Model selection

Click ‘Build a flow’, filter the list of candidate models, pick the ones which you want to include and click ‘Load models’.

trac build a flow screen with candidate model selection

On the next page you will see the selected models listed and have the option to perform three actions:

  1. Select an alternate (older) version of a selected model object

  2. Remove one of the selected models entirely

  3. Return to the model picker and add another model

trac flow builder showing selected models and version options

Configuring flow nodes

You can change how each model and dataset in the flow is represented in the user interface and in governance reports which you later export by changing Labels, Categories and Intermediates.

Labels and categories

Label is a reader-friendly version of the Key which is displayed in the UI and in governance reports.

Categories are used to group models and data on the pages from which you launch a job. They’re optional and are only useful if a flow has a very large number of inputs which can be meaningfully categorised to improve the UX when launching a job.

Intermediates

The ‘Save’ toggle on the list of Outputs allows you to change a node in the flow between Intermediate (grey) and Output data (blue). Intermediates are not outputted when the flow is run.

trac flow builder Save toggle for Intermediate and Output data nodes

Visualisation of the graph

At the bottom of the page is a representation of the flow, highlighting model, inputs, outputs and intermediate.

If you selected models with common Keys, you should see a diagram like this…

trac flow graph showing models connected by common keys

If you selected models with no common Keys, it might look more like this…

trac flow graph showing models with no common keys

Both are technically correct but the first pattern is more commonly what people aim for.

You can edit the default wiring using the Advanced options drop-down.

The rewiring tool allows you to replace Input data (orange) with an internal link, by manually mapping the Key of a model’s output to the Key of another model’s input. Manual rewiring works if the data sets have different Keys but their schemas are consistent.

trac flow rewiring tool for replacing an input with an internal link

The dustbin allows you to remove a rewired link and return to the default flow.

Saving the flow

Once you are happy with the flow, provide the general attributes and click ‘Upload’.

If the upload is successful you can find the flow via (Search Page) and use it to (Run a flow).

trac save flow screen with general attributes and Upload button

The most common reasons for being unable to save a new flow are missing name and description fields.

trac flow save error for missing name and description fields