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While Task

The while task repeatedly executes a set of steps as long as specified conditions remain true. It is useful for polling, retry logic, or any scenario where the number of iterations is not known in advance.

While Task Structure​

Example of a While task step:

activities:
  - name: "PollForCompletion"
    description: "Poll an external system until the job completes."
    variables:
      - name: "jobComplete"
        value: "false"
    steps:
      - task: "while"
        name: "waitForJob"
        conditions:
          - expression: "[jobComplete] == 'false'"
        maxIterations: 50
        steps:
          - task: "Http/Get@1"
            name: checkStatus
            inputs:
              url: "{{apiUrl}}/jobs/{{jobId}}/status"
            outputs:
              - name: jobComplete
                mapping: "result.isComplete"

Attributes​

  • conditions (required) - A list of conditions that are evaluated before each iteration. The loop continues as long as all conditions evaluate to true. At least one condition must be specified.
  • steps (required) - The list of task steps to execute on each iteration. Must have at least one step.
  • maxIterations (optional) - The maximum number of iterations the While loop will execute. Defaults to 1000. If the loop reaches this limit, it stops and the workflow continues with the next step. This acts as a safety guard to prevent infinite loops from consuming excessive resources.
  • continueOnError (optional) - A boolean that controls whether the workflow should continue if an error occurs during an iteration. Defaults to false (the workflow stops on error).

Built-in Variables​

During execution, the While task exposes the following variable:

VariableTypeDescription
iterationintegerZero-based index of the current iteration. Removed after the loop completes.

Best Practices​

  • Always set maxIterations when you know an upper bound for your use case. The default of 1000 protects against infinite loops, but a tighter limit makes intent clearer and catches logic errors faster.
  • Update loop variables inside steps so the condition can eventually become false. A While loop whose condition never changes will run until maxIterations is reached.
  • Use continueOnError: true for retry patterns where occasional failures are expected and should not abort the entire workflow.