logging {
  level = "warn"
}

// ============================================
// LOKI WRITE TARGET
// ============================================
loki.write "loki_srv" {
  endpoint {
    url = sys.env("LOKI_URL")
  }
}

// ============================================
// HOST JOURNALD SOURCE
// ============================================

// Read journald logs from the host
loki.source.journal "journal" {
  max_age   = "24h"
  relabel_rules = discovery.relabel.host_journal.rules
  forward_to    = [loki.process.host_journal.receiver]
}

// ============================================
// HOST JOURNALD RELABELING
// ============================================

// Convert journald metadata into Loki labels
discovery.relabel "host_journal" {
  targets = []

  // Systemd unit name
  rule {
    source_labels = ["__journal__systemd_unit"]
    target_label  = "systemd_unit"
  }

  // Transport type (stdout, syslog, kernel, audit, etc.)
  rule {
    source_labels = ["__journal__transport"]
    target_label  = "journal_transport"
  }

  // Priority (info, warning, error)
  rule {
    source_labels = ["__journal_priority_keyword"]
    target_label  = "level"
  }
}

// ============================================
// HOST JOURNALD PROCESSING
// ============================================

// Add static labels and forward journald logs to Loki
loki.process "host_journal" {
  stage.static_labels {
    values = {
      cluster = sys.env("CLUSTER_NAME"),
      host    = sys.env("HOSTNAME"),
      zone    = sys.env("ZONE"),
      job     = "integrations/journald",
    }
  }

  forward_to = [loki.write.loki_srv.receiver]
}


// ============================================
// Discovery: Kubernetes - pods 
// ============================================
discovery.kubernetes "kube_pods" {
  role = "pod"

	selectors {
		role  = "pod"
		field = "spec.nodeName=" + coalesce(env("HOSTNAME"), constants.hostname)
	}
}


loki.process "kube_pod_logs" {
  stage.static_labels {
    values = {
      cluster   = sys.env("CLUSTER_NAME"),
      zone      = sys.env("ZONE"),
      host      = sys.env("HOSTNAME"),
      node_name = sys.env("HOSTNAME"),
      job       = "integrations/kubernetes/pod-logs",
    }
  }
  forward_to = [loki.write.loki_srv.receiver]
}


// ============================================
// Loki.source  kube_pod_logs
// ============================================

loki.source.kubernetes "kube_pod_logs" {
  targets    = discovery.relabel.kube_pod_logs.output
  forward_to = [loki.process.kube_pod_logs.receiver]
}

discovery.relabel "kube_pod_logs" {
  targets = discovery.kubernetes.kube_pods.targets
  rule {
    source_labels = ["__meta_kubernetes_namespace"]
    target_label  = "namespace"
  }

  rule {
    source_labels = ["__meta_kubernetes_pod_name"]
    regex        = "^(.+?)-[0-9a-zA-Z]{4,16}(?:-[0-9a-zA-Z]{4,16})?$"
    replacement  = "$1"
    target_label = "pod"
  }

  rule {
    source_labels = ["__meta_kubernetes_pod_container_name"]
    target_label = "container"
  }

  rule {
    source_labels = [
      "__meta_kubernetes_pod_controller_name",
    ]
    regex        = "([0-9a-z-.]+?)(-[0-9a-f]{8,10})?"
    target_label = "controller"
  }

  rule {
    source_labels = [
      "__meta_kubernetes_pod_label_app_kubernetes_io_name",
      "__meta_kubernetes_pod_label_app",
      "controller_name",
      "__meta_kubernetes_pod_name",
    ]
    regex        = "^;*([^;]+)(;.*)?$"
    target_label = "app"
  }

}



// ============================================
// Metrics: Prometheus connection config
// ============================================

prometheus.remote_write "prometheus_srv" {
  endpoint {
    url = sys.env("PROMETHEUS_URL")
  }
  
  // global labels
  external_labels = {
    cluster     = sys.env("CLUSTER_NAME"),
    zone        = sys.env("ZONE"),
  }
}


// ============================================
// Metrics: Prometheus Unix Exporter
// ============================================

prometheus.exporter.unix "node_exporter" {
  rootfs_path = "/host"
  disable_collectors = ["ipvs", "btrfs", "infiniband", "xfs", "zfs"]
  enable_collectors = [
    "cpu",
    "meminfo",
    "vmstat",
    "loadavg",
    "filesystem",
    "netdev",
    "uname",
  ]

  filesystem {
    mount_points_exclude = "(^/etc|^/dev|^/proc|^/sys|^/run|/kubelet/.+)($|/)"
    fs_types_exclude     = "^(tmpfs|shm|autofs|binfmt_misc|bpf|cgroup2?|configfs|debugfs|devpts|devtmpfs|fusectl|hugetlbfs|iso9660|mqueue|nsfs|overlay|proc|procfs|pstore|rpc_pipefs|securityfs|selinuxfs|squashfs|sysfs|tracefs|erofs)$"
    mount_timeout        = "5s"
  }

  netclass {
    ignored_devices = "^(veth.*|cali.*|[a-f0-9]{15})$"
  }

  netdev {
    device_exclude = "^(veth.*|cali.*|[a-f0-9]{15})$"
  }
}

prometheus.scrape "node_exporter" {
  targets         = prometheus.exporter.unix.node_exporter.targets
  scrape_interval = "30s"

  forward_to = [prometheus.relabel.node_exporter.receiver]
}

prometheus.relabel "node_exporter" {
  forward_to = [prometheus.remote_write.prometheus_srv.receiver]

  rule {
    action       = "replace"
    replacement  = sys.env("HOSTNAME")
    target_label = "nodename"
  }

  rule {
    action       = "replace"
    replacement  = sys.env("HOSTNAME")
    target_label = "node"
  }
}

