add sensors to the about page

sensors.go

@@ -0,0 +1,43 @@
+//
+// Copyright (c) 2019 Ted Unangst <tedu@tedunangst.com>
+//
+// Permission to use, copy, modify, and distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+package main
+
+import (
+	"syscall"
+	"time"
+)
+
+type Sensors struct {
+	Memory float64
+	Uptime float64
+	CPU    float64
+}
+
+var boottime = time.Now()
+
+func getSensors() Sensors {
+	var usage syscall.Rusage
+	syscall.Getrusage(syscall.RUSAGE_SELF, &usage)
+
+	now := time.Now()
+
+	var sensors Sensors
+	sensors.Memory = float64(usage.Maxrss) / 1024.0
+	sensors.Uptime = now.Sub(boottime).Seconds()
+	sensors.CPU = time.Duration(usage.Utime.Nano()).Seconds()
+
+	return sensors
+}

views/about.html

@@ -2,6 +2,10 @@
 <main>
 <div class="info">
 {{ .AboutMsg }}
-<p style="text-align:right"><small>version: {{ .HonkVersion }}</small>
+<p><small>version: {{ .HonkVersion }}
+<br>memory: {{ printf "%.02f" .Sensors.Memory }}MB
+<br>uptime: {{ printf "%.02f" .Sensors.Uptime }}s
+<br>cputime: {{ printf "%.02f" .Sensors.CPU }}s
+</small>
 </div>
 </main>

web.go

@@ -1902,6 +1902,9 @@ func servehtml(w http.ResponseWriter, r *http.Request) {
 	templinfo["AboutMsg"] = aboutMsg
 	templinfo["LoginMsg"] = loginMsg
 	templinfo["HonkVersion"] = honkVersion
+	if r.URL.Path == "/about" {
+		templinfo["Sensors"] = getSensors()
+	}
 	if u == nil {
 		w.Header().Set("Cache-Control", "max-age=60")
 	}