Detect service attributes for GCE instances.

[Tasty213]

The OpenTelemetry semantic conventions defines a number of attributes that be logical to set as resource attributes for GCE compute instances. Currently using these on an internal project but i appreciate their applicability might just be due to how our GCP setup works.

• service.instance.id The string ID of the service instance, this is the four characters at the end of a GCE VM Instance.
• service.namespace A string value having a meaning that helps to distinguish a group of services, in our case this is the project the VM is in.
• service.name Must be the same for all instances of horizontally scaled services, we've set this to the instance group name
• service.version The version string of the service API or implementation, and this is the instance template name each increment of which is a new version of the service.

This means that the combination of service namespace, service name and instance id is a globally unique identifier for that VM.

Service attributes spec

Quick demo of how these values could be acquired there's probably a better way to do this.

class ServiceResourceDetector(GoogleCloudResourceDetector):
    def detect(self) -> Resource:
        try:
            resources = super().detect()
        except NoGoogleResourcesFound:
            resources = Resource.create({})

        custom_resources = Resource.create(
            {
                ResourceAttributes.SERVICE_INSTANCE_ID: self.get_instance_id(),
                ResourceAttributes.SERVICE_NAME: self.get_service_name(),
                ResourceAttributes.SERVICE_NAMESPACE: self.get_project_id(),
            }
        )
        return resources.merge(custom_resources)

    @staticmethod
    def get_instance_id():
        return ServiceResourceDetector._get_host_name()[-4:]

    @staticmethod
    def get_service_name():
        return ServiceResourceDetector._get_host_name()[:-5]

    @staticmethod
    def _get_host_name():
        return socket.gethostname()

Essentially is GCE instance group setups widely standard enough that we can reliably use instance group/template/project to define the attributes?

[aabmass]

Sorry for the slow reply here

Essentially is GCE instance group setups widely standard enough that we can reliably use instance group/template/project to define the attributes?

If each VM is only running one process reporting telemetry, this could be a reasonable approach. I think it's pretty common for other users to have multiple applications running in one VM, which would cause conflicts. Ofc it also depends on you naming your VMs in such a way that service.name means something to your developers. I'm not sure if this would be widely applicable to other users.

Hope that answers your question.