Handle java.net.SocketExceptions that can be thrown for disconnecte…

…d clients (#17)

Fixes #16

CHANGELOG.md

@@ -2,12 +2,10 @@
 
 ## master (unreleased)
 
+* [#16](https://github.com/clojure-emacs/logjam/issues/16): handle `java.net.SocketException`s that can be thrown for disconnected clients.
 * Introduce `logjam.appender.default-event-size` configuration option.
-
-* Event filters: rename `:loggers` to `:loggers-allowlist`
 * [#13](https://github.com/clojure-emacs/logjam/issues/13): Event filters: introduce `:loggers-blocklist`.
-* Event filters: rename `:loggers` to `:loggers-allowlist`.
- * `:loggers` will remain supported.
+  * `:loggers` will remain supported.
 
 ## 0.2.0 (2024-01-04)
 

project.clj

@@ -20,7 +20,7 @@
                                        [com.taoensso/timbre "6.3.1" :exclusions [org.clojure/clojure]]
                                        [org.clojure/clojure "1.11.1"]]}
 
-             :dev {:plugins [[cider/cider-nrepl "0.44.0"]
+             :dev {:plugins [[cider/cider-nrepl "0.45.0"]
                              [refactor-nrepl "3.9.0"]]}
 
              :1.9 {:dependencies [[org.clojure/clojure "1.9.0"]]}

src/logjam/appender.clj

@@ -37,10 +37,18 @@
   (or (nil? filter-fn) (filter-fn event)))
 
 (defn- notify-consumers
+  "Calls the `:callback` present in each consumer.
+
+  If a SocketException is found, remove the consumer,
+  as it represents a disconnected nREPL client."
   [{:keys [consumers] :as appender} event]
-  (doseq [{:keys [callback filter-fn] :as consumer} (vals consumers)
+  (doseq [[consumer-id {:keys [callback filter-fn] :as consumer}] (some-> consumers deref)
           :when (filter-fn event)]
-    (callback consumer event))
+    (try
+      (callback consumer event)
+      (catch java.net.SocketException e ;; Issue #16
+        (.printStackTrace e)
+        (swap! consumers dissoc consumer-id))))
   appender)
 
 (defn- enqueue-event
@@ -56,11 +64,15 @@
 (defn add-consumer
   "Add the `consumer` to the `appender`."
   [appender {:keys [id filters] :as consumer}]
-  (assert (not (get-in appender [:consumers id]))
-          (format "Consumer %s already registered" id))
-  (assoc-in appender [:consumers id]
-            (-> (select-keys consumer [:callback :filters :id])
-                (assoc :filter-fn (event/search-filter (:levels appender) filters)))))
+  (when-let [consumers (some-> appender (get :consumers) deref)]
+    (assert (not (get consumers id))
+            (format "Consumer %s already registered" id)))
+  (swap! (:consumers appender)
+         assoc
+         id
+         (-> (select-keys consumer [:callback :filters :id])
+             (assoc :filter-fn (event/search-filter (:levels appender) filters))))
+  appender)
 
 (defn add-event
   "Add the `event` to the `appender`."
@@ -80,7 +92,7 @@
 (defn consumers
   "Return the consumers of the `appender`."
   [appender]
-  (vals (:consumers appender)))
+  (some-> appender :consumers deref vals))
 
 (defn consumer-by-id
   "Find the consumer of `appender` by `id`."
@@ -100,7 +112,7 @@
 (defn make-appender
   "Make a hash map appender."
   [{:keys [id filters levels logger size threshold]}]
-  (cond-> {:consumers {}
+  (cond-> {:consumers (atom {})
            :event-index {}
            :events nil
            :filters (or filters {})
@@ -116,7 +128,8 @@
 (defn remove-consumer
   "Remove the `consumer` from the `appender`."
   [appender consumer]
-  (update appender :consumers dissoc (:id consumer)))
+  (some-> appender :consumers (swap! dissoc (:id consumer)))
+  appender)
 
 (defn update-appender
   "Update the log `appender`."
@@ -132,10 +145,14 @@
 (defn update-consumer
   "Update the `consumer` of the `appender`."
   [appender {:keys [id filters] :as consumer}]
-  (update-in appender [:consumers id]
-             (fn [existing-consumer]
-               (assert (:id existing-consumer)
-                       (format "Consumer %s not registered" id))
-               (-> existing-consumer
-                   (merge (select-keys consumer [:filters]))
-                   (assoc :filter-fn (event/search-filter (:levels appender) filters))))))
+  (some-> appender
+          :consumers
+          (swap! update
+                 id
+                 (fn [existing-consumer]
+                   (assert (:id existing-consumer)
+                           (format "Consumer %s not registered" id))
+                   (-> existing-consumer
+                       (merge (select-keys consumer [:filters]))
+                       (assoc :filter-fn (event/search-filter (:levels appender) filters))))))
+  appender)