redis.clj

(ns omega-red.redis
  "Represents a redis connection spec,
  so we can use it when using Carmine, unlike the
  regular `wcar*` macro, recommended in Carmine docs."
  (:require
    [com.stuartsierra.component :as component]
    [omega-red.protocol :as proto]
    [taoensso.carmine :as carmine]))


(defn get-redis-fn*
  "Finds actual function instance, based on a keyword.
  So:
  :hset -> taoensso.carmine/hset
  which then can be used as normal function"
  [fn-name-keyword]
  (ns-resolve 'taoensso.carmine (symbol fn-name-keyword)))


(def get-redis-fn (memoize get-redis-fn*))


(defn execute*
  [conn redis-fn+args]
  (let [[redis-fn & args] redis-fn+args]
    (carmine/wcar conn (apply (get-redis-fn redis-fn) args))))


(defn execute-pipeline*
  [conn redis-fns+args]
  (carmine/wcar conn
                :as-pipeline
                (mapv (fn [cmd+args]
                        (let [redis-fn (get-redis-fn (first cmd+args))]
                          (apply redis-fn (rest cmd+args))))
                      redis-fns+args)))


(defrecord Redis
  [pool spec conn]

  component/Lifecycle

  (start
    [this]
    (assoc this :conn {:pool pool :spec spec}))


  (stop
    [this]
    (assoc this :conn nil))


  proto/Redis

  (execute
    [_ redis-fn+args]
    (execute* conn redis-fn+args))


  (execute-pipeline
    [_ redis-fns+args]
    (execute-pipeline* conn redis-fns+args)))


(defn create
  [{:keys [host port]}]
  {:pre [(string? host)
         (number? port)]}
  (->Redis {} {:host host :port port} nil))