[CLOUD-319] Make mixlib-log an optional dependency

This change makes mixlib-log an optional dependency. When it's available
in the LOAD_PATH it will be used by default, otherwise, all logging will
will be forwarded to a null logger that does nothing. This is useful for
cases where small utilities can consume mixlib-authentication and not
have to pull in additional gems.

Signed-off-by: Ryan Cragun <me@ryan.ec>

1 files changed, 12 insertions, 4 deletions

diff --git a/lib/mixlib/authentication.rb b/lib/mixlib/authentication.rb
index 443512e..b27e06e 100644
--- a/lib/mixlib/authentication.rb
+++ b/lib/mixlib/authentication.rb
@@ -16,12 +16,13 @@
 # limitations under the License.
 #
 
-require "mixlib/log"
-
 module Mixlib
   module Authentication
     DEFAULT_SERVER_API_VERSION = "0"
 
+    attr_accessor :logger
+    module_function :logger, :logger=
+
     class AuthenticationError < StandardError
     end
 
@@ -29,10 +30,17 @@ module Mixlib
     end
 
     class Log
-      extend Mixlib::Log
     end
 
-    Log.level = :error
+    begin
+      require "mixlib/log"
+      Mixlib::Authentication::Log.extend(Mixlib::Log)
+    rescue LoadError
+      require "mixlib/authentication/null_logger"
+      Mixlib::Authentication::Log.extend(Mixlib::Authentication::NullLogger)
+    end
 
+    Mixlib::Authentication.logger = Mixlib::Authentication::Log
+    Mixlib::Authentication.logger.level = :error
   end
 end