Add Leases collector

collectors/lease_collector.go

@@ -0,0 +1,104 @@
+package collectors
+
+import (
+	"github.com/DRuggeri/dhcpdleasesreader"
+	"github.com/prometheus/client_golang/prometheus"
+	"time"
+)
+
+type leaseCollector struct {
+	activeDesc   *prometheus.Desc
+	info        *dhcpdleasesreader.DhcpdInfo
+
+	scrapesTotalMetric      prometheus.Counter
+	scrapeErrorsTotalMetric prometheus.Counter
+	lastScrapeErrorDesc     *prometheus.Desc
+	lastScrapeTimestampDesc *prometheus.Desc
+	lastScrapeDurationDesc  *prometheus.Desc
+}
+
+func NewLeaseCollector(namespace string, info *dhcpdleasesreader.DhcpdInfo) *leaseCollector {
+	activeDesc := prometheus.NewDesc(prometheus.BuildFQName(namespace, "active", "client"),
+		"The number of leases in dhcpd.leases that have not yet expired",
+		[]string{"hostname", "ip", "mac"}, nil,
+	)
+
+	scrapesTotalMetric := prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: namespace,
+			Subsystem: "active",
+			Name:      "scrapes_total",
+			Help:      "Total number of scrapes",
+		},
+	)
+
+	scrapeErrorsTotalMetric := prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: namespace,
+			Subsystem: "active",
+			Name:      "scrape_errors_total",
+			Help:      "Total number of scrapes errors",
+		},
+	)
+
+	lastScrapeErrorDesc := prometheus.NewDesc(prometheus.BuildFQName(namespace, "active", "last_scrape_error"),
+		"Whether the last scrape resulted in an error (1 for error, 0 for success).",
+		nil, nil,
+	)
+
+	lastScrapeTimestampDesc := prometheus.NewDesc(prometheus.BuildFQName(namespace, "active", "last_scrape_timestamp"),
+		"Number of seconds since 1970 since last scrape.",
+		nil, nil,
+	)
+
+	lastScrapeDurationDesc := prometheus.NewDesc(prometheus.BuildFQName(namespace, "active", "last_scrape_duration_seconds"),
+		"Number of seconds the last scrape took",
+		nil, nil,
+	)
+
+	return &leaseCollector{
+		activeDesc:   activeDesc,
+                info:        info,
+
+		scrapesTotalMetric:      scrapesTotalMetric,
+		scrapeErrorsTotalMetric: scrapeErrorsTotalMetric,
+		lastScrapeErrorDesc:     lastScrapeErrorDesc,
+		lastScrapeTimestampDesc: lastScrapeTimestampDesc,
+		lastScrapeDurationDesc:  lastScrapeDurationDesc,
+	}
+}
+
+func (c *leaseCollector) Collect(ch chan<- prometheus.Metric) {
+	var begun = time.Now()
+	err_num := 0
+
+	/* TODO: Surface read errors through this function */
+	c.info.Read()
+
+	c.scrapesTotalMetric.Inc()
+	if err_num != 0 {
+		c.scrapeErrorsTotalMetric.Inc()
+	}
+
+	for address, lease := range c.info.Leases {
+		if begun.Before(lease.Ends) {
+			ch <- prometheus.MustNewConstMetric(c.activeDesc, prometheus.GaugeValue, float64(1), lease.Hostname, address, lease.Hardware_address)
+		}
+	}
+
+	ch <- c.scrapesTotalMetric
+	ch <- c.scrapeErrorsTotalMetric
+	ch <- prometheus.MustNewConstMetric(c.lastScrapeErrorDesc, prometheus.GaugeValue, float64(err_num))
+	ch <- prometheus.MustNewConstMetric(c.lastScrapeTimestampDesc, prometheus.GaugeValue, float64(time.Now().Unix()))
+	ch <- prometheus.MustNewConstMetric(c.lastScrapeDurationDesc, prometheus.GaugeValue, time.Since(begun).Seconds())
+}
+
+func (c *leaseCollector) Describe(ch chan<- *prometheus.Desc) {
+	ch <- c.activeDesc
+
+	c.scrapesTotalMetric.Describe(ch)
+	c.scrapeErrorsTotalMetric.Describe(ch)
+	ch <- c.lastScrapeErrorDesc
+	ch <- c.lastScrapeTimestampDesc
+	ch <- c.lastScrapeDurationDesc
+}