Util to put data into a temporary file and schedule it for deletion after a specified time period. Currently used to store card's rows data when sending notification since it can be large and we don't want to keep it in memory. | (ns metabase.notification.payload.temp-storage (:require [clojure.java.io :as io] [metabase.util.random :as random] [taoensso.nippy :as nippy]) (:import (java.io File) (java.util.concurrent Executors ScheduledThreadPoolExecutor TimeUnit))) |
(set! *warn-on-reflection* true) | |
(def ^:private temp-file-lifetime-seconds (* 5 60)) | |
(def ^:private temp-dir
(delay
(let [dir (io/file (System/getProperty "java.io.tmpdir")
(str "metabase-notification-" (random/random-name)))]
(.mkdirs dir)
(.deleteOnExit dir)
dir))) | |
(def ^:private deletion-scheduler
(delay
(Executors/newScheduledThreadPool 1))) | |
Schedule file for deletion after specified seconds. | (defn- schedule-deletion!
[^File file seconds]
(.schedule ^ScheduledThreadPoolExecutor @deletion-scheduler
^Callable (fn []
(when (.exists file)
(io/delete-file file true)))
^Long seconds
TimeUnit/SECONDS)) |
(defn- temp-file
[]
(doto (File/createTempFile "notification-" ".npy" @temp-dir)
(.deleteOnExit))) | |
(defn- write-to-file [^File file data] (nippy/freeze-to-file file data)) | |
(defn- read-from-file
[^File file]
(when (.exists file)
(nippy/thaw-from-file file))) | |
(.addShutdownHook
(Runtime/getRuntime)
(Thread. ^Runnable (fn []
(when @deletion-scheduler
(.shutdown ^ScheduledThreadPoolExecutor @deletion-scheduler))))) | |
------------------------------------------------------------------------------------------------;; Public APIs ;; ------------------------------------------------------------------------------------------------;; | |
Write data to a temporary file and schedule it for deletion after a specified time period. The file will be automatically deleted after the given number of seconds. Returns a derefable object that, when dereferenced, reads and returns the data from the temporary file. Arguments: data - The data to write to the temporary file seconds - Optional. Number of seconds before file deletion (default: is [[temp-file-lifetime-seconds]]) | (defn to-temp-file!
([data]
(to-temp-file! data temp-file-lifetime-seconds))
([data seconds]
(let [f (temp-file)]
(schedule-deletion! f seconds)
(write-to-file f data)
(reify
clojure.lang.IDeref
(deref [_] (read-from-file f)))))) |