Initial commit

Author: DRuggeri

.gitignore

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+*_exporter
+scripts/github_api_token
+tmp/

CONTRIBUTING.md

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+Hello there - glad to see you're interested in contributing!
+
+This is a personal project and I bet that it'll be used by other hobbyists, so I am more than happy to support adding your pull request that...
+ - Explains what you're adding/removing/changing
+ - Passes test cases
+ - Doesn't expand the project beyond its intended scope

LICENSE

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+Copyright 2020 Daniel Ruggeri
+
+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.

README.md

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+# ISC dhcpd Leases Prometheus Exporter
+
+A [Prometheus](https://prometheus.io) exporter for the ISC dhcpd server. This exporter consumes the `dhcpd.leases` file which is periodically written by the dameon. It is based on the [node_exporter](https://github.com/prometheus/node_exporter) and [cf_exporter](https://github.com/bosh-prometheus/cf_exporter) projects.
+
+## Installation
+
+### Binaries
+
+Download the already existing [binaries](https://github.com/DRuggeri/dhcpd_leases_exporter/releases) for your platform:
+
+```bash
+$ ./dhcpd_leases_exporter <flags>
+```
+
+### From source
+
+Using the standard `go install` (you must have [Go](https://golang.org/) already installed in your local machine):
+
+```bash
+$ go install github.com/DRuggeri/dhcpd_leases_exporter
+$ dhcpd_leases_exporter <flags>
+```
+
+## Usage
+
+### Flags
+
+```
+usage: dhcpd_leases_exporter [<flags>]
+
+Flags:
+  -h, --help              Show context-sensitive help (also try --help-long and --help-man).
+      --dhcpd.leases="/var/lib/dhcp/dhcpd.leases"
+                          Path of the dhcpd.leases file. Defaults to '/var/lib/dhcp/dhcpd.leases' ($DHCPD_LEASES_EXPORTER_LEASES_FILE)
+      --filter.collectors="Stats"
+                          Comma separated collectors to enable (Stats) ($DHCPD_LEASES_EXPORTER_FILTER_COLLECTORS)
+      --metrics.namespace="dhcpd_leases"
+                          Metrics Namespace ($DHCPD_LEASES_EXPORTER_METRICS_NAMESPACE)
+      --web.listen-address=":9198"
+                          Address to listen on for web interface and telemetry ($DHCPD_LEASES_EXPORTER_WEB_LISTEN_ADDRESS)
+      --web.telemetry-path="/metrics"
+                          Path under which to expose Prometheus metrics ($DHCPD_LEASES_EXPORTER_WEB_TELEMETRY_PATH)
+      --web.auth.username=WEB.AUTH.USERNAME
+                          Username for web interface basic auth ($DHCPD_LEASES_EXPORTER_WEB_AUTH_USERNAME)
+      --web.auth.password=WEB.AUTH.PASSWORD
+                          Password for web interface basic auth ($DHCPD_LEASES_EXPORTER_WEB_AUTH_PASSWORD)
+      --web.tls.cert_file=WEB.TLS.CERT_FILE
+                          Path to a file that contains the TLS certificate (PEM format). If the certificate is signed by a certificate authority, the file should be the concatenation of the server's certificate, any intermediates, and the CA's certificate
+                          ($DHCPD_LEASES_EXPORTER_WEB_TLS_CERTFILE)
+      --web.tls.key_file=WEB.TLS.KEY_FILE
+                          Path to a file that contains the TLS private key (PEM format) ($DHCPD_LEASES_EXPORTER_WEB_TLS_KEYFILE)
+      --printMetrics      Print the metrics this exporter exposes and exits. Default: false ($DHCPD_LEASES_EXPORTER_PRINT_METRICS)
+      --log.level="info"  Only log messages with the given severity or above. Valid levels: [debug, info, warn, error, fatal]
+      --log.format="logger:stderr"
+                          Set the log target and format. Example: "logger:syslog?appname=bob&local=7" or "logger:stdout?json=true"
+      --version           Show application version.
+```
+
+## Metrics
+
+### Stats
+This collector counts the number of leases PER UNIQUE IP found in dhcpd.leases. This means that if an IP was leased to `client X`, but is now leased to `client Y`, there will be only one entry counted (the most recent one). This is in line with how dhcpd reads the file.
+
+```
+  dhcpd_leases_stats_valid_leases - The number of leases in dhcpd.leases that have not yet expired.
+  dhcpd_leases_stats_expired_leases - The number of leases in dhcpd.leases that have expired.
+  dhcpd_leases_stats_count - The number of leases in dhcpd.leases
+  dhcpd_leases_stats_scrapes_total - Total number of scrapes for stats.
+  dhcpd_leases_stats_scrape_errors_total - Total number of scrapes errors for stats.
+  dhcpd_leases_stats_last_scrape_error - Whether the last scrape of stats resulted in an error (1 for error, 0 for success).
+  dhcpd_leases_stats_last_scrape_timestamp - Number of seconds since 1970 since last scrape of stat metrics.
+```
+
+## Contributing
+
+Refer to the [contributing guidelines](https://github.com/DRuggeri/dhcpd_leases_exporter/blob/master/CONTRIBUTING.md).
+
+## License
+
+Apache License 2.0, see [LICENSE](https://github.com/DRuggeri/dhcpd_leases_exporter/blob/master/LICENSE).

