Custom components

Custom components are a way to create new components from a pipeline of built-in and other custom components.

A custom component includes:

Arguments: Settings that configure the custom component.
Exports: Values the custom component exposes to its consumers.
Components: Built-in and custom components that run as part of the custom component.

Create custom components

Use the declare configuration block to create a new custom component. The block’s label specifies the custom component’s name.

You can use the following configuration blocks inside a declare block:

argument: Define a named argument whose current value you can reference using the expression argument.NAME.value. The user of the custom component determines argument values.
export: Define a named value to expose to custom component users.

Custom components are helpful for reusing a common pipeline multiple times. To learn how to share custom components across files, refer to Modules.

Example

This example creates a custom component called add, which exports the sum of two arguments:

alloy
declare "add" {
    argument "a" { }
    argument "b" { }

    export "sum" {
        value = argument.a.value + argument.b.value
    }
}

add "example" {
    a = 15
    b = 17
}

// add.example.sum == 32