fix #434: dont fetch price-info too often

src/clj/commiteth/util/crypto_fiat_value.clj

@@ -1,66 +1,100 @@
 (ns commiteth.util.crypto-fiat-value
   (:require [mount.core :as mount]
+            [clj-time.core :as t]
+            [clojure.edn :as edn]
             [clojure.tools.logging :as log]
             [commiteth.config :refer [env]]
             [commiteth.util.util :refer [json-api-request]]))
 
 
-(defn fiat-api-provider []
+(defn- fiat-api-provider []
   (env :fiat-api-provider :coinmarketcap))
 
-
-(defn get-token-usd-price-cryptonator
+(defn- get-token-usd-price-cryptonator
   "Get current USD value for a token using cryptonator API"
   [tla]
+  (log/infof "%s: Getting price-data from Cryptonator" tla)
   (let [token (subs (str tla) 1)
-        url (str "https://api.cryptonator.com/api/ticker/"
-                 token
-                 "-usd")
+        url (format "https://api.cryptonator.com/api/ticker/%s-usd" token)
         m (json-api-request url)]
     (-> (get-in m ["ticker" "price"])
-        (read-string))))
+        (edn/read-string))))
 
-
-(def tla-to-id-mapping (atom {}))
-
-(defn make-tla-to-id-mapping
+(defn- make-tla-to-id-mapping
   "Coinmarketcap API uses it's own IDs for tokens instead of TLAs"
   []
-  (let [data (json-api-request "https://api.coinmarketcap.com/v1/ticker/?limit=0")]
-    (into {} (map
-              (fn [x] [(keyword (get x "symbol")) (get x "id")])
-              data))))
+  (->> (json-api-request "https://api.coinmarketcap.com/v1/ticker/?limit=0")
+       (map (fn [x] [(keyword (get x "symbol")) (get x "id")]))
+       (into {})))
 
-(defn get-token-usd-price-coinmarketcap
+(defn- get-token-usd-price-coinmarketcap
   "Get current USD value for a token using coinmarketcap API"
-  [tla]
-  (let [token-id (get @tla-to-id-mapping tla)
-        url (format "https://api.coinmarketcap.com/v1/ticker/%s" token-id)
-        data (json-api-request url)]
-    (-> (first data)
-        (get "price_usd")
-        (read-string))))
+  [tla token-id]
+  {:pre [(some? token-id)]}
+  (log/infof "%s: Getting price-data from CoinMarketCap (token-id %s)" tla token-id)
+  (-> (json-api-request (format "https://api.coinmarketcap.com/v1/ticker/%s" token-id))
+      (first)
+      (get "price_usd")
+      (edn/read-string)))
 
-(defn- get-price-fn []
-  (let [fns {:cryptonator get-token-usd-price-cryptonator
-                      :coinmarketcap get-token-usd-price-coinmarketcap}]
-    (get fns (fiat-api-provider))))
+(defrecord PriceInfo [tla usd date])
 
-(defn bounty-usd-value
-  "Get current USD value of a bounty. bounty is a map of token-tla (keyword) to value"
-  [bounty]
-  (let [get-token-usd-price (get-price-fn)]
-    (reduce + (map (fn [[tla value]]
-                     (let [usd-price (get-token-usd-price tla)]
-                       (* usd-price value)))
-                   bounty))))
+(defn recent? [price-info]
+  (t/after? (:date price-info) (t/minus (t/now) (t/minutes 5))))
 
+(defprotocol IFiatCryptoConverter
+  (start [_])
+  (convert-usd [_ tla amount]))
+
+(defrecord FiatCryptoConverter [provider state]
+  IFiatCryptoConverter
+  (start [_]
+    (when (= :coinmarketcap provider)
+      (swap! state assoc :tla->id (make-tla-to-id-mapping))))
+  (convert-usd [_ tla amount]
+    (if-let [recent-price-info (and (some-> (get-in @state [:price-info tla]) recent?)
+                                    ;; return actual price info
+                                    (get-in @state [:price-info tla]))]
+      (* (:usd recent-price-info) amount)
+      ;; if we don't have price-info we need to fetch & store it
+      (let [price (case provider
+                    :coinmarketcap (get-token-usd-price-coinmarketcap
+                                    tla
+                                    (get-in @state [:tla->id tla]))
+                    :cryptonator (get-token-usd-price-cryptonator tla))]
+        (swap! state assoc-in [:price-info tla] (->PriceInfo tla price (t/now)))
+        (* price amount)))))
 
 (mount/defstate
-  crypto-fiat-util
-  :start
-  (do
-    (reset! tla-to-id-mapping (make-tla-to-id-mapping))
-    (log/info "crypto-fiat-util started"))
-  :stop
-  (log/info "crypto-fiat-util stopped"))
+  fiat-converter
+  :start (let [provider (fiat-api-provider)]
+           (log/infof "Starting FiatCryptoConverter %s" provider)
+           (doto (->FiatCryptoConverter provider (atom {}))
+             (start)))
+  :stop  (log/info "Stopping FiatCryptoConverter"))
+
+;; public api ------------------------------------------------------------------
+
+(defn bounty-usd-value
+  "Get current USD value for the crypto-amounts passed as argument.
+  Example: {:ETH 123, :SNT 456}"
+  [crypto-amounts]
+  (->> crypto-amounts
+       (map (fn [[tla value]]
+              (convert-usd fiat-converter tla value)))
+       (reduce + 0)))
+
+
+(comment
+  (fiat-api-provider)
+
+  (def fc (->FiatCryptoConverter (fiat-api-provider) (atom {})))
+  (start fc)
+
+  (convert-usd fc :SNT 400)
+
+  (bounty-usd-value {:ETH 2 :ANT 2 :SNT 5})
+
+  (mount/start)
+
+  )