add slack appender

Author: tamizhvendan

clojure/wheel/resources/config.edn

@@ -5,4 +5,5 @@
    :password           #or [#env "WHEEL_APP_DB_PASSWORD" "postgres"]
    :database-name      #or [#env "WHEEL_APP_DB_NAME" "wheel"]
    :server-name        #or [#env "WHEEL_APP_DB_SERVER" "localhost"]
-   :port-number        #or [#env "WHEEL_APP_DB_PORT" 5432]}}}
+   :port-number        #or [#env "WHEEL_APP_DB_PORT" 5432]}
+  :log {:slack {:webhook-url #env "WHEEL_APP_LOG_SLACK_WEBHOOK_URL"}}}}

clojure/wheel/src/wheel/infra/config.clj

@@ -12,6 +12,9 @@
 (defn database []
   (get-in root [:app :database]))
 
+(defn slack-log-webhook-url []
+  (get-in root [:app :log :slack :webhook-url]))
+
 (comment
   (mount/start)
   (database)

clojure/wheel/src/wheel/infra/log.clj

@@ -3,15 +3,17 @@
             [cheshire.core :as json]
             [clojure.spec.alpha :as s]
             [wheel.middleware.event :as event]
-            [wheel.infra.log-appender.database :as database]))
+            [wheel.infra.log-appender.database :as database]
+            [wheel.infra.log-appender.slack :as slack]))
 
 (defn- json-output [{:keys [msg_]}]
   (let [event (read-string (force msg_))]
     (json/generate-string event)))
 
 (defn init []
   (timbre/merge-config! {:output-fn json-output
-                         :appenders {:database database/appender}}))
+                         :appenders {:database database/appender
+                                     :slack slack/appender}}))
 
 (defn write! [{:keys [level]
                :as event}]
@@ -35,10 +37,10 @@
   (write! {:level :info :name :foo})
   (s/check-asserts false)
   (s/assert ::event/event {:level :info :name :foo})
-  (write! {:name :deranging/succeeded
+  (write! {:name :ranging/failed
            :type :domain
-           :level :info
-           :channel-id "UB"
+           :level :error
+           :channel-id "UA"
            :timestamp "2019-10-04T15:56+05:30"
            :id (java.util.UUID/randomUUID)
            :channel-name :tata-cliq})

clojure/wheel/src/wheel/infra/log_appender/slack.clj

@@ -0,0 +1,41 @@
+(ns wheel.infra.log-appender.slack
+  (:require [wheel.slack.webhook :as slack]
+            [wheel.infra.config :as config]))
+
+(defn- event->text [{event-name :name}]
+  (str (namespace event-name) " " (name event-name)))
+
+(defn- event->attachment [{:keys [id channel-id channel-name]}]
+  {:color :danger
+   :fields [{:title "Channel Name"
+             :value channel-name
+             :short true}
+            {:title "Channel Id"
+             :value channel-id
+             :short true}
+            {:title "Event Id"
+             :value id}]})
+
+(defn- send-to-slack [{:keys [msg_]}]
+  (let [event (read-string (force msg_))]
+    (when (= :domain (:type event))
+      (let [text (event->text event)
+            attachment (event->attachment event)]
+        (slack/post-message! (config/slack-log-webhook-url) text [attachment])))))
+
+(event->attachment {:name :ranging/failed, 
+  :type :domain, 
+  :level :error, 
+  :channel-id "UA", 
+  :timestamp "2019-10-04T15:56+05:30", 
+  :id #uuid "5040f252-5ff4-4e44-ab9c-72275a5a40ba", 
+  :channel-name :tata-cliq})
+
+(def appender {:enabled? true
+               :output-fn :inherit
+               :async? true
+               :min-level :error
+               :fn send-to-slack})
+
+(comment
+  (event->text {:name :ranging/failed}))