Variables and expressions in CRMint

CRMint can use dynamically generated parameters throughout a project or pipeline. This allows you to :

• Define once, use many times: A project ID or table name for example, can be used in many places throughout your pipeline(s). Reuse is highly simplified by having this defined in just one place
• Adjust to relative changes: You may want data from a time relative to the time of execution, for example, “4 hours ago”.

Defining variables

Variables in CRMint can be defined either globally or per-pipeline. Where a variable is defined with the same name both globally and in a pipeline, the pipeline version will take precedence.

To add varlables to a pipeline:

1. In the pipelines view, click on the pipeline, then click Edit.
2. Click Add variable, then enter the name by which the variable should be referenced, and the value required.

To add a global variable:

1. Click on the Settings button in the top navigation bar
2. Click Add global variable, and add your variable as per a pipeline

Using variables

To use your variable simply enclose the variable name in any parameter in your pipeline with ``

For example, if you have many pipelines, all working with BigQuery, you can set a global variable for the project as follows

Name: PROJECT_ID
Value: my-project-123456

In your BQToMeasurementProtocol worker, you can then set Project ID to:

On execution, the value my-project-123456 from the global variable is substituted into the worker Project ID.

A more complex example might be setting the comment parameter for a Commenter worker:

Finished execution using project 

This would lead to a log message: Finished execution using project my-project-123456

Evaluation

Not only do the `` tags enable variables to be substituted into parameters, as shown above, but they also allow evaluation, for example, setting a parameter Number of Days to:

4

Would use a value of 28.

Would use the value of variable NUM_WEEKS - assuming it has been defined - multiplied by 7.

The full detail of what can be achieved using expressions can be seen in the Jinja2 Expressions syntax guide.

Built-in functions

To make evaluation more useful when working with time-based and analytical data, the following built in functions can be used in expressions:

All examples given at 2018-10-16 12:00:00 UTC