added syspatch exporter

syspatch/syspatch.go

@@ -0,0 +1,72 @@
+// Copyright (C) 2020 Marius Schellenberger
+
+package syspatch
+
+import (
+	"bytes"
+	"github.com/go-kit/kit/log"
+	"github.com/go-kit/kit/log/level"
+	"github.com/prometheus/client_golang/prometheus"
+	"os/exec"
+	"sync"
+	"time"
+)
+
+const (
+	namespace = "syspatch"
+	syspatch  = "/usr/sbin/syspatch"
+
+	errUpdateInterval = time.Second * 30
+	updateInterval    = time.Hour * 2
+)
+
+type Collector struct {
+	sync.RWMutex
+	patches *prometheus.Desc
+	logger  log.Logger
+
+	num float64
+}
+
+// NewCollector returns a new Collector exposing rcctl statistics.
+func NewCollector(logger log.Logger) (*Collector, error) {
+	c := &Collector{
+		patches: prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "", "patches_available"),
+			"Number of syspatch patches available.",
+			nil, nil,
+		),
+		logger: logger,
+	}
+	go c.getPatches()
+	return c, nil
+}
+
+func (c *Collector) getPatches() {
+	for {
+		cmd := exec.Command(syspatch, "-c")
+		out, err := cmd.Output()
+		if err != nil {
+			level.Debug(c.logger).Log("msg", "syspatch list patches", "error", err)
+			time.Sleep(errUpdateInterval)
+			continue
+		}
+		num := float64(bytes.Count(out, []byte("\n")))
+		c.Lock()
+		c.num = num
+		c.Unlock()
+		time.Sleep(updateInterval)
+	}
+}
+
+func (c *Collector) Collect(ch chan<- prometheus.Metric) {
+	c.RLock()
+	num := c.num
+	c.RUnlock()
+	ch <- prometheus.MustNewConstMetric(
+		c.patches, prometheus.GaugeValue, num)
+}
+
+func (c *Collector) Describe(desc chan<- *prometheus.Desc) {
+	desc <- c.patches
+}