Function Block Definition

A function block is a versioned, reusable unit of automation logic. Developers write them in Python using the Worker SDK. The workflow engine stores their metadata, validates their schemas, and orchestrates their execution as part of workflows.

Identity

Every function block is identified by three components:

Field	Example	Purpose
package	fb.neops.io	Namespace (reverse domain notation)
name	ping	Operation name
version	1.0.0	Semantic version (major.minor.patch)

Combined into a SemVer identifier: fb.neops.io/ping:1.0.0

Metadata

When a function block is registered, the engine stores:

Property	Type	Description
parameterJsonSchema	JSON Schema	Validates input parameters
resultDataJsonSchema	JSON Schema	Validates output data
runOn	device | group | interface	Entity type this FB operates on
fbType	facts | configure | check | execute | none	Category
isPure	boolean	No side effects (read-only)
isIdempotent	boolean	Safe to re-run with same inputs
description	string	Human-readable description
markdownHelpText	string	Extended documentation (markdown)
deprecated	boolean	Soft-deleted, still available for existing workflows

Usage in Workflows

Workflows reference function blocks in step definitions:

steps:
  - type: functionBlock
    label: ping
    functionBlock: "fb.neops.io/ping:1.0.0"
    runOn: device
    parameters:
      host: "{{ context.device.ip }}"
      timeout: 5

The engine validates that:

• The referenced function block exists and is not deprecated
• The parameters match the function block's parameterJsonSchema
• The runOn value is compatible with the function block's runOn declaration

Types

The fbType categorizes function blocks for organization and filtering:

Type	Description	Typical use
facts	Collect data from devices	show version, interface counters, SNMP
configure	Push configuration to devices	Interface config, ACLs, routing
check	Validate compliance or state	Policy checks, config drift detection
execute	General-purpose operations	Discovery, report generation
none	Utility (no direct device interaction)	Data transformation, aggregation

The type is informational -- it does not affect execution behavior. It is primarily used for UI grouping and search.