Implement monitored resource for logging client

[theacodes]

Log entries can have a monitored resource associated with them as of v2 of the logging API.

• entries.write documentation: https://cloud.google.com/logging/docs/reference/v2/rest/v2/entries/write
• MonitoredResource reference: https://cloud.google.com/logging/docs/reference/v2/rest/v2/MonitoredResource
• Existing tiny resource class in monitoring: https://github.com/GoogleCloudPlatform/google-cloud-python/blob/master/monitoring/google/cloud/monitoring/resource.py#L159

Essentially, the _BaseEntry class should be extend to accept a resource. Helper methods such as log_text and log_struct should likely be extended to accept the resource as well.

This'll need to work with http and gax.

[jaitaiwan]

We discovered this today in dev when moving from using the app log to request_log in google app engine. Is there any way to get the resource information per ProtobufEntry even without it being part of the _BaseEntry?

[theacodes]

@jaitaiwan not without using the gapic layer directly.

[duggelz]

Do we have documentation anywhere of the mapping from MonitoredResource type to list of labels used? Or perhaps we don't need it, we just copy whatever we find.

[theacodes]

Do we have documentation anywhere of the mapping from MonitoredResource type to list of labels used? Or perhaps we don't need it, we just copy whatever we find.

It's here: https://cloud.google.com/logging/docs/api/v2/resource-list

We don't need to include in the client library, as it'll very quickly get out of date. We just need to accept a string and let the backend do the validation.