Error: runtime error: invalid memory address or nil pointer dereference (3.3.8)

[Siebjee]

Summary

When a valueFrom is used in a workflow parameter (arguments.parameters) it produces a:

Error: runtime error: invalid memory address or nil pointer dereference

What version are you running?

3.3.8

Diagnostics

Paste the smallest workflow that reproduces the bug. We must be able to run the workflow.

apiVersion: v1
kind: Secret
type: Opaque
metadata:
  name: my-secret
data:
  test: changeme

---
# The coinflip example combines the use of a script result,
# along with conditionals, to take a dynamic path in the
# workflow. In this example, depending on the result of the
# first step, 'flip-coin', the template will either run the
# 'heads' step or the 'tails' step.
apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  name: test-workflow-parameters-1
  annotations:
    workflows.argoproj.io/description: |
      This is an example of coin flip defined as a sequence of conditional steps.
      You can also run it in Python: https://couler-proj.github.io/couler/examples/#coin-flip
spec:
  entrypoint: coinflip
  arguments:
    parameters:
    - name: foobar
      valueFrom:
        secretKeyRef:
          name: my-secret
          key: test

  templates:
  - name: coinflip
    steps:
    - - name: flip-coin
        template: flip-coin
    - - name: heads
        template: heads
        when: "{{steps.flip-coin.outputs.result}} == heads"
      - name: tails
        template: tails
        when: "{{steps.flip-coin.outputs.result}} == tails"

  - name: flip-coin
    script:
      image: python:alpine3.6
      command: [python]
      source: |
        import random
        result = "heads" if random.randint(0,1) == 0 else "tails"
        print(result)
  - name: heads
    container:
      image: alpine:3.6
      command: [sh, -c]
      args: ["echo \"it was heads\""]

  - name: tails
    container:
      image: alpine:3.6
      command: [sh, -c]
      args: ["echo \"it was tails\""]

# Logs from the workflow controller:
kubectl logs -n argo deploy/workflow-controller | grep ${workflow} 

time="2022-08-01T12:12:03.772Z" level=info msg="Processing workflow" namespace=siebren workflow=test-workflow-parameters-1
time="2022-08-01T12:12:03.774Z" level=error msg="Recovered from panic" namespace=siebren r="runtime error: invalid memory address or nil pointer dereference" stack="goroutine 302 [running]:\nruntime/debug.Stack()\n\t/usr/local/go/src/runtime/debug/stack.go:24 +0x65\ngithub.com/argoproj/argo-workflows/v3/workflow/controller.(*wfOperationCtx).operate.func2()\n\t/go/src/github.com/argoproj/argo-workflows/workflow/controller/operator.go:194 +0xd4\npanic({0x1ce07c0, 0x33713e0})\n\t/usr/local/go/src/runtime/panic.go:1047 +0x266\ngithub.com/argoproj/argo-workflows/v3/workflow/controller.(*wfOperationCtx).setGlobalParameters(0xc001362d80, {{0xc000371ec0, 0x1, 0x1}, {0x0, 0x0, 0x0}})\n\t/go/src/github.com/argoproj/argo-workflows/workflow/controller/operator.go:571 +0xf22\ngithub.com/argoproj/argo-workflows/v3/workflow/controller.(*wfOperationCtx).setExecWorkflow(0xc001362d80, {0x22b0668, 0xc000058018})\n\t/go/src/github.com/argoproj/argo-workflows/workflow/controller/operator.go:3527 +0x726\ngithub.com/argoproj/argo-workflows/v3/workflow/controller.(*wfOperationCtx).operate(0xc001362d80, {0x22b0668, 0xc000058018})\n\t/go/src/github.com/argoproj/argo-workflows/workflow/controller/operator.go:208 +0x209\ngithub.com/argoproj/argo-workflows/v3/workflow/controller.(*WorkflowController).processNextItem(0xc00008dc00, {0x22b0668, 0xc000058018})\n\t/go/src/github.com/argoproj/argo-workflows/workflow/controller/controller.go:756 +0x8ee\ngithub.com/argoproj/argo-workflows/v3/workflow/controller.(*WorkflowController).runWorker(0x0)\n\t/go/src/github.com/argoproj/argo-workflows/workflow/controller/controller.go:678 +0x9e\nk8s.io/apimachinery/pkg/util/wait.BackoffUntil.func1(0x7f6812210978)\n\t/go/pkg/mod/k8s.io/[email protected]/pkg/util/wait/wait.go:155 +0x67\nk8s.io/apimachinery/pkg/util/wait.BackoffUntil(0x0, {0x226dbe0, 0xc003340a50}, 0x1, 0xc00043b4a0)\n\t/go/pkg/mod/k8s.io/[email protected]/pkg/util/wait/wait.go:156 +0xb6\nk8s.io/apimachinery/pkg/util/wait.JitterUntil(0x0, 0x3b9aca00, 0x0, 0x0, 0x0)\n\t/go/pkg/mod/k8s.io/[email protected]/pkg/util/wait/wait.go:133 +0x89\nk8s.io/apimachinery/pkg/util/wait.Until(0x0, 0x0, 0x0)\n\t/go/pkg/mod/k8s.io/[email protected]/pkg/util/wait/wait.go:90 +0x25\ncreated by github.com/argoproj/argo-workflows/v3/workflow/controller.(*WorkflowController).Run\n\t/go/src/github.com/argoproj/argo-workflows/workflow/controller/controller.go:294 +0x1a6c\n" workflow=test-workflow-parameters-1
time="2022-08-01T12:12:03.774Z" level=info msg="Updated phase  -> Error" namespace=siebren workflow=test-workflow-parameters-1
time="2022-08-01T12:12:03.774Z" level=info msg="Updated message  -> runtime error: invalid memory address or nil pointer dereference" namespace=siebren workflow=test-workflow-parameters-1
time="2022-08-01T12:12:03.774Z" level=info msg="Marking workflow completed" namespace=siebren workflow=test-workflow-parameters-1
time="2022-08-01T12:12:03.774Z" level=info msg="Checking daemoned children of " namespace=siebren workflow=test-workflow-parameters-1
time="2022-08-01T12:12:03.780Z" level=info msg="cleaning up pod" action=deletePod key=siebren/test-workflow-parameters-1-1340600742-agent/deletePod
time="2022-08-01T12:12:03.788Z" level=info msg="Workflow update successful" namespace=siebren phase=Error resourceVersion=164853863 workflow=test-workflow-parameters-1
time="2022-08-01T12:12:03.789Z" level=info msg="Queueing Error workflow siebren/test-workflow-parameters-1 for delete in 24h0m0s due to TTL"

