rapl_linux collector

This exposes RAPL statistics from /sys/class/powercap.

Co-Authored-By: Ben Kochie <superq@gmail.com>
Signed-off-by: Ukri Niemimuukko <ukri.niemimuukko@intel.com>

collector/rapl_linux.go

@@ -0,0 +1,77 @@
+// Copyright 2019 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 !norapl
+
+package collector
+
+import (
+	"strconv"
+
+	"github.com/go-kit/kit/log"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/procfs/sysfs"
+)
+
+type raplCollector struct {
+	fs sysfs.FS
+}
+
+func init() {
+	registerCollector("rapl", defaultEnabled, NewRaplCollector)
+}
+
+// NewRaplCollector returns a new Collector exposing RAPL metrics.
+func NewRaplCollector(logger log.Logger) (Collector, error) {
+	fs, err := sysfs.NewFS(*sysPath)
+
+	if err != nil {
+		return nil, err
+	}
+
+	collector := raplCollector{
+		fs: fs,
+	}
+	return &collector, nil
+}
+
+// Update implements Collector and exposes RAPL related metrics.
+func (c *raplCollector) Update(ch chan<- prometheus.Metric) error {
+	// nil zones are fine when platform doesn't have powercap files present.
+	zones, err := sysfs.GetRaplZones(c.fs)
+	if err != nil {
+		return nil
+	}
+
+	for _, rz := range zones {
+		newMicrojoules, err := rz.GetEnergyMicrojoules()
+		if err != nil {
+			return err
+		}
+		index := strconv.Itoa(rz.Index)
+
+		descriptor := prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "rapl", rz.Name+"_joules_total"),
+			"Current RAPL "+rz.Name+" value in joules",
+			[]string{"index"}, nil,
+		)
+
+		ch <- prometheus.MustNewConstMetric(
+			descriptor,
+			prometheus.CounterValue,
+			float64(newMicrojoules)/1000000.0,
+			index,
+		)
+	}
+	return nil
+}