clojure - 在 Clojure 中存储全局连接的正确方法是什么？

Question

我有以下文件作为从我的 API 端点访问我的数据库的访问点。在服务器的生命周期内维护单个连接(或连接池？)的正确方法是什么？

(ns my-api.repository
  (:require [clojure.java.jdbc :as sql]))

(defn some-query
  (sql/with-connection (System/getenv "DATABASE_URL")
    (sql/with-query-results results
      ;; You get the picture
      )))

Answer 1

DATABASE_URL存储，如果您使用 with-connection单个连接的宏。您可以使用 c3p0连接池库:

(defn pooled-spec
  "return pooled conn spec.
   Usage:
     (def pooled-db (pooled-spec db-spec))
     (with-connection pooled-db ...)"
  [{:keys [classname subprotocol subname user password] :as other-spec}]
  (let [cpds (doto (ComboPooledDataSource.)
               (.setDriverClass classname)
               (.setJdbcUrl (str "jdbc:" subprotocol ":" subname))
               (.setUser user)
               (.setPassword password))]
    {:datasource cpds}))