Templating

Templates are a way to define new Wombat components (similar to plugins) that are implemented by generating a Wombat config snippet from pre-defined parameter fields. This is useful when a common pattern of Wombat configuration is used but with varying parameters each time.

How to define and use templates?

A template is defined in a YAML file that can be imported when Wombat runs using the flag -t:

wombat -t "./templates/*.yaml" -c ./config.yaml

The template describes the type of the component and configuration fields that can be used to customize it, followed by a Bloblang mapping that translates an object containing those fields into a wombat config structure. This allows you to use logic to generate more complex configurations:

name: aws_sqs_list
type: input
fields:
  - name: urls
    type: string
    kind: list
  - name: region
    type: string
    default: us-east-1
mapping: |
  root.broker.inputs = this.urls.map_each(url -> {
    "aws_sqs": {
      "url": url,
      "region": this.region,
    }
  })

input:
  aws_sqs_list:
    urls:
      - https://sqs.us-east-2.amazonaws.com/123456789012/MyQueue1
      - https://sqs.us-east-2.amazonaws.com/123456789012/MyQueue2

pipeline:
  processors:
    - mapping: |
        root.id = uuid_v4()
        root.foo = this.inner.foo
        root.body = this.outer

input:
  broker:
    inputs:
      - aws_sqs:
          url: https://sqs.us-east-2.amazonaws.com/123456789012/MyQueue1
          region: us-east-1
      - aws_sqs:
          url: https://sqs.us-east-2.amazonaws.com/123456789012/MyQueue2
          region: us-east-1

pipeline:
  processors:
    - mapping: |
        root.id = uuid_v4()
        root.foo = this.inner.foo
        root.body = this.outer