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 template tags, and does not support expression template tags.

This means:

{{ inputs.parameters.foo }} can be checked

but {{= inputs.parameters.foo }} will be ignored

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

Rules

VAR001 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.

VAR002 Misused reference

A reference used in the manifest is not defined in the current context.

Tugboat checks the references used in the manifest against a list of references from the official documentation. If a reference used in the manifest is not found in the defined references, an error is reported.

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: test-
spec:
  entrypoint: whalesay
  templates:
    - name: whalesay
      inputs:
        artifacts:
          - name: message
            raw:
              data: Hello Tugboat!
      container:
        image: docker/whalesay:latest
        command: [cowsay]
        args: ["{{ inputs.artifacts.message }}"]

In the example above, inputs.artifacts.message is invalid because referencing artifacts in this field is not allowed.

Limited validation of step outputs

Tugboat can only validate references within the same manifest.

The outputs of a step are defined by the template it refers to. Tugboat cannot validate these outputs because their definitions are not included in the same manifest. This means Tugboat cannot verify references that point to the outputs of other steps.