collectors/stats_collector.go

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+package collectors
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"time"
+	"github.com/DRuggeri/dhcpdleasesreader"
+)
+
+type StatCollector struct {
+	namespace   string
+	validMetric prometheus.Gauge
+	expiredMetric prometheus.Gauge
+	countMetric prometheus.Gauge
+	modTimeMetric prometheus.Gauge
+	info       *dhcpdleasesreader.DhcpdInfo
+
+	scrapesTotalMetric              prometheus.Counter
+	scrapeErrorsTotalMetric         prometheus.Counter
+	lastScrapeErrorMetric           prometheus.Gauge
+	lastScrapeTimestampMetric       prometheus.Gauge
+	lastScrapeDurationSecondsMetric prometheus.Gauge
+}
+
+func NewStatsCollector(namespace string, info *dhcpdleasesreader.DhcpdInfo) *StatCollector {
+	validMetric := prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: "stats",
+			Name:      "valid_leases",
+			Help:      "The number of leases in dhcpd.leases that have not yet expired.",
+		},
+	)
+
+	expiredMetric := prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: "stats",
+			Name:      "expired_leases",
+			Help:      "The number of leases in dhcpd.leases that have expired.",
+		},
+	)
+
+	countMetric := prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: "stats",
+			Name:      "count",
+			Help:      "The number of leases in dhcpd.leases",
+		},
+	)
+
+	modTimeMetric := prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: "stats",
+			Name:      "filetime",
+			Help:      "The file timestamp in seconds since epoch of the dhcpd.leases file",
+		},
+	)
+
+
+	scrapesTotalMetric := prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: namespace,
+			Subsystem: "stats",
+			Name:      "scrapes_total",
+			Help:      "Total number of scrapes for stats.",
+		},
+	)
+
+	scrapeErrorsTotalMetric := prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: namespace,
+			Subsystem: "stats",
+			Name:      "scrape_errors_total",
+			Help:      "Total number of scrapes errors for stats.",
+		},
+	)
+
+	lastScrapeErrorMetric := prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: "stats",
+			Name:      "last_scrape_error",
+			Help:      "Whether the last scrape of stats resulted in an error (1 for error, 0 for success).",
+		},
+	)
+
+	lastScrapeTimestampMetric := prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: "stats",
+			Name:      "last_scrape_timestamp",
+			Help:      "Number of seconds since 1970 since last scrape of stat metrics.",
+		},
+	)
+
+	lastScrapeDurationSecondsMetric := prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespace,
+			Subsystem: "stats",
+			Name:      "last_scrape_duration_seconds",
+			Help:      "Duration of the last scrape of stats.",
+		},
+	)
+
+	return &StatCollector{
+		validMetric: validMetric,
+		expiredMetric: expiredMetric,
+		countMetric: countMetric,
+		modTimeMetric: modTimeMetric,
+		info: info,
+
+		namespace:   namespace,
+		scrapesTotalMetric:              scrapesTotalMetric,
+		scrapeErrorsTotalMetric:         scrapeErrorsTotalMetric,
+		lastScrapeErrorMetric:           lastScrapeErrorMetric,
+		lastScrapeTimestampMetric:       lastScrapeTimestampMetric,
+		lastScrapeDurationSecondsMetric: lastScrapeDurationSecondsMetric,
+	}
+}
+
+func (c *StatCollector) Collect(ch chan<- prometheus.Metric) {
+	var begun = time.Now()
+
+	c.validMetric.Set(float64(c.info.Valid))
+	c.validMetric.Collect(ch)
+
+	c.expiredMetric.Set(float64(c.info.Expired))
+	c.expiredMetric.Collect(ch)
+
+	c.countMetric.Set(float64(len(c.info.Leases)))
+	c.countMetric.Collect(ch)
+
+	c.modTimeMetric.Set(float64(c.info.ModTime.Unix()))
+	c.modTimeMetric.Collect(ch)
+
+	c.scrapeErrorsTotalMetric.Collect(ch)
+
+	c.scrapesTotalMetric.Inc()
+	c.scrapesTotalMetric.Collect(ch)
+
+	c.lastScrapeErrorMetric.Set(0)
+	c.lastScrapeErrorMetric.Collect(ch)
+
+	c.lastScrapeTimestampMetric.Set(float64(time.Now().Unix()))
+	c.lastScrapeTimestampMetric.Collect(ch)
+
+	c.lastScrapeDurationSecondsMetric.Set(time.Since(begun).Seconds())
+	c.lastScrapeDurationSecondsMetric.Collect(ch)
+}
+
+func (c *StatCollector) Describe(ch chan<- *prometheus.Desc) {
+	c.validMetric.Describe(ch)
+	c.expiredMetric.Describe(ch)
+	c.countMetric.Describe(ch)
+	c.scrapesTotalMetric.Describe(ch)
+	c.scrapeErrorsTotalMetric.Describe(ch)
+	c.lastScrapeErrorMetric.Describe(ch)
+	c.lastScrapeTimestampMetric.Describe(ch)
+	c.lastScrapeDurationSecondsMetric.Describe(ch)
+}