Caution
Grafana Alloy is the new name for our distribution of the OTel collector. Grafana Agent has been deprecated and is in Long-Term Support (LTS) through October 31, 2025. Grafana Agent will reach an End-of-Life (EOL) on November 1, 2025. Read more about why we recommend migrating to Grafana Alloy.
Important: This documentation is about an older version. It's relevant only to the release noted, many of the features and functions have been updated or replaced. Please view the current version.
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
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 may contain:
- 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 are not
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:
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
}
}