What Are Global Variables

Global Variables are reusable JavaScript expressions that can be accessed in Functions in any Pipeline. You can access the library under 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 LogStream 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 LogStream 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 LogStream 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 LogStream 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.