confdroid_alloy/templates/config.alloy.erb

<% if @ay_manage_loki == true -%>

// Define file discovery for your logs
local.file_match "system_logs" {
  path_targets = [
<% @log_targets_array.each do |target| -%>
    {__path__ = "<%= target %>"},
<% end -%>
  ]
  sync_period = "5s"
}

// Scrape the logs from the matched files
loki.source.file "system_logs" {
  targets    = local.file_match.system_logs.targets
  forward_to = [loki.relabel.add_labels.receiver]
}

// Parse hostname from log lines (if structured)
loki.process "parse_hostname" {
  forward_to = [loki.relabel.add_labels.receiver]
  stage.match {
    selector = "{filename=~\"/var/log/.*\"}"
    stage.regex {
      expression = "^(?P<timestamp>[^ ]+ [^ ]+) (?P<hostname>[^ ]+) .*"
      source     = "__content__"
    }
    stage.labels {
      values = {
        hostname = "hostname",  // Extracted from log line
      }
    }
  }
  // Fallback: Set hostname explicitly if not parsed
  stage.static_labels {
    values = {
      hostname_fallback = system.hostname,  // e.g., fm002
    }
  }
}

// Refine labels
loki.relabel "add_labels" {
  forward_to = [loki.write.loki.receiver]
  rule {
    action       = "replace"
    target_label = "job"
    replacement  = "syslogs"
  }
  rule {
    source_labels = ["__path__"]
    target_label  = "filename"
  }
  // Prefer parsed hostname, fallback to system.hostname
  rule {
    source_labels = ["hostname"]
    target_label  = "hostname"
  }
  rule {
    source_labels = ["hostname_fallback"]
    target_label  = "hostname"
    action        = "replace"
    replacement   = "${__label:hostname_fallback}"  // Only if hostname is unset
  }
}

loki.write "loki" {
  endpoint {
    url = "<%= @ay_loki_url %>"
    basic_auth {
      username = "<%= @ay_loki_username %>"
      password = "<%= @ay_loki_userpass %>"
    }
  }
}
<% end -%>
<% if @ay_manage_prom == true -%>
// Metrics collection
prometheus.exporter.unix "system_metrics" {
  include_exporter_metrics = true
  disable_collectors       = ["mdadm"]
}

prometheus.scrape "scrape_system" {
  targets    = prometheus.exporter.unix.system_metrics.targets
  forward_to = [prometheus.remote_write.prometheus.receiver]
  scrape_interval = "15s"
}

prometheus.remote_write "prometheus" {
  endpoint {
    url = "<%= @ay_prom_url %>"
    basic_auth {
      username = "<%= @ay_loki_username %>"
      password = "<%= @ay_loki_userpass %>"
    }
  }
}
<% end %>