Global Variables Library

What Are Global Variables​

Global Variables are reusable JavaScript expressions that can be accessed in Functions in any Pipeline. You can access the library from Cribl Stream’s top nav under Processing > Knowledge > Global Variables.

Typical use cases for Global Variables include:

  • Storing a constant that you can reference from any Function in any Pipeline.
  • Storing a relatively long value expression, or one that uses one or more arguments.

Global Variables can be of the following types:

  • Number
  • String
  • Boolean
  • Object
  • Array
  • Expression

Global Variables can be accessed via C.vars. – which can be called anywhere in Cribl Stream that JS expressions are supported. Typeahead is provided. More on Cribl Expressions here.

Examples​

Scenario 1:​

Assign field foo the value in theAnswer Global Variable.

  • Global Variable Name: theAnswer <– ships with Cribl Stream by default.
  • Global Variable Value: 42
  • Sample Eval Function: foo = C.vars.theAnswer

Scenario 2:​

Assign field nowEpoch the current time, in epoch format.

  • Global Variable Name: epoch <– ships with Cribl Stream by default.
  • Global Variable Value: Date.now()/1000
  • Sample Eval Function: nowEpoch = C.vars.epoch()

Scenario 3:​

Create a new field called storage, by converting the value of event field size to human-readable format.

  • Global Variable Name: convertBytes <– ships with Cribl Stream by default

  • Global Variable Value: `${Math.round(bytes / Math.pow(1024, (Math.floor(Math.log(bytes) / Math.log(1024)))), 2)}${['Bytes', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB'][(Math.floor(Math.log(bytes) / Math.log(1024)))]}`
    Note the use of quotes or backticks around values. Use the opposite delimiter for the enclosing expression.

  • Global Variable Argument: bytes

  • Sample Eval Function: storage = C.vars.convertBytes(size)
    Note the use of bytes here as an argument.