Unify metrics for object stores

[tomwilkie]

We're missing any metrics for the azure client[1], and we have different metrics for S3[2] and GCS[3]. We should rationalise this into some sort of middleware for the object store interface that makes this more consistent.

[1] https://github.com/cortexproject/cortex/blob/master/pkg/chunk/azure/blob_storage_client.go
[2] https://github.com/cortexproject/cortex/blob/master/pkg/chunk/aws/s3_storage_client.go#L26
[3]

cortex/pkg/chunk/gcp/instrumentation.go

Line 53 in 996cb83

func gcsInstrumentation(ctx context.Context, scope string) (option.ClientOption, error) {

[bboreham]

Less likely we will do this now that Blocks are preferred to Chunks.

[stale]

This issue has been automatically marked as stale because it has not had any activity in the past 60 days. It will be closed in 15 days if no further activity occurs. Thank you for your contributions.