Statistics of opal-clients

[hongbo-miao]

EDIT: created the feature request ticket at https://github.com/authorizon/opal/issues/155

---

Hi OPAL team, assume we have

• Multiple pods in a Kubernetes cluster
• Each/some pods has a main container and a sidecar container with opal-client inside
• Each/some pods has multiple replicas
• Each opal-client in the sidecar container can subscribe one or more topics

Is there a way such as letting opal-servers to return some statistics such as

• the total number of OPAL clients
• the number of OPAL clients per application/pod (each application/pod can have multiple replicas. All subscribe to same one or multiple topics)
• the number of OPAL clients per topic (This might not be really useful as one opal-client can subscribe one or multiple topics)

Thanks!

[asafc]

We currently do not have such feature, let's spec it out together.
We would also appreciate pull requests if you want to try and tackle it yourself ;)

cc @orweis @obsd can you take it from here?

[orweis]

Hi @hongbo-miao :)
This should actually be very easy to achieve through OPAL's event driven nature (actually one of the main reasons we chose this architecture )

We can essentially have a new component (as part of an OPAL server, or separate) subscribing to the OPAL channel (via ALL_TOPICS), similar to what the OPAL-Clients do.

And produce statistics about all of the metrics you listed and more...
That said, the the K8S / pod information or other meta data would need to be correlated - either based on additional meta data, or the topic information.