Variable insertion

Variable insertion

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

UsageCloud 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 described in each function's documentation. Common functions that support variable insertion include:

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

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

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

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

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

See the documentation for each function to see which configuration fields support variable insertion.

Supported scopes

UsageCloud supports variable insertion using the following scopes:

Scope

Description

Availability

Scope

Description

Availability

payload

Data from the current record flowing through the stream

Processor and forwarder functions only

meta

Metadata providing additional context about the data

Processor and forwarder functions only

sharedStore

Data stored in the shared store, loaded at stream start

All functions

See Variable insertion scope details for more information.