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DocumentationGrafana AgentFlow modeReferenceConfiguration blocksdeclare

declare block

declare is an optional configuration block used to define a new [custom component][]. declare blocks must be given a label that determines the name of the custom component.

Example

river Copy

declare "COMPONENT_NAME" {
    COMPONENT_DEFINITION
}

Arguments

The declare block has no predefined schema for its arguments. The body of the declare block is used as the component definition. The body can contain the following:

• argument blocks
• export blocks
• declare blocks
• import blocks
• Component definitions (either built-in or custom components)

The declare block may not contain any configuration blocks that aren’t listed above.

Exported fields

The declare block has no predefined schema for its exports. The fields exported by the declare block are determined by the export blocks found in its definition.

Example

This example creates and uses a custom component that self-collects process metrics and forwards them to an argument specified by the user of the custom component:

river Copy

declare "self_collect" {
  argument "metrics_output" {
    optional = false
    comment  = "Where to send collected metrics."
  }

  prometheus.scrape "selfmonitor" {
    targets = [{
      __address__ = "127.0.0.1:12345",
    }]

    forward_to = [argument.metrics_output.value]
  }
}

self_collect "example" {
  metrics_output = prometheus.remote_write.example.receiver
}

prometheus.remote_write "example" {
  endpoint {
    url = REMOTE_WRITE_URL
  }
}