Motivation

Currently we were recording operation name & code, or path for KV and HTTP operations respectively. According to the Extended Observability RFC, the db.operation metric field should have the same value as outer span names:

“db.operation”: Same as the “outer span names” - for example “get”, “get_and_lock” etc.

Changes

• Add an observaility_identifier static field to all requests, with the operation name specified in the RFC's outer span name table.
• Use that field to populate db.operation in metrics. (That field should also be used for the outer spans, will be done under a separate ticket)
• Fix bug where all HTTP operations were recorded with db.couchbase.service = "kv"
• Add tests for HTTP operation metrics