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Workflow Chain Transitions

In this section

This section will help you:

  • Know what Transition Strategies are and how to use them.

  • Know what Transition Rules are and how to use them.

  • Know the difference between virtual and non-virtual transitions.

Key Terms

Table 16. 

Term

Definition

Transition Strategy

A logic statement that states which Entities will transition to the next Workflow in a Workflow Chain.

Transition Rule

A logic statement that determines when Entities will transition to the next Workflow in a Workflow Chain.



What is the Transition Editor?

The Transition Editor is the modal used to define how Entities move through a Workflow Chain. To access the Transition Editor, either click on an arrow that joins two existing nodes or select the blue dot at the top of a node and drag the arrow to an existing node to form a new connection.

The Transition Editor has two key components: strategy and rule. Think of the strategy as the “who” and the rule as the “when” - which Entities will be transitioned and when will they be transitioned.

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How to use Transition Rules

Rules are encoded in Python. Two (2) of the most common rules are:

  • {{ True }} - transitions all Entities set by the strategy when the End User completes the upstream Workflow.

  • {{ is_node_selected() }} - transitions the Entities set by the strategy to the Workflow(s) selected in the Next Step field of the upstream Workflow. This field can have a default value dependent on the data collected and supports the dynamic nature of branching Workflow Chains.

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Next Step must be a picklist with options set by L7|ESP Expression {{ next_node_choices() }} for this rule to work. If more than one Workflow can be selected, make this field a multi-select picklist.

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Note

{{ is_node_selected() }} and {{ next_node_choices() }} are covered in more detail here and in Section 6.2.5 of the User Documentation.

Additional Examples

  • Evaluating an Entity value:

{{ entity_value('Field Name') == 'Value' }}

  • Evaluating a boolean (checkbox) value:

{{ str(cell('Field ID')).lower() == 'true' }}

  • Evaluating a picklist value:

{{ cell('Field ID', 'Protocol ID') == 'Value' }}

  • Evaluating more than one (1) picklist value:

{{ cell('Field ID', 'Protocol ID') in ['Value 1', 'Value 2'] }}

Note

By default, only {{ is_node_selected() }} excludes failed Entities in the transition, unless paired with the Resubmit transition strategy.

To exclude failed Entities, include and not sample['failed'] in all other rules.

How to use Transition Strategies

L7|ESP has three out-of-box strategies:

  1. Identity – transitions the final Sample Set in the upstream Workflow.

  2. Resubmit – transitions the starting Sample Set for the selected Workflow.

  3. Createsample – creates Samples from the selected Sample Type as children of the final Sample Set in the upstream Workflow. This transition strategy is not as flexible as a Sample Protocol, and is typically used for in-flight Sample creation, as Workflows cannot begin with a Sample Protocol.

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Note

Developers can create custom Transition Strategies, which is a topic of the Developer MasterClass.

Section 7.2.3 of the User Documentation provides an example of a custom Transition Strategy.

How to use Virtual and Non-Virtual Transitions

The “This is a virtual transition” checkbox converts the solid grey arrow to an orange dashed arrow. There is no functional difference between a virtual and non-virtual transition. Virtual transitions are typically seen as optional, whereas non-virtual transitions serve as the consistent path for Entities to take across the Workflow Chain.

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