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Documentation Grafana Agent Grafana Agent Flow Reference Components discovery.file

discovery.file

discovery.file discovers files on the local filesystem using glob patterns and the doublestar library.

Usage

Alloy Copy

discovery.file "LABEL" {
  path_targets = [{"__path__" = "DOUBLESTAR_PATH"}]
}

Arguments

The following arguments are supported:

path_targets uses doublestar style paths.

• /tmp/**/*.log will match all subfolders of tmp and include any files that end in *.log.
• /tmp/apache/*.log will match only files in /tmp/apache/ that end in *.log.
• /tmp/** will match all subfolders of tmp, tmp itself, and all files.

Exported fields

The following fields are exported and can be referenced by other components:

Each target includes the following labels:

• __path__: Absolute path to the file.

Component health

discovery.file is only reported as unhealthy when given an invalid configuration. In those cases, exported fields retain their last healthy values.

Debug information

discovery.file does not expose any component-specific debug information.

Debug metrics

discovery.file does not expose any component-specific debug metrics.

Examples

This example discovers all files and folders under /tmp/logs. The absolute paths are used by loki.source.file.files targets.

Alloy Copy

discovery.file "tmp" {
    path_targets = [{"__path__" = "/tmp/logs/**/*.log"}]
}

loki.source.file "files" {
    targets    = discovery.file.tmp.targets
    forward_to = [ /* ... */ ]
}

Kubernetes

This example finds all the logs on pods and monitors them.

Alloy Copy

discovery.kubernetes "k8s" {
  role = "pod"
}

discovery.relabel "k8s" {
  targets = discovery.kubernetes.k8s.targets
 
  rule {
    source_labels = ["__meta_kubernetes_namespace", "__meta_kubernetes_pod_label_name"]
    target_label  = "job"
    separator     = "/"
  }

  rule {
    source_labels = ["__meta_kubernetes_pod_uid", "__meta_kubernetes_pod_container_name"]
    target_label  = "__path__"
    separator     = "/" 
    replacement   = "/var/log/pods/*$1/*.log"
  } 
}

discovery.file "pods" {
    path_targets = discovery.relabel.k8s.output
}

loki.source.file "pods" {
    targets = discovery.file.pods.targets
    forward_to = [loki.write.endpoint.receiver]
}

loki.write "endpoint" {
    endpoint {
        url = "LOKI_PATH"
        http_client_config {
            basic_auth {
                username = USERNAME
                password = "PASSWORD"
            }
        }
    }
}