logstash/logstash — pull request #638 by hduregger (2013-09-13 09:00:45+00:00)
Title:  Add more options to specify AWS credentials

* Allow not to specify the access and secret keys explicitly in order to
fallback to environment variable settings or EC2 instance metadata.
* If logstash is run on Amazon EC2 instances, the use of the instance
metadata allows easier maintenance and better security because the
access keys are not explicitly listed in the configuration and
managed by AWS itself.