Structure output and document error conditions

[heffergm]

Logging output should be structured and error conditions documented. In production, logs will be streamed to Cloudwatch Logs, where filters will be built to pick up the structured data and turn it into Cloudwatch metrics which can then be used to trigger alarm conditions.

http://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/FilterAndPatternSyntax.html