Description

Replaces PR #2262 .
Internal version of this functionality had diverged sufficiently from original PR that it is cleaner to start afresh

Requires a role with the ListMetrics and GetMetricData capabilities.
Role can be supplied using either the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables or by attaching it to the EC2 instance on which bosun runs.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How has this been tested?

• CloudWatch query functionality had good unit test coverage
• Has been used in production in Skyscanner for several years

Checklist:

• This contribution follows the project's code of conduct
• This contribution follows the project's contributing guidelines
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules