How To Debug

To enable debug logs in a Vertex Pod, set environment variable NUMAFLOW_DEBUG to true for the Vertex. For example:

apiVersion: numaflow.numaproj.io/v1alpha1
kind: Pipeline
metadata:
  name: simple-pipeline
spec:
  vertices:
    - name: in
      source:
        generator:
          rpu: 100
          duration: 1s
    - name: p1
      udf:
        container:
          image: quay.io/numaio/numaflow-go/map-cat:stable # A UDF which simply cats the message
          imagePullPolicy: Always
      containerTemplate:
        env:
          - name: NUMAFLOW_DEBUG
            value: !!str "true"
    - name: out
      sink:
        log: {}
  edges:
    - from: in
      to: p1
    - from: p1
      to: out

To enable debug logs in the daemon pod, set environment variable NUMAFLOW_DEBUG to true for the daemon pod. For example:

apiVersion: numaflow.numaproj.io/v1alpha1
kind: Pipeline
metadata:
  name: simple-pipeline
spec:
  templates:
    daemon:
      containerTemplate:
        env:
          - name: NUMAFLOW_DEBUG
            value: !!str "true"

Profiling

If your pipeline is running with NUMAFLOW_DEBUG then pprof is enabled in the Vertex Pod. You can also enable just pprof by setting NUMAFLOW_PPROF to true.

For example, run the commands like below to profile memory usage for a Vertex Pod, a web page displaying the memory information will be automatically opened.

# Port-forward
kubectl port-forward simple-pipeline-p1-0-7jzbn 2469

go tool pprof -http localhost:8081 https+insecure://localhost:2469/debug/pprof/heap

Tracing is also available with commands below.

# Add optional "&seconds=n" to specify the duration.
curl -skq https://localhost:2469/debug/pprof/trace?debug=1 -o trace.out

go tool trace -http localhost:8082 trace.out

Debug Inside the Container

When doing local development using command lines such as make start, or make image, the built numaflow docker image is based on alpine, which allows you to execute into the container for debugging with kubectl exec -it {pod-name} -c {container-name} -- sh.

This is not allowed when running pipelines with official released images, as they are based on scratch.