AWS Cloudwatch has an api which allows fetching metric statistics:
I have been able to find the REST definition for azure which appears to have similar functionality:
but I can't find the Go implementation. azure-sdk-for-go has a lot of code in it, but I can't find the code for listing metric values.
Some more details: I am trying to get status code statistics for an application gateway.
The operations you're mentioning can be found in the package:
github.com/Azure/azure-sdk-for-go/services/monitor/mgmt/2018-03-01/insights
In general though, if you're ever able to find a link to the REST documentation, the Azure SDK for Go can be searched for the URL of the operation. For yours in particular, I searched "/providers/micorosoft.insights/metrics" and was able to zero in on the operation.