"Cassandra" Instrumentation Should Include Missing Destination Context

[astorm]

Is your feature request related to a problem? Please describe.

Similar to this MongoDB ticket, it looks like our Cassandra Instrumentation does not set a destination context on its spans. This means Cassandra will be absent from the Service Map.

We should consider adding destination context to the Cassandra spans.

[trentm]

Notes for if/when adding cassandra-driver destination context:

• A successful cassandra-driver query will return a ResultSet from which queriedHost can be used for dest context.

  ResultSet {
      info: {
          queriedHost: '127.0.0.1:9042',
          triedHosts: [Object],
          speculativeExecutions: 0,
          achievedConsistency: 10,
          traceId: undefined,
          warnings: undefined,
          customPayload: undefined,
          isSchemaInAgreement: true
      },
          rows: undefined,
          rowLength: undefined,
          columns: null,
          pageState: null,
          nextPage: undefined,
          nextPageAsync: undefined
      }
  }
  

• This requires some light refactoring to cleaning get that ResultSet for callback and promise forms.
• This needs some testing for whether we get that 'queriedHost' for failed queries as well.
• An alternative is to use the ClientOptions configured contactPoints (https://docs.datastax.com/en/developer/nodejs-driver/4.6/api/type.ClientOptions/). If so, which one? Also we need to normalize to add the default port? queriedHost is preferred, IMO, but might not always be available.
• Also this is a good time to add captureError for query/connect errors.
• Also span.setOutcome based on error-or-not