instrument-by dummy-handler reg uri-prefix)]
 
-    (app (mock/request :get "/yolo" {}))
+      (app (mock/request :get "/yolo" {}))
+
+      (doseq [m expected-metrics]
+        (is (tracked? reg (str "yolo." m))))))
 
-    (doseq [m expected-metrics]
-      (is (tracked? reg (str "yolo." m))))))
+  (testing "instrument by uri prefix and async handler"
+    (let [reg (MetricRegistry.)
+          app (instrument-by dummy-handler-async reg uri-prefix)]
+
+      (app (mock/request :get "/yolo" {}) identity identity)
+
+      (doseq [m expected-metrics]
+        (is (tracked? reg (str "yolo." m)))))))