Ref: https://www.elastic.co/logstash/

Currently, when a module fails to send a new log it will raise an error - This can cause unintended crashes - Should be made so it doesn't cause hard crashes

In the dict self.moudles, all keys are lowercase，eg:

• self.modules["stdout"] (key is "stdout")
• self.modules["elasticsearch"] (key is "elasticsearch")
  but at line 101 of file loghandler/app.py, the value of output["type"] maybe "STDOUT", "ElasticSearch"。Therefore, the logic underblow is wrong：
  output = [
  output for output in self.config["outputs"] if output["type"] == key
  ][0]

The correct logic should be：
output = [
output for output in self.config["outputs"] if output["type"].lower() == key
][0]

Unused import and var should be removed

Ref: https://sentry.io/welcome/