Export GPU temperature

collector/cpu.go

@@ -17,16 +17,13 @@ import (
 	"bytes"
 	"io/ioutil"
 	"strconv"
-	"sync"
 
 	"github.com/prometheus/client_golang/prometheus"
 )
 
 const cpuSubsystem = "cpu"
 
-type cpuCollector struct {
-	mutex sync.Mutex
-}
+type cpuCollector struct{}
 
 func init() {
 	registerCollector("cpu", defaultEnabled, NewCPUCollector)
@@ -40,7 +37,7 @@ func NewCPUCollector() (Collector, error) {
 // Update implements the Collector interface.
 func (c *cpuCollector) Update(ch chan<- prometheus.Metric) error {
 	// Get temperature string from /sys/class/thermal/thermal_zone*/temp and
-	// convert it to 64bit float value.
+	// convert it to float64 value.
 	b, err := ioutil.ReadFile("/sys/class/thermal/thermal_zone0/temp")
 	if err != nil {
 		return err

collector/gpu.go

@@ -0,0 +1,65 @@
+// Copyright 2019 Lukas Malkmus
+// 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.
+
+package collector
+
+import (
+	"os/exec"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const gpuSubsystem = "gpu"
+
+type gpuCollector struct{}
+
+func init() {
+	registerCollector("gpu", defaultEnabled, NewGPUCollector)
+}
+
+// NewGPUCollector returns a new Collector exposing GPU temperature metrics.
+func NewGPUCollector() (Collector, error) {
+	return &gpuCollector{}, nil
+}
+
+// Update implements the Collector interface.
+func (c *gpuCollector) Update(ch chan<- prometheus.Metric) error {
+	// Get temperature string by executing /opt/vc/bin/vcgencmd measure_temp
+	// and convert it to float64 value.
+	cmd := exec.Command("/opt/vc/bin/vcgencmd", "measure_temp")
+	stdout, err := cmd.Output()
+	if err != nil {
+		return err
+	}
+
+	// temp=55.3'C => 55.3
+	tempStr := strings.TrimPrefix(string(stdout), "temp=")
+	tempStr = strings.TrimSuffix(tempStr, "'C\n")
+	temp, err := strconv.ParseFloat(tempStr, 64)
+	if err != nil {
+		return err
+	}
+
+	// Export the metric.
+	ch <- prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, gpuSubsystem, "temperature_celsius"),
+			"GPU temperature in degrees celsius (°C).",
+			nil, nil,
+		),
+		prometheus.GaugeValue, temp,
+	)
+	return nil
+}