data "docker_registry_image" "node_exporter" {
  name = "prom/node-exporter"
}

locals {
  labels_node_exporter = {
    "shepherd.auto-update" = "true",
    "prometheus.job"       = "node",
    "prometheus.port"      = "9100",
  }
}

resource "docker_service" "node_exporter" {
  name = "prometheus_node_exporter"

  mode {
    global = true
  }

  dynamic "labels" {
    for_each = local.labels_node_exporter
    content {
      label = labels.key
      value = labels.value
    }
  }

  task_spec {
    networks_advanced {
      name = docker_network.metrics.id
    }

    container_spec {
      image = "${data.docker_registry_image.node_exporter.name}@${data.docker_registry_image.node_exporter.sha256_digest}"

      args = [
        "--path.rootfs=/host/root",
        "--path.procfs=/host/proc",
        "--path.sysfs=/host/sys",
        "--collector.filesystem.ignored-mount-points=^/(sys|proc|dev|host|etc)($|/)"
      ]
      mounts {
        target    = "/host/root"
        source    = "/"
        type      = "bind"
        read_only = true
      }

      mounts {
        target    = "/host/proc"
        source    = "/proc"
        type      = "bind"
        read_only = true
      }

      mounts {
        target    = "/host/sys"
        source    = "/sys"
        type      = "bind"
        read_only = true
      }
    }
  }
}