LogName should be more useful in the collector exporter.

[dashpole]

Ideally, if a user sets service.name, we should use that. Maybe fall back to faas.name. All logs being written to a single log name is suboptimal.

cc @jsuereth

[aabmass]

I think what we decided to implement is:

• If gcp.log_name attribute exists
  • If its value matches an Origin rule, e.g. /projects/{project_name}/logs/{log_name} use it exactly. log_name must be url-encoded.
  • Otherwise use its url-encoded value in a synthesized url, e.g. /projects/{default_project_id}/logs/{url_encoded_log_name}. The URL is chosen by selecting an owner using the Origin lookup rules.
  • In both cases, the full log name string must be less than 512 characters, or fallback
• If service.name attribute exists (and gcp.log_name does not), this will be used as a log name:
  /{origin URL}/logs/{service.name}
• Otherwise this will be /{origin URL}/logs/otelcollector or similar