✨ Improve internal API of retry mechanism

backend/src/app/loggers/audit.clj

@@ -200,22 +200,15 @@
       ;; NOTE: this operation may cause primary key conflicts on inserts
       ;; because of the timestamp precission (two concurrent requests), in
       ;; this case we just retry the operation.
-      (let [cfg    (-> cfg
-                       (assoc ::rtry/when rtry/conflict-exception?)
-                       (assoc ::rtry/max-retries 6)
-                       (assoc ::rtry/label "persist-audit-log"))
+      (let [tnow   (dt/now)
             params (-> params
+                       (assoc :created-at tnow)
+                       (assoc :tracked-at tnow)
                        (update :props db/tjson)
                        (update :context db/tjson)
                        (update :ip-addr db/inet)
                        (assoc :source "backend"))]
-
-        (rtry/invoke cfg (fn [cfg]
-                           (let [tnow   (dt/now)
-                                 params (-> params
-                                            (assoc :created-at tnow)
-                                            (assoc :tracked-at tnow))]
-                             (db/insert! cfg :audit-log params))))))
+        (db/insert! cfg :audit-log params)))
 
     (when (and (contains? cf/flags :webhooks)
                (::webhooks/event? event))
@@ -246,9 +239,13 @@
   "Submit audit event to the collector."
   [cfg params]
   (try
-    (let [event (d/without-nils params)]
+    (let [event (d/without-nils params)
+          cfg   (-> cfg
+                    (assoc ::rtry/when rtry/conflict-exception?)
+                    (assoc ::rtry/max-retries 6)
+                    (assoc ::rtry/label "persist-audit-log"))]
       (us/verify! ::event event)
-      (db/tx-run! cfg handle-event! event))
+      (rtry/invoke! cfg db/tx-run! handle-event! event))
     (catch Throwable cause
       (l/error :hint "unexpected error processing event" :cause cause))))
 

backend/src/app/rpc/retry.clj

@@ -6,8 +6,8 @@
 
 (ns app.rpc.retry
   (:require
+   [app.common.exceptions :as ex]
    [app.common.logging :as l]
-   [app.db :as db]
    [app.util.services :as sv])
   (:import
    org.postgresql.util.PSQLException))
@@ -15,12 +15,29 @@
 (defn conflict-exception?
   "Check if exception matches a insertion conflict on postgresql."
   [e]
-  (and (instance? PSQLException e)
-       (= "23505" (.getSQLState ^PSQLException e))))
+  (when-let [cause (ex/instance? PSQLException e)]
+    (= "23505" (.getSQLState ^PSQLException cause))))
 
 (def ^:private always-false
   (constantly false))
 
+(defn invoke!
+  [{:keys [::max-retries] :or {max-retries 3} :as cfg} f & args]
+  (loop [rnum 1]
+    (let [match? (get cfg ::when always-false)
+          result (try
+                   (apply f cfg args)
+                   (catch Throwable cause
+                     (if (and (match? cause) (<= rnum max-retries))
+                       ::retry
+                       (throw cause))))]
+      (if (= ::retry result)
+        (let [label (get cfg ::label "anonymous")]
+          (l/warn :hint "retrying operation" :label label :retry rnum)
+          (recur (inc rnum)))
+        result))))
+
+
 (defn wrap-retry
   [_ f {:keys [::sv/name] :as mdata}]
 
@@ -29,36 +46,10 @@
           matches?    (get mdata ::when always-false)]
       (l/dbg :hint "wrapping retry" :name name :max-retries max-retries)
       (fn [cfg params]
-        ((fn recursive-invoke [retry]
-           (try
-             (f cfg params)
-             (catch Throwable cause
-               (if (matches? cause)
-                 (let [current-retry (inc retry)]
-                   (l/wrn :hint "retrying operation" :retry current-retry :service name)
-                   (if (<= current-retry max-retries)
-                     (recursive-invoke current-retry)
-                     (throw cause)))
-                 (throw cause))))) 1)))
+        (-> cfg
+            (assoc ::max-retries max-retries)
+            (assoc ::when matches?)
+            (assoc ::label name)
+            (invoke! f params))))
     f))
 
-(defn invoke
-  [{:keys [::db/conn ::max-retries] :or {max-retries 3} :as cfg} f & args]
-  (assert (db/connection? conn) "invalid database connection")
-  (loop [rnum 1]
-    (let [match? (get cfg ::when always-false)
-          result (let [spoint (db/savepoint conn)]
-                   (try
-                     (let [result (apply f cfg args)]
-                       (db/release! conn spoint)
-                       result)
-                     (catch Throwable cause
-                       (db/rollback! conn spoint)
-                       (if (and (match? cause) (<= rnum max-retries))
-                         ::retry
-                         (throw cause)))))]
-      (if (= ::retry result)
-        (let [label (get cfg ::label "anonymous")]
-          (l/warn :hint "retrying operation" :label label :retry rnum)
-          (recur (inc rnum)))
-        result))))

common/src/app/common/exceptions.cljc

@@ -74,10 +74,9 @@
      [class cause]
      (loop [cause cause]
        (if (c/instance? class cause)
-         true
-         (if-let [cause (ex-cause cause)]
-           (recur cause)
-           false)))))
+         cause
+         (when-let [cause (ex-cause cause)]
+           (recur cause))))))
 
 ;; NOTE: idea for a macro for error handling
 ;; (pu/try-let [cause (p/await (get-object-data backend object))]