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.
argument block
argument
is an optional configuration block used to specify parameterized input to a custom component.
argument
blocks must be given a label which determines the name of the argument.
The argument
block may only be specified inside the definition of a declare
block.
Note
In classic modules, theargument
block is valid as a top-level block in a classic module. Classic modules are deprecated and scheduled to be removed in the release after v0.40.
Example
argument "ARGUMENT_NAME" {}
Arguments
Note
For clarity, “argument” in this section refers to arguments which can be given to the argument block. “Module argument” refers to the argument being defined for a module, determined by the label of the argument block.
The following arguments are supported:
Name | Type | Description | Default | Required |
---|---|---|---|---|
comment | string | Description for the argument. | false | no |
default | any | Default value for the argument. | null | no |
optional | bool | Whether the argument may be omitted. | false | no |
By default, all module arguments are required.
The optional
argument can be used to mark the module argument as optional.
When optional
is true
, the initial value for the module argument is specified by default
.
Exported fields
The following fields are exported and can be referenced by other components:
Name | Type | Description |
---|---|---|
value | any | The current value of the argument. |
If you use a custom component, you are responsible for determining the values for arguments.
Other expressions within a custom component may use argument.ARGUMENT_NAME.value
to retrieve the value you provide.
Example
This example creates 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]
}
}