Describe the feature request

The Stackdriver telemetry v2 adapter should send logging output equivalent to what was being sent with the Mixer adapter, as much as possible.

Describe alternatives you've considered

N/A

Additional context

From looking at https://github.com/istio/proxy/blob/master/extensions/stackdriver/log/logger.cc#L79 I believe that the following expected logging need to be added:

• source_uid: source.uid | ""
• source_ip: source.ip | ip("0.0.0.0")
• source_app: source.labels["app"] | ""
• source_owner: source.owner | ""
• destination_uid: destination.uid | ""
• destination_app: destination.labels["app"] | ""
• destination_ip: destination.ip | ip("0.0.0.0")
• destination_owner: destination.owner | ""
• api_name: api.service | ""
• api_version: api.version | ""
• api_claims: request.auth.raw_claims | ""
• api_key: request.api_key | request.headers["x-api-key"] | ""
• method: request.method | ""
• url: request.path | ""
• response_code: response.code | 0
• response_size: response.size | 0
• request_size: request.size | 0
• request_id: request.headers["x-request-id"] | ""
• latency: response.duration | "0ms"
• user_agent: request.useragent | ""
• response_timestamp: response.time
• received_bytes: request.total_size | 0
• sent_bytes: response.total_size | 0
• referer: request.referer | ""

I understand that a handful of these are infeasible; that's okay, we don't need 100% coverage.