Provide pod labels with metadata

[tharinduwijewardane]

Is your feature request related to a problem? Please describe.
We are unable to aggregate telemetry data using a ID we set as a pod label.

Describe the solution you'd like
Provide pod labels (as a string?) along with the existing metadata
Often a pod name is a generated string and the users track pods by setting labels. Therefore this is a useful feature to have.

Describe alternatives you've considered

Additional context

[tharinduwijewardane]

What is the feasibility of this? Can someone please point to the existing code where pod ids and pod names are extracted.

[aimichelle]

Hi @tharinduwijewardane ! The task isn't particularly difficult, but has a few moving parts. Happy to point you to the right places/work closely with you to push this through.

Here is the general flow of what happens to extract and make use of the pod labels:

1. Extracting the labels from pod info that we get from the K8s API. This all happens in the metadata service. The metadata service is responsible for taking the pod info and generating a K8sUpdate proto message which is sent to all of the PEMs. This is where the message is populated: https://github.com/pixie-io/pixie/blob/main/src/vizier/services/metadata/controllers/k8smeta/k8s_metadata_handler.go#L924 and here is where the proto message itself is defined: https://github.com/pixie-io/pixie/blob/main/src/shared/k8s/metadatapb/metadata.proto#L383
2. The PEMs receive the update, parse it, and store the pod data in-memory: https://github.com/pixie-io/pixie/blob/main/src/shared/metadata/metadata_state.cc#L157
3. A PxL function can be written to leverage the pod data in PxL. An example is here:

   pixie/src/carnot/funcs/metadata/metadata_ops.h

   Line 919 in eb81bd1

   class PodIDToPodStartTimeUDF : public ScalarUDF {

Feel free to reach out to me directly on Slack for more detailed questions as well.

[zasgar]

@tharinduwijewardane, This will be a great feature for us to have. Are you interested in contributing this? We can help out as needed.

[tharinduwijewardane]

@zasgar Yes. I had difficulties building pixie locally (asked them in pixienaut channel). Finally I could get it working with ubuntu 22.04. I am going to look into this now.

[tharinduwijewardane]

@aimichelle @zasgar I submitted a PR for this. Could you please review.