Add new table: gcp_instance_metadata

[mwarkentin]

Feature request

What new feature do you want?

I would like a table for querying instance metadata of my VMs on GCP, similar to how it can be done for:

• AWS
• Azure
• Yandex Cloud

How is this new feature useful?

Being able to query things like if OS Login is enabled, project ID, zone, service account email, etc. for my instances.

How can this be implemented?

I assume this would be similar to the way it's implemented for other providers.

Docs

Example curl requests to the metadata endpoint when shelled into the VM:

curl "http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/scopes" -H "Metadata-Flavor: Google"

curl "http://metadata.google.internal/computeMetadata/v1/project/attributes/?recursive=true&alt=text" \
    -H "Metadata-Flavor: Google"

curl "http://metadata.google.internal/computeMetadata/v1/instance/attributes/?recursive=true&alt=text" \
    -H "Metadata-Flavor: Google"