collector: implement node_boot_time_seconds for OpenBSD/NetBSD/Darwin

Signed-off-by: mischief <mischief@offblast.org>

collector/boot_time_bsd.go

@@ -0,0 +1,56 @@
+// Copyright 2018 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.
+
+// +build freebsd dragonfly openbsd netbsd darwin
+// +build !noboottime
+
+package collector
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type bootTimeCollector struct{ boottime bsdSysctl }
+
+func init() {
+	registerCollector("boottime", defaultEnabled, newBootTimeCollector)
+}
+
+// newBootTimeCollector returns a new Collector exposing system boot time on BSD systems.
+func newBootTimeCollector() (Collector, error) {
+	return &bootTimeCollector{
+		boottime: bsdSysctl{
+			name:        "boot_time_seconds",
+			description: "Unix time of last boot, including microseconds.",
+			mib:         "kern.boottime",
+			dataType:    bsdSysctlTypeStructTimeval,
+		},
+	}, nil
+}
+
+// Update pushes boot time onto ch
+func (c *bootTimeCollector) Update(ch chan<- prometheus.Metric) error {
+	v, err := c.boottime.Value()
+	if err != nil {
+		return err
+	}
+
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "", c.boottime.name),
+			c.boottime.description,
+			nil, nil,
+		), prometheus.GaugeValue, v)
+
+	return nil
+}

collector/exec_bsd.go

@@ -39,9 +39,6 @@ func NewExecCollector() (Collector, error) {
 	// vm.stats.sys.v_intr: Device interrupts
 	// vm.stats.sys.v_soft: Software interrupts
 	// vm.stats.vm.v_forks: Number of fork() calls
-	//
-	// From sys/kern/kern_tc.c:
-	// kern.boottime is an S,timeval
 
 	return &execCollector{
 		sysctls: []bsdSysctl{
@@ -75,12 +72,6 @@ func NewExecCollector() (Collector, error) {
 				description: "Number of fork() calls since system boot.  Resets at architecture unsigned integer.",
 				mib:         "vm.stats.vm.v_forks",
 			},
-			{
-				name:        "boot_time_seconds",
-				description: "Unix time of last boot, including microseconds.",
-				mib:         "kern.boottime",
-				dataType:    bsdSysctlTypeStructTimeval,
-			},
 		},
 	}, nil
 }

collector/sysctl_bsd.go

@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build freebsd dragonfly
+// +build freebsd dragonfly openbsd netbsd darwin
 // +build !nomeminfo
 
 package collector