Added simple yubikey state module

bumblebee/modules/yubikey.py

@@ -0,0 +1,33 @@
+# pylint: disable=C0111,R0903
+
+"""Shows yubikey information
+
+Requires: https://github.com/Yubico/python-yubico
+
+The output indicates that a YubiKey is not connected or it displays
+the corresponding serial number.
+
+"""
+
+import yubico
+
+import bumblebee.input
+import bumblebee.output
+import bumblebee.engine
+
+class Module(bumblebee.engine.Module):
+    def __init__(self, engine, config):
+        super(Module, self).__init__(engine, config,
+                                     bumblebee.output.Widget(full_text=self.keystate))
+        self._keystate = "No YubiKey"
+
+    def keystate(self, widget):
+        return self._keystate
+
+    def update(self, widget):
+        try:
+            self._keystate = "YubiKey: " + str(yubico.find_yubikey(debug=False).serial())
+        except yubico.yubico_exception.YubicoError:
+            self._keystate = "No YubiKey"
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4