Documentation Grafana Alloy Get started Configuration syntax Expressions Referencing component exports

Reference component exports

Referencing exports allows Alloy to configure and connect components dynamically using expressions. While components can work independently, they’re more effective when one component’s behavior and data flow depend on another component’s exports, creating a dependency relationship.

Such references can only appear in another component’s arguments or a configuration block’s fields. Components can’t reference themselves.

Use references

You create references by combining the component’s name, label, and named export with dots.

For example, you can refer to the contents of a file exported by the local.file component labeled target as local.file.target.content. Similarly, a prometheus.remote_write component instance labeled onprem exposes its receiver for metrics as prometheus.remote_write.onprem.receiver.

The following example demonstrates some references.

alloy Copy

local.file "target" {
  filename = "/etc/alloy/target"
}

prometheus.scrape "default" {
  targets    = [{ "__address__" = local.file.target.content }]
  forward_to = [prometheus.remote_write.onprem.receiver]
}

prometheus.remote_write "onprem" {
  endpoint {
    url = "http://prometheus:9009/api/prom/push"
  }
}

In the preceding example, you created a simple pipeline by writing a few Alloy expressions.

After the value resolves, it must match the type of the attribute it’s assigned to. While you can only configure attributes using the basic Alloy types, the exports of components can use special internal Alloy types, such as Secrets or Capsules, which provide additional functionality.