[#160] Add PostgreSQL appender (@yuliu-mdsol)

src/taoensso/timbre/appenders/3rd_party/postgresdb.clj

@@ -0,0 +1,78 @@
+(ns taoensso.timbre.appenders.3rd-party.postgresdb
+  "postgresql database appender"
+  (:require [clojure.java.jdbc  :as j]
+            [environ.core       :refer [env]]
+            [taoensso.timbre    :as timbre]
+            [taoensso.encore    :as encore])
+  (:import com.mchange.v2.c3p0.ComboPooledDataSource))
+
+(def default-args {:type "postgresql" :host "127.0.0.1" :port 5432})
+
+(defn pool [spec]
+  (let [cpds (doto (ComboPooledDataSource.)
+              (.setJdbcUrl (str "jdbc:" (:type spec) "://" (:host spec) ":" (:port spec) "/" (:database spec)))
+              (.setUser (:username spec))
+              (.setPassword (:password spec))
+              ;; expire excess connections after 30 minutes of inactivity:
+              (.setMaxIdleTimeExcessConnections (* 30 60))
+              ;; expire connections after 3 hours of inactivity:
+              (.setMaxIdleTime (* 3 60 60)))]
+    {:datasource cpds}))
+
+(defn connect [{:keys [server]}]
+  (let [args (merge default-args server)]
+     @(delay (pool args))))
+
+(def conn (atom nil))
+(defn ensure-conn [config] (swap! conn #(or % (connect config))))
+
+(defn log-message [data config]
+  (let [entry {:instant   (java.sql.Timestamp. (.getTime (:instant data)))
+               :level     (str  (:level         data))
+               :namespace (str  (:?ns-str       data))
+               :hostname  (str @(:hostname_     data))
+               :content   (str @(:vargs_        data))
+               :error     (str @(:?err_         data))}]
+    (ensure-conn config)
+    (j/insert! @conn :logs entry)))
+
+(defn pglog-appender
+  "Returns a postgresqlDB appender.
+  (pglog-appender {:server {:host \"127.0.0.1\" :port 5432}})
+
+  For log table creation and rollback, here are sql ddl script to use:
+
+  CREATE TABLE IF NOT EXISTS logs (
+      log_id bigserial primary key,
+      instant timestamp NOT NULL,
+      level varchar(20) NOT NULL,
+      namespace varchar(50) NOT NULL,
+      hostname varchar(30) NOT NULL,
+      content text NOT NULL,
+      error text NOT NULL
+  );
+
+  DROP TABLE IF EXISTS logs;
+
+  To automate database migration, you can use migratus for Leiningen,
+  or use ragtime for Boot.
+
+  Leiningen migratus (in profiles.clj)
+  ------------------------------------
+  :database-url \"postgresql://<db_username>:<db_password>@<db_servername>:<db_port>/<db_schema>\"
+
+  Boot ragtime (in build.boot)
+  ----------------------------
+  ragtime {:driver-class \"org.postgresql.Driver\"
+           :database (str \"jdbc:postgresql://<dbserver_name>:<db_port>/\"
+                        \"<db_schema>\"
+                        \"?user=<db_usernmae>\"
+                        \"&password=<db_password>\")})"
+
+  [db-config]
+  {:enabled?   true
+   :async?     false
+   :min-level  nil
+   :rate-limit nil
+   :output-fn  :inherit
+   :fn (fn [data] (log-message data db-config))})