---

Message from the maintainers:

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[smile-luobin]

secretKeyRef is unsupported in valueFrom.

arguments:

    parameters:
    - name: foobar
      valueFrom:
        secretKeyRef:
          name: my-secret
          key: test

will be Unmarshaled as:

    parameters:
    - name: foobar
      valueFrom: {}

there is no validation if valueFrom=={} in func validateArgumentsValues:

argo-workflows/workflow/validate/validate.go

Line 754 in 06b0a8c

if param.ValueFrom == nil && param.Value == nil {

[Siebjee]

But shouldn't the error be more explanatory :).

I didn't submit this issue because it's unsupported, but the error is not clear enough that it isn't supported. In fact it throws a "nil pointer". Which is bad :).

[smile-luobin]

@Siebjee agree with you.

maybe we can do validation in func validateArgumentsValues argo-workflows/workflow/validate/validate.go, and return a more explanatory error if valueFrom=={}.

[sarabala1979]

@smile-luobin Do you like to submit the PR?

[alexec]

To fix this, modify this block of code

From:

argo-workflows/workflow/controller/operator.go

Line 559 in 621b0d1

for _, param := range executionParameters.Parameters {

To:

	for _, param := range executionParameters.Parameters {
		if param.ValueFrom != nil && param.ValueFrom.ConfigMapKeyRef != nil {
			cmValue, err := common.GetConfigMapValue(woc.controller.configMapInformer, woc.wf.ObjectMeta.Namespace, param.ValueFrom.ConfigMapKeyRef.Name, param.ValueFrom.ConfigMapKeyRef.Key)
			if err != nil {
				return fmt.Errorf("failed to set global parameter %s from configmap with name %s and key %s: %w",
					param.Name, param.ValueFrom.ConfigMapKeyRef.Name, param.ValueFrom.ConfigMapKeyRef.Key, err)
			}
			woc.globalParams["workflow.parameters."+param.Name] = cmValue
		} else if param.Value != nil {
			woc.globalParams["workflow.parameters."+param.Name] = param.Value.String()
		} else {
			return fmt.Errorf("either value or valueFrom must be specified in order to set global parameter %s", 
                }
	}

This is a really easy fix. Would someone like to volunteer?