initial: NAS agent runner setup

_lib.sh

@@ -0,0 +1,36 @@
+#!/usr/bin/env bash
+# _lib.sh — gedeelde helpers; source vanuit andere scripts
+
+: "${AGENT_STATE_DIR:=/var/run/agent}"
+: "${AGENT_LOG_DIR:=/var/log/agent}"
+
+log() {
+    printf '[%s] [%s] %s\n' \
+        "$(date -u +%Y-%m-%dT%H:%M:%SZ)" \
+        "${0##*/}" \
+        "$*" >&2
+}
+
+# Schrijf JSON-state atomisch (write tmp + rename).
+# Argument: JSON-string. Voegt automatisch $.heartbeatAt = now toe.
+write_state() {
+    local payload="$1"
+    local tmp="${AGENT_STATE_DIR}/state.json.tmp.$$"
+    local final="${AGENT_STATE_DIR}/state.json"
+
+    # Merge $payload met heartbeatAt; behoud andere bestaande keys door
+    # de bestaande state in te lezen en payload daarover te leggen.
+    local existing='{}'
+    if [[ -f "$final" ]]; then
+        existing=$(cat "$final" 2>/dev/null || echo '{}')
+    fi
+
+    jq -n \
+        --argjson existing "$existing" \
+        --argjson payload "$payload" \
+        --arg now "$(date -u +%Y-%m-%dT%H:%M:%SZ)" \
+        '$existing + $payload + {heartbeatAt: $now}' \
+        > "$tmp"
+
+    mv "$tmp" "$final"
+}