✨ Improve msgbus internal API

backend/src/app/msgbus.clj

@@ -35,12 +35,12 @@
 
 (declare ^:private redis-connect)
 (declare ^:private redis-disconnect)
-(declare ^:private start-io-loop)
-(declare ^:private subscribe)
-(declare ^:private purge)
 (declare ^:private redis-pub)
 (declare ^:private redis-sub)
 (declare ^:private redis-unsub)
+(declare ^:private start-io-loop!)
+(declare ^:private subscribe-to-topics)
+(declare ^:private unsubscribe-channels)
 
 (defmethod ig/prep-key ::msgbus
   [_ cfg]
@@ -48,42 +48,68 @@
           :timeout (dt/duration {:seconds 30})}
          (d/without-nils cfg)))
 
+(s/def ::cmd-ch ::aa/channel)
+(s/def ::rcv-ch ::aa/channel)
+(s/def ::pub-ch ::aa/channel)
+(s/def ::state ::us/agent)
+(s/def ::pconn ::redis/connection)
+(s/def ::sconn ::redis/connection)
+(s/def ::msgbus
+  (s/keys :req [::cmd-ch ::rcv-ch ::pub-ch ::state ::pconn ::sconn ::wrk/executor]))
+
 (s/def ::buffer-size ::us/integer)
 
 (defmethod ig/pre-init-spec ::msgbus [_]
   (s/keys :req-un [::buffer-size ::redis/timeout ::redis/redis ::wrk/executor]))
 
 (defmethod ig/init-key ::msgbus
-  [_ {:keys [buffer-size] :as cfg}]
+  [_ {:keys [buffer-size executor] :as cfg}]
   (l/info :hint "initialize msgbus" :buffer-size buffer-size)
   (let [cmd-ch (a/chan buffer-size)
         rcv-ch (a/chan (a/dropping-buffer buffer-size))
         pub-ch (a/chan (a/dropping-buffer buffer-size) xform-prefix-topic)
-        state  (agent {} :error-handler #(l/error :cause % :hint "unexpected error on agent" ::l/async false))
-        cfg    (-> (redis-connect cfg)
+        state  (agent {})
+        msgbus (-> (redis-connect cfg)
                    (assoc ::cmd-ch cmd-ch)
                    (assoc ::rcv-ch rcv-ch)
                    (assoc ::pub-ch pub-ch)
-                   (assoc ::state state))]
+                   (assoc ::state state)
+                   (assoc ::wrk/executor executor))]
 
-    (start-io-loop cfg)
+    (us/verify! ::msgbus msgbus)
 
-    (with-meta
-      (fn [& {:keys [cmd] :as params}]
-        (a/go
-          (case cmd
-            :pub   (a/>! pub-ch params)
-            :sub   (a/<! (subscribe cfg params))
-            :purge (a/<! (purge cfg params))
-            (l/error :hint "unexpeced error on msgbus command processing" :params params))))
-      cfg)))
+    (set-error-handler! state #(l/error :cause % :hint "unexpected error on agent" ::l/async false))
+    (set-error-mode! state :continue)
+    (start-io-loop! msgbus)
+
+    msgbus))
+
+(defn sub!
+  [{:keys [::state ::wrk/executor] :as cfg} & {:keys [topic topics chan]}]
+  (let [done-ch (a/chan)
+        topics  (into [] (map prefix-topic) (if topic [topic] topics))]
+    (l/debug :hint "subscribe" :topics topics)
+    (send-via executor state subscribe-to-topics cfg topics chan done-ch)
+    done-ch))
+
+(defn pub!
+  [{::keys [pub-ch]} & {:as params}]
+  (a/go
+    (a/>! pub-ch params)))
+
+(defn purge!
+  [{:keys [::state ::wrk/executor] :as msgbus} chans]
+  (l/trace :hint "purge" :chans (count chans))
+  (let [done-ch (a/chan)]
+    (send-via executor state unsubscribe-channels msgbus chans done-ch)
+    done-ch))
 
 (defmethod ig/halt-key! ::msgbus
-  [_ f]
-  (let [mdata (meta f)]
-    (redis-disconnect mdata)
-    (a/close! (::cmd-ch mdata))
-    (a/close! (::rcv-ch mdata))))
+  [_ msgbus]
+  (redis-disconnect msgbus)
+  (a/close! (::cmd-ch msgbus))
+  (a/close! (::rcv-ch msgbus))
+  (a/close! (::pub-ch msgbus)))
 
 ;; --- IMPL
 
@@ -91,9 +117,8 @@
   [{:keys [timeout redis] :as cfg}]
   (let [pconn (redis/connect redis :timeout timeout)
         sconn (redis/connect redis :type :pubsub :timeout timeout)]
-    (-> cfg
-        (assoc ::pconn pconn)
-        (assoc ::sconn sconn))))
+    {::pconn pconn
+     ::sconn sconn}))
 
 (defn- redis-disconnect
   [{:keys [::pconn ::sconn] :as cfg}]
@@ -152,22 +177,6 @@
   (aa/with-closing done-ch
     (reduce #(unsubscribe-single-channel %1 cfg %2) state channels)))
 
-
-(defn- subscribe
-  [{:keys [::state executor] :as cfg} {:keys [topic topics chan]}]
-  (let [done-ch (a/chan)
-        topics  (into [] (map prefix-topic) (if topic [topic] topics))]
-    (l/debug :hint "subscribe" :topics topics)
-    (send-via executor state subscribe-to-topics cfg topics chan done-ch)
-    done-ch))
-
-(defn- purge
-  [{:keys [::state executor] :as cfg} {:keys [chans]}]
-  (l/trace :hint "purge" :chans (count chans))
-  (let [done-ch (a/chan)]
-    (send-via executor state unsubscribe-channels cfg chans done-ch)
-    done-ch))
-
 (defn- create-listener
   [rcv-ch]
   (redis/pubsub-listener
@@ -179,8 +188,8 @@
                    (when-not (a/offer! rcv-ch val)
                      (l/warn :msg "dropping message on subscription loop"))))))
 
-(defn start-io-loop
-  [{:keys [::sconn ::rcv-ch ::pub-ch ::state executor] :as cfg}]
+(defn start-io-loop!
+  [{:keys [::sconn ::rcv-ch ::pub-ch ::state ::wrk/executor] :as cfg}]
   (redis/add-listener! sconn (create-listener rcv-ch))
   (letfn [(send-to-topic [topic message]
             (a/go-loop [chans  (seq (get-in @state [:topics topic]))