Workflow Variable Rules (`VAR`)¶

The code VAR identifies potential issues with workflow variables, including syntax errors, misused functions, and other related problems.

Known Limitations

Currently, Tugboat supports only simple tags, and does not support expression tags.

This means:

{{ inputs.parameters.simple }} can be checked
{{= inputs.parameters.expression }} will be ignored

We are planning to add support for expression tags in an upcoming release.

VAR101 Syntax error¶

This error occurs when a workflow variable fails to parse due to a syntax error.

Note that most parsers report syntax errors as soon as they encounter the first issue. This means the error message might not always indicate the exact location of the problem, but it provides a useful starting point for debugging.

VAR102 Incorrect template tag format¶

This error occurs when a reference uses expression tag syntax inside a simple template tag.

Argo Workflows supports two types of template tags:

Simple tags: {{ inputs.parameters.foo }}
Expression tags: {{= inputs.parameters.foo }}

The syntax for referencing values differs between these two formats. Simple tags use dot notation only (e.g., inputs.parameters.foo), while expression tags use expr-lang syntax, which supports both dot notation and bracket notation for member access (e.g., inputs.parameters['foo'] or inputs["parameters"]["foo"]).

This error is reported when expression tag syntax is mistakenly used inside a simple tag.

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: test-
spec:
  entrypoint: whalesay
  templates:
    - name: whalesay
      inputs:
        parameters:
          - name: message
      container:
        image: docker/whalesay:latest
        args: ["{{ inputs.parameters['message'] }}"]

In the example above, inputs.parameters['message'] uses bracket notation, which is valid in expression tags but not in simple tags. The correct format for a simple tag is {{ inputs.parameters.message }}.

VAR201 Unknown Argo workflow variable reference¶

This error occurs when a reference is not recognized as a valid Argo workflow variable in the current context.

Tugboat validates references against a list of known Argo workflow variables based on the template type and defined inputs/outputs. If a reference cannot be matched to any known variable, this error is reported.

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: test-
spec:
  entrypoint: main
  templates:
    - name: main
      inputs:
        parameters:
          - name: message
      steps:
        - - name: step-1
            template: produce
            arguments:
              parameters:
                - name: msg
                  value: "{{ inputs.parameters.msg }}"
        - - name: step-2
            template: consume
            arguments:
              parameters:
                - name: msg
                  value: "{{ steps.step-1.outputs.parameters.massage }}"

In the example above, inputs.parameters.msg is reported because the defined parameter is named message, not msg.

When possible, Tugboat will suggest the closest matching variable name as a fix.

Note

Tugboat can only validate references within the same manifest. References to step outputs (e.g., steps.step-1.outputs.parameters.message) cannot be fully validated because the output is defined by the referenced template, which may be a WorkflowTemplate defined elsewhere.

VAR202 Not an Argo workflow variable reference¶

This warning occurs when a template tag contains a single identifier that does not match any known Argo workflow variable pattern.

Argo workflow variables typically have a dotted format like inputs.parameters.name or workflow.name. When a tag contains only a simple variable name (e.g., {{ foo }}), it is unlikely to be an Argo variable.

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: test-
spec:
  entrypoint: whalesay
  templates:
    - name: whalesay
      container:
        image: docker/whalesay:latest
        args: ["{{ message }}"]

In the example above, {{ message }} is flagged because message is not a valid Argo workflow variable.

This warning is commonly triggered when:

The manifest uses another templating engine (e.g., Jinja2, Helm) that shares the {{ }} syntax
There is a typo or incomplete variable reference

If the tag is intended for another templating engine, you can suppress this warning by adding a # noqa: VAR202 comment. See Ignoring Violations for more information on suppressing warnings.