metabase.util.quick-task

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Namespace with helpers for quick tasks. Intended for quick, one-off tasks like re-syncing a table, fingerprinting a field, etc.

(ns metabase.util.quick-task
  (:require
   [metabase.plugins.classloader :as classloader])
  (:import
   (java.util.concurrent Callable Executors ExecutorService Future ThreadFactory)))

(set! *warn-on-reflection* true)

(defonce ^:private thread-factory
  (reify ThreadFactory
    (newThread [_ r]
      ;; Ensure that the classloader is in the current thread context so it gets passed on.
      (classloader/the-classloader)
      (doto (Thread. r)
        (.setName "table sync worker")
        (.setDaemon true)))))

(defonce ^:private executor

(delay (Executors/newFixedThreadPool 1 ^ThreadFactory thread-factory)))

Submit a task to the single thread executor. This will attempt to serialize repeated requests to sync tables. It obviously cannot work across multiple instances.

(defn submit-task!
  ^Future [^Callable f]
  (let [task (bound-fn [] (f))]
    (.submit ^ExecutorService @executor ^Callable task)))