✨ Improve retry mechanism and macros

backend/src/app/db.clj

@@ -361,12 +361,20 @@
   [data]
   (org.postgresql.util.PGInterval. ^String data))
 
+(defn connection?
+  [conn]
+  (instance? Connection conn))
+
 (defn savepoint
   ([^Connection conn]
    (.setSavepoint conn))
   ([^Connection conn label]
    (.setSavepoint conn (name label))))
 
+(defn release!
+  [^Connection conn ^Savepoint sp ]
+  (.releaseSavepoint conn sp))
+
 (defn rollback!
   ([^Connection conn]
    (.rollback conn))

backend/src/app/loggers/audit.clj

@@ -23,8 +23,8 @@
    [app.loggers.webhooks :as-alias webhooks]
    [app.main :as-alias main]
    [app.rpc :as-alias rpc]
+   [app.rpc.retry :as rtry]
    [app.tokens :as tokens]
-   [app.util.retry :as rtry]
    [app.util.services :as-alias sv]
    [app.util.time :as dt]
    [app.worker :as wrk]
@@ -203,7 +203,8 @@
       ;; this case we just retry the operation.
       (rtry/with-retry {::rtry/when rtry/conflict-exception?
                         ::rtry/max-retries 6
-                        ::rtry/label "persist-audit-log"}
+                        ::rtry/label "persist-audit-log"
+                        ::db/conn (dm/check db/connection? conn-or-pool)}
         (let [now (dt/now)]
           (db/insert! conn-or-pool :audit-log
                       (-> params

backend/src/app/rpc/commands/comments.clj

@@ -19,8 +19,8 @@
    [app.rpc.commands.teams :as teams]
    [app.rpc.doc :as-alias doc]
    [app.rpc.quotes :as quotes]
+   [app.rpc.retry :as rtry]
    [app.util.pointer-map :as pmap]
-   [app.util.retry :as rtry]
    [app.util.services :as sv]
    [app.util.time :as dt]
    [clojure.spec.alpha :as s]))
@@ -309,7 +309,8 @@
 
       (rtry/with-retry {::rtry/when rtry/conflict-exception?
                         ::rtry/max-retries 3
-                        ::rtry/label "create-comment-thread"}
+                        ::rtry/label "create-comment-thread"
+                        ::db/conn conn}
         (create-comment-thread conn
                                {:created-at request-at
                                 :profile-id profile-id

backend/src/app/rpc/retry.clj

@@ -5,19 +5,20 @@
 ;; Copyright (c) KALEIDOS INC
 
 (ns app.rpc.retry
-  "A fault tolerance RPC middleware. Allow retry some operations that we
-  know we can retry."
   (:require
    [app.common.logging :as l]
-   [app.util.retry :refer [conflict-exception?]]
-   [app.util.services :as sv]))
+   [app.db :as db]
+   [app.util.services :as sv])
+  (:import
+   org.postgresql.util.PSQLException))
 
-(defn conflict-db-insert?
+(defn conflict-exception?
   "Check if exception matches a insertion conflict on postgresql."
   [e]
-  (conflict-exception? e))
+  (and (instance? PSQLException e)
+       (= "23505" (.getSQLState ^PSQLException e))))
 
-(def always-false (constantly false))
+(def ^:private always-false (constantly false))
 
 (defn wrap-retry
   [_ f {:keys [::matches ::sv/name] :or {matches always-false} :as mdata}]
@@ -40,3 +41,23 @@
                (throw cause))))) 1))
     f))
 
+(defmacro with-retry
+  [{:keys [::when ::max-retries ::label ::db/conn] :or {max-retries 3}} & body]
+  `(let [conn# ~conn]
+     (assert (or (nil? conn#) (db/connection? conn#)) "invalid database connection")
+     (loop [tnum# 1]
+       (let [result# (let [sp# (some-> conn# db/savepoint)]
+                       (try
+                         (let [result# (do ~@body)]
+                           (some->> sp# (db/release! conn#))
+                           result#)
+                         (catch Throwable cause#
+                           (some->> sp# (db/rollback! conn#))
+                           (if (and (~when cause#) (<= tnum# ~max-retries))
+                             ::retry
+                             (throw cause#)))))]
+         (if (= ::retry result#)
+           (do
+             (l/warn :hint "retrying operation" :label ~label :retry tnum#)
+             (recur (inc tnum#)))
+           result#)))))

backend/src/app/util/retry.clj

@@ -1,34 +0,0 @@
-;; This Source Code Form is subject to the terms of the Mozilla Public
-;; License, v. 2.0. If a copy of the MPL was not distributed with this
-;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
-;;
-;; Copyright (c) KALEIDOS INC
-
-(ns app.util.retry
-  "A fault tolerance helpers. Allow retry some operations that we know
-  we can retry."
-  (:require
-   [app.common.logging :as l])
-  (:import
-   org.postgresql.util.PSQLException))
-
-(defn conflict-exception?
-  "Check if exception matches a insertion conflict on postgresql."
-  [e]
-  (and (instance? PSQLException e)
-       (= "23505" (.getSQLState ^PSQLException e))))
-
-(defmacro with-retry
-  [{:keys [::when ::max-retries ::label] :or {max-retries 3}} & body]
-  `(loop [tnum# 1]
-     (let [result# (try
-                     ~@body
-                     (catch Throwable cause#
-                       (if (and (~when cause#) (<= tnum# ~max-retries))
-                         ::retry
-                         (throw cause#))))]
-       (if (= ::retry result#)
-         (do
-           (l/warn :hint "retrying operation" :label ~label :retry tnum#)
-           (recur (inc tnum#)))
-         result#))))

common/src/app/common/data/macros.cljc

@@ -108,6 +108,14 @@
           `(do ~@body)
           (reverse (partition 2 bindings))))
 
+(defmacro check
+  "Applies a predicate to the value, if result is true, return the
+  value if not, returns nil."
+  [pred-fn value]
+  `(if (~pred-fn ~value)
+     ~value
+     nil))
+
 (defmacro get-prop
   "A macro based, optimized variant of `get` that access the property
   directly on CLJS, on CLJ works as get."