server-infra/roles/alloy/templates/config.alloy.j2

// Managed by Ansible (roles/alloy). Do not edit by hand.
// host label = inventory hostname: {{ inventory_hostname }}

// =====================================================================
// LOGS
// =====================================================================

loki.source.journal "system" {
  forward_to    = [loki.process.journal_labels.receiver]
  relabel_rules = discovery.relabel.journal.rules
  labels        = {
    job  = "systemd",
    host = "{{ inventory_hostname }}",
  }
}

discovery.relabel "journal" {
  targets = []

  rule {
    source_labels = ["__journal__systemd_unit"]
    target_label  = "unit"
  }
}

loki.process "journal_labels" {
  forward_to = [loki.write.default.receiver]

  stage.static_labels {
    values = {
      env = "host",
      app = "system",
    }
  }
}

discovery.docker "containers" {
  host = "unix:///var/run/docker.sock"
}

discovery.relabel "docker" {
  targets = discovery.docker.containers.targets

  rule {
    source_labels = ["__meta_docker_container_name"]
    regex         = "/(.*)"
    target_label  = "container"
  }

  rule {
    source_labels = ["__meta_docker_container_label_com_docker_compose_project"]
    target_label  = "compose_project"
  }

  rule {
    source_labels = ["__meta_docker_container_label_com_docker_compose_service"]
    target_label  = "compose_service"
  }
}

loki.source.docker "containers" {
  host       = "unix:///var/run/docker.sock"
  targets    = discovery.relabel.docker.output
  forward_to = [loki.process.docker_labels.receiver]
  labels     = {
    job  = "docker",
    host = "{{ inventory_hostname }}",
  }
}

loki.process "docker_labels" {
  forward_to = [loki.write.default.receiver]

  stage.regex {
    source     = "compose_project"
    expression = "^(?P<app>[a-z0-9_]+)_(?P<env>beta|prod)$"
  }

  stage.labels {
    values = {
      app = "",
      env = "",
    }
  }

{% raw %}
  stage.template {
    source   = "env"
    template = `{{ if .env }}{{ .env }}{{ else }}infra{{ end }}`
  }

  stage.template {
    source   = "app"
    template = `{{ if .app }}{{ .app }}{{ else }}{{ .compose_project }}{{ end }}`
  }
{% endraw %}

  stage.labels {
    values = {
      app = "",
      env = "",
    }
  }
}

loki.write "default" {
  endpoint {
    url = "{{ alloy_loki_push_url }}"
  }
}

// =====================================================================
// METRICS — host (CPU / RAM / disk / load / network)
// =====================================================================

prometheus.exporter.unix "node" {
  procfs_path = "/host/proc"
  sysfs_path  = "/host/sys"
  rootfs_path = "/host/root"
}

prometheus.scrape "node" {
  targets         = prometheus.exporter.unix.node.targets
  forward_to      = [prometheus.relabel.add_host.receiver]
  scrape_interval = "15s"
  job_name        = "node"
}

// =====================================================================
// METRICS — Docker containers (cAdvisor)
// =====================================================================

prometheus.exporter.cadvisor "docker" {
  docker_host      = "unix:///var/run/docker.sock"
  docker_only      = true
  storage_duration = "5m"
  store_container_labels = false
  allowlisted_container_labels = [
    "com.docker.compose.project",
    "com.docker.compose.service",
  ]
}

prometheus.scrape "cadvisor" {
  targets         = prometheus.exporter.cadvisor.docker.targets
  forward_to      = [prometheus.relabel.cadvisor_labels.receiver]
  scrape_interval = "15s"
  job_name        = "cadvisor"
}

prometheus.relabel "cadvisor_labels" {
  forward_to = [prometheus.remote_write.default.receiver]

  rule {
    target_label = "host"
    replacement  = "{{ inventory_hostname }}"
  }

  rule {
    source_labels = ["container_label_com_docker_compose_project"]
    target_label  = "compose_project"
  }

  rule {
    source_labels = ["compose_project"]
    regex         = "^([a-z0-9_]+)_(beta|prod)$"
    target_label  = "app"
    replacement   = "${1}"
  }

  rule {
    source_labels = ["compose_project"]
    regex         = "^([a-z0-9_]+)_(beta|prod)$"
    target_label  = "env"
    replacement   = "${2}"
  }

  rule {
    source_labels = ["env"]
    regex         = "^$"
    target_label  = "env"
    replacement   = "infra"
  }

  rule {
    source_labels = ["app"]
    regex         = "^$"
    target_label  = "app"
    replacement   = "infra"
  }
}

prometheus.relabel "add_host" {
  forward_to = [prometheus.remote_write.default.receiver]

  rule {
    target_label = "host"
    replacement  = "{{ inventory_hostname }}"
  }
}

prometheus.remote_write "default" {
  endpoint {
    url = "{{ alloy_prometheus_remote_write_url }}"
  }
}