Merge pull request #29 from sendle/master

Allow configuration of redis using {:system, envvar}

README.md

@@ -512,6 +512,9 @@ config :fun_with_flags, :redis,
 
 # a URL string can be used instead
 config :fun_with_flags, :redis, "redis://locahost:6379/0"
+
+# a {:system, name} tuple can be used to read from the environment
+config :fun_with_flags, :redis, {:system, "REDIS_URL"}
 ```
 
 ### Persistence Adapters

lib/fun_with_flags/config.ex

@@ -27,6 +27,8 @@ defmodule FunWithFlags.Config do
         uri
       opts when is_list(opts) ->
         Keyword.merge(@default_redis_config, opts)
+      {:system, var} when is_binary(var) ->
+        System.get_env(var)
     end
   end
 

test/fun_with_flags/config_test.exs

@@ -28,6 +28,12 @@ defmodule FunWithFlags.ConfigTest do
     assert            2000 == Config.redis_config[:port]
     assert              42 == Config.redis_config[:database]
 
+    # Whe configured with a {:system, env} tuple it looks up the value in the env
+    System.put_env("123_TEST_REDIS_URL", url)
+    configure_redis_with({:system, "123_TEST_REDIS_URL"})
+    assert url == Config.redis_config
+    System.delete_env("123_TEST_REDIS_URL")
+
     # cleanup
     configure_redis_with(defaults)
   end