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User-defined Functions are named, reusable expressions in Sift, written using the Common Expression Language (CEL). They can be referenced across multiple Rules and Calculated Channels to centralize logic and reduce duplication. Each User-defined Function includes a CEL expression and optional parameters. Functions are version-controlled, allowing teams to update logic safely over time while preserving existing behavior. A User-defined Function can be previewed, edited, archived, and unarchived. User-defined Functions are designed for consistency and maintainability, supporting common use cases such as thresholding, comparison logic, and shared computation patterns across telemetry analysis workflows.

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Lifecycle actions

Each User-defined Function in Sift supports the following lifecycle actions:
ActionDescription
PreviewEvaluate the User-defined Function using a selected Run and mapped Channels to observe its behavior with real data before using it in expressions.
EditUpdate the User-defined Function’s expression, input Channels, or description.
ArchiveRemove the User-defined Function from use in new Rules or Calculated Channels.
UnarchiveRestore a previously archived User-defined Function, making it available again for use in new expressions. Anyone in the organization can perform this action.