// ============================================
// Discovery: Kubernetes - Nodes
// ============================================

discovery.kubernetes "kube_nodes" {
  role = "node"
	selectors {
		role  = "node"
		field = "spec.nodeName=" + coalesce(env("HOSTNAME"), constants.hostname)
	}
}

discovery.relabel "kubelet" {
  targets = discovery.kubernetes.kube_nodes.targets

  rule {
    regex  = ".*_uid$|.*_id$|^annotation_.*|^label_.*|^endpoint_.*|^pod_ip$"
    action = "drop"
  }

  rule {
    regex  = "container_fs_.*|container_network_.*|container_hugetlb_.*|container_blkio_.*|container_tasks_state_.*"
    action = "drop"
  }


  // duplicate metrics from cAdviser
  rule {
    regex  = "container_cpu_usage_seconds_total|container_memory_working_set_bytes|container_memory_rss|container_memory_cache"
    action = "drop"
  }

  rule {
    source_labels = ["__meta_kubernetes_node_address_InternalIP"]
    target_label  = "__address__"
    replacement   = "$1:10250"
  }
  
  rule {
    action        = "replace"
    source_labels = ["__meta_kubernetes_node_name"]
    regex         = "(.+)"
    target_label  = "node"
  }

  rule {
    source_labels = ["node"]
    target_label = "host"
  }


  rule {
    target_label = "__metrics_path__"
    replacement  = "/metrics"
  }

  rule {
    target_label = "cluster"
    replacement  = sys.env("CLUSTER_NAME")
  }

  rule {
    target_label = "zone"
    replacement  = sys.env("ZONE")
  }
}

prometheus.scrape "kubelet" {
  job_name = "integrations/kubernetes/kubelet"
  targets  = discovery.relabel.kubelet.output

  scheme = "https"
  metrics_path = "/metrics"

  tls_config {
    server_name          = "kubernetes"
    ca_file              = "/var/run/secrets/kubernetes.io/serviceaccount/ca.crt"
    insecure_skip_verify = true
  }

  bearer_token_file = "/var/run/secrets/kubernetes.io/serviceaccount/token"

  forward_to = [prometheus.remote_write.prometheus_srv.receiver]
}


// ===========================================================
// Discovery:relabel: kube_node_metrics (cAdviser)
// Requirements: 
//  - discovery.kubernetes.role.node: kube_nodes
// ===========================================================

  discovery.relabel "kube_node_metrics" {
  targets = discovery.kubernetes.kube_nodes.targets

  rule {
    regex  = ".*_uid$|.*_id$|^annotation_.*|^label_.*|^endpoint_.*|^pod_ip$"
    action = "drop"
  }

  rule {
    action        = "replace"
    source_labels = ["__meta_kubernetes_node_name"]
    regex         = "(.+)"
    target_label  = "node"
  }

  rule {
    source_labels = ["node"]
    target_label = "host"
  }

  rule {
    replacement  = "/metrics/cadvisor"
    target_label = "__metrics_path__"
  }

  rule {
    target_label = "cluster"
    replacement  = sys.env("CLUSTER_NAME")
  }

  rule {
    target_label = "zone"
    replacement  = sys.env("ZONE")
  }
}


// ===============================================================================
// Scrape Kubernetes pods containers metrics / cAdvisor
// Requirements: 
//  - discovery.relabel - kube_node_metrics
// ===============================================================================

prometheus.scrape "cadvisor" {
  job_name = "integrations/kubernetes/cadvisor"
  targets  = discovery.relabel.kube_node_metrics.output
  scheme   = "https"

  tls_config {
    server_name          = "kubernetes"
    ca_file              = "/var/run/secrets/kubernetes.io/serviceaccount/ca.crt"
    insecure_skip_verify = true
  }

  bearer_token_file = "/var/run/secrets/kubernetes.io/serviceaccount/token"
  forward_to        = [prometheus.remote_write.prometheus_srv.receiver]
}

// ============================================
// Discovery: Kubernetes - endpoints
// used by:
// - loki kubernetes kube state metrics
// ============================================
discovery.kubernetes "kube_endpoints" {
  role = "endpoints"
}



// ===============================================================================
// prometheus / Metrics - Scrape kube_state_metrics
// Requirements: 
//  - discovery.relabel - kube_state_metrics
// ===============================================================================
prometheus.scrape "kube_state_metrics" {
  job_name = "integrations/kubernetes/kube-state-metrics"
  targets  = discovery.relabel.kube_state_metrics.output

  scheme = "http"

  forward_to = [prometheus.remote_write.prometheus_srv.receiver]
}

discovery.relabel "kube_state_metrics" {
  targets = discovery.kubernetes.kube_endpoints.targets

 rule {
    source_labels = ["__meta_kubernetes_endpoint_node_name"]
    regex         = coalesce(env("HOSTNAME"), constants.hostname)
    action        = "keep"
  }
  
  rule {
    source_labels = ["__meta_kubernetes_service_name"]
    regex         = "kube-state-metrics"
    action        = "keep"
  }

  rule {
    regex  = ".*_uid$|.*_id$|^annotation_.*|^label_.*|^endpoint_.*|^pod_ip$"
    action = "drop"
  }

  rule {
    target_label = "cluster"
    replacement  = sys.env("CLUSTER_NAME")
  }

  rule {
    target_label = "zone"
    replacement  = sys.env("ZONE")
  }
}