Added /proc/sys/vm/ collector

Signed-off-by: Ravindra <ravinstra5876@gmail.com>

README.md

@@ -213,6 +213,7 @@ tcpstat | Exposes TCP connection status information from `/proc/net/tcp` and `/p
 wifi | Exposes WiFi device and station statistics. | Linux
 xfrm | Exposes statistics from `/proc/net/xfrm_stat` | Linux
 zoneinfo | Exposes NUMA memory zone metrics. | Linux
+vm_sysctl | Exposes statistics from `/proc/sys/vm` | Linux
 
 ### Deprecated
 

collector/vm_sysctl_linux.go

@@ -0,0 +1,90 @@
+// Copyright 2015 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build linux
+// +build linux
+
+package collector
+
+import (
+	"fmt"
+	"github.com/prometheus/client_golang/prometheus"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+const vmSysctlPath = "/proc/sys/vm"
+
+type vmCollector struct {
+	logger *slog.Logger
+	desc   *prometheus.Desc
+}
+
+func init() {
+	registerCollector("vm_sysctl", defaultDisabled, VMSysctlCollector)
+}
+
+func VMSysctlCollector(logger *slog.Logger) (Collector, error) {
+	return &vmCollector{
+		logger: logger,
+	}, nil
+}
+
+func (c *vmCollector) Update(ch chan<- prometheus.Metric) error {
+	entries, err := os.ReadDir(vmSysctlPath)
+	if err != nil {
+		return fmt.Errorf("error reading %s: %w", vmSysctlPath, err)
+	}
+
+	for _, entry := range entries {
+		if entry.IsDir() {
+			continue // skip subdirectories
+		}
+
+		name := entry.Name()
+		fullPath := filepath.Join(vmSysctlPath, name)
+
+		data, err := os.ReadFile(fullPath)
+		if err != nil {
+			c.logger.Warn("failed to read vm sysctl file", "file", fullPath, "err", err)
+			continue
+		}
+
+		valStr := strings.TrimSpace(string(data))
+		val, err := strconv.ParseFloat(valStr, 64)
+		if err != nil {
+			// If file is not numeric, skip it silently
+			continue
+		}
+
+		metricName := prometheus.BuildFQName("node", "vm_sysctl", sanitizeMetricName(name))
+		desc := prometheus.NewDesc(metricName, fmt.Sprintf("Value of /proc/sys/vm/%s", name), nil, nil)
+
+		ch <- prometheus.MustNewConstMetric(desc, prometheus.GaugeValue, val)
+	}
+
+	return nil
+}
+
+// sanitizeMetricName replaces invalid chars with underscores (only allow a-z, 0-9, and _)
+func sanitizeMetricName(name string) string {
+	name = strings.ReplaceAll(name, "-", "_")
+	name = strings.ReplaceAll(name, ".", "_")
+
+	// If needed, add more replacements here
+
+	return name
+}