Create Dynamic Variable Names

A variable can reference the value of another existing variable. In an expression, this requires square brackets:

${scope[variable]}

This is a dynamic variable. When MEP encounters an expression like this it resolves the value of the variable in square brackets before processing the expression.

For example, to create a service variable that updates to a new name every day, you could use the Variables > Set handler to create a variable with:

  • service as the scope
  • ${system.date} as the key
  • 1 as the default (or initial) value
  • ${service[system.date] + 1} as the value

The value ${service[system.date]} counts the number of times the handler was triggered. Each day, a new variable would be generated, and you would then see each day’s variable with its own value; for example:

Variable

Description

service.2010-10-21

1478

service.2010-10-20

2231

service.2010-10-19

796

If you wanted to reference this variable in a handler, you would use the format:

${service[system.date]}