Vanflow: Duplicate message delivery per distinct router path

[c-kruse]

As discussed in the Skupper Team g chat, I am observing repeated delivery of vanflow messages. This was uncovered by an unrelated skupper collector bug. Thanks for following along @ted-ross! I suspect this issue is in the router, but I didn't know where to start trying to reproduce it without the control plane.

To reproduce:

• Set up Skupper version 1.5.1 running in three namespaces a, b and c and link all three.

skupper token create --namespace a --uses 2 token-a.yaml

skupper link create --namespace b token-a.yaml
skupper token create --namespace b token-b.yaml

skupper link create --namespace c token-a.yaml
skupper link create --namespace c token-b.yaml

• Deploy this rough draft vanflow logging utility to each namespace to tail the logs. source.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: vanflow-logging
  labels:
    app: vanflow-logging
spec:
  replicas: 1
  selector:
    matchLabels:
      app: vanflow-logging
  template:
    metadata:
      labels:
        app: vanflow-logging
    spec:
      containers:
      - image: quay.io/ckruse/vanflow-tool:1.0-alpha3
        imagePullPolicy: Always
        name: main
        securityContext:
          runAsNonRoot: true
        volumeMounts:
        - mountPath: /etc/messaging/
          name: skupper-local-client
        args:
        - '-messaging-config=/etc/messaging/connect.json'
        - '-enable-flow-records=false'
        - 'log'
      volumes:
      - name: skupper-local-client
        secret:
          defaultMode: 420
          secretName: skupper-local-client

• Tail the logs of the vanflow logging utilities as you interact with the cluster. Messages originating in the A namespace are logged once from the A namespace but twice from the B and C namespaces.

[jiridanek]

This is probably a workaround for this?

• Fixes phantom process records observed in the console UI skupper#1341

[c-kruse]

This is probably a workaround for this?

* [Fixes phantom process records observed in the console UI skupper#1341](https://github.com/skupperproject/skupper/pull/1341)

They are related @jiridanek - but I'd hesitate to call either a workaround. The flow collector should be idempotent (fix in skupper/pull/1341), and from what I understand vanflow messages should be delivered only once to each consumer with some reliability regardless of van topology (the topic brought up in this issue.)

[Karen-Schoener]

Hi, I'm interested in investigating this ticket. If there's any concern / issue with me investigating this ticket, please do not hesitate to let me know. Thanks, Karen