grafana: re-organize

services/grafana/disk-usage-collector.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+# Collects ZFS pool utilization and boot partition usage for Prometheus textfile collector
+set -euo pipefail
+
+TEXTFILE="${TEXTFILE:?TEXTFILE env required}"
+TMP="${TEXTFILE}.$$"
+
+{
+  echo '# HELP zpool_size_bytes Total size of ZFS pool in bytes'
+  echo '# TYPE zpool_size_bytes gauge'
+  echo '# HELP zpool_used_bytes Used space in ZFS pool in bytes'
+  echo '# TYPE zpool_used_bytes gauge'
+  echo '# HELP zpool_free_bytes Free space in ZFS pool in bytes'
+  echo '# TYPE zpool_free_bytes gauge'
+
+  # -Hp: scripting mode, parseable, bytes
+  zpool list -Hp -o name,size,alloc,free | while IFS=$'\t' read -r name size alloc free; do
+    echo "zpool_size_bytes{pool=\"${name}\"} ${size}"
+    echo "zpool_used_bytes{pool=\"${name}\"} ${alloc}"
+    echo "zpool_free_bytes{pool=\"${name}\"} ${free}"
+  done
+
+  echo '# HELP partition_size_bytes Total size of partition in bytes'
+  echo '# TYPE partition_size_bytes gauge'
+  echo '# HELP partition_used_bytes Used space on partition in bytes'
+  echo '# TYPE partition_used_bytes gauge'
+  echo '# HELP partition_free_bytes Free space on partition in bytes'
+  echo '# TYPE partition_free_bytes gauge'
+
+  # Boot drive partitions: /boot (ESP), /persistent, /nix
+  # Use df with 1K blocks and convert to bytes
+  for mount in /boot /persistent /nix; do
+    if mountpoint -q "$mount" 2>/dev/null; then
+      read -r size used avail _ <<< "$(df -k --output=size,used,avail "$mount" | tail -1)"
+      size_b=$((size * 1024))
+      used_b=$((used * 1024))
+      avail_b=$((avail * 1024))
+      echo "partition_size_bytes{mount=\"${mount}\"} ${size_b}"
+      echo "partition_used_bytes{mount=\"${mount}\"} ${used_b}"
+      echo "partition_free_bytes{mount=\"${mount}\"} ${avail_b}"
+    fi
+  done
+} > "$TMP"
+mv "$TMP" "$TEXTFILE"