Variable insertion

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Variable insertion (also known as interpolation) dynamically modifies string expressions or objects at runtime.

Usage Engine uses curly brackets to indicate variable insertion. It is supported in configuration settings for many functions, including Script, Script aggregator, and various forwarder functions.

Within the curly brackets, you can access variables from different scopes and use them to generate dynamically changed output at runtime. The output type depends on the prefix used:

• $ prefix: Returns a string representation

• @ prefix: Returns the object value directly

Functions supporting variable insertion

Variable insertion is available in configuration settings for many functions. The specific fields that support interpolation are indicated in each function's documentation. Common functions that support variable insertion include:

• ScriptPreview - and Script aggregatorPreview to reference payload, meta, and sharedStore data in JavaScript code by using ${} and @{}.

• DatabasePreview - to insert values from the payload into SQL statements.

• Amazon S3 forwarderPreview - to create dynamic folder paths and filenames.

• HTTP clientPreview - to build target URLs, query parameters, headers, and request bodies.

• Email notificationPreview - to build dynamic values in the From, Recipients, Subject, and Message fields.

Check the individual function documentation to see which configuration fields support variable insertion.

Supported scopes

Usage Engine supports variable insertion using the following scopes:

See ‘Scope details’ below for more information.