db.clj

(defrecord DatascriptS3Db [bucket key-name schema conn-ch]
  component/Lifecycle
  (start [this]
    (let [s3-conn-ch (chan 1 (map (s3-obj->conn schema)))
          conn-ch (chan)]
      (pipe (u/get-obj-ch bucket key-name) s3-conn-ch)
      (go-loop [conn nil]
        (let [conn* (if conn
                      conn
                      (<! s3-conn-ch))]
          (>! conn-ch conn*)
          (recur conn*)))
      (assoc this :conn-ch conn-ch)))
  (stop [this]
    (close! conn-ch)
    (dissoc this :conn-ch)))