From 760a25b94f52cab5c74e3f66382b805895aa8214 Mon Sep 17 00:00:00 2001
From: Jimmi Dyson <jimmidyson@gmail.com>
Date: Thu, 10 Sep 2015 11:59:16 +0100
Subject: [PATCH] Add machine memory & cpu cores to prometheus metrics

---
 metrics/prometheus.go               | 22 ++++++++++++++++++++--
 metrics/prometheus_test.go          |  7 +++++++
 metrics/testdata/prometheus_metrics |  6 ++++++
 3 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/metrics/prometheus.go b/metrics/prometheus.go
index 077853a9..2e8ec06a 100644
--- a/metrics/prometheus.go
+++ b/metrics/prometheus.go
@@ -27,8 +27,10 @@ import (
 type infoProvider interface {
 	// Get information about all subcontainers of the specified container (includes self).
 	SubcontainersInfo(containerName string, query *info.ContainerInfoRequest) ([]*info.ContainerInfo, error)
-	// Get information about the machine.
+	// Get information about the version.
 	GetVersionInfo() (*info.VersionInfo, error)
+	// Get information about the machine.
+	GetMachineInfo() (*info.MachineInfo, error)
 }
 
 // metricValue describes a single metric value for a given set of label values
@@ -444,7 +446,9 @@ func NewPrometheusCollector(infoProvider infoProvider) *PrometheusCollector {
 }
 
 var (
-	versionInfoDesc = prometheus.NewDesc("cadvisor_version_info", "A metric with a constant '1' value labeled by kernel version, OS version, docker version & cadvisor version.", []string{"kernelVersion", "osVersion", "dockerVersion", "cadvisorVersion"}, nil)
+	versionInfoDesc       = prometheus.NewDesc("cadvisor_version_info", "A metric with a constant '1' value labeled by kernel version, OS version, docker version & cadvisor version.", []string{"kernelVersion", "osVersion", "dockerVersion", "cadvisorVersion"}, nil)
+	machineInfoCoresDesc  = prometheus.NewDesc("machine_cpu_cores", "Number of CPU cores on the machine.", nil, nil)
+	machineInfoMemoryDesc = prometheus.NewDesc("machine_memory_bytes", "Amount of memory installed on the machine.", nil, nil)
 )
 
 // Describe describes all the metrics ever exported by cadvisor. It
@@ -455,11 +459,14 @@ func (c *PrometheusCollector) Describe(ch chan<- *prometheus.Desc) {
 		ch <- cm.desc([]string{})
 	}
 	ch <- versionInfoDesc
+	ch <- machineInfoCoresDesc
+	ch <- machineInfoMemoryDesc
 }
 
 // Collect fetches the stats from all containers and delivers them as
 // Prometheus metrics. It implements prometheus.PrometheusCollector.
 func (c *PrometheusCollector) Collect(ch chan<- prometheus.Metric) {
+	c.collectMachineInfo(ch)
 	c.collectVersionInfo(ch)
 	c.collectContainersInfo(ch)
 	c.errors.Collect(ch)
@@ -523,6 +530,17 @@ func (c *PrometheusCollector) collectVersionInfo(ch chan<- prometheus.Metric) {
 	ch <- prometheus.MustNewConstMetric(versionInfoDesc, prometheus.GaugeValue, 1, []string{versionInfo.KernelVersion, versionInfo.ContainerOsVersion, versionInfo.DockerVersion, versionInfo.CadvisorVersion}...)
 }
 
+func (c *PrometheusCollector) collectMachineInfo(ch chan<- prometheus.Metric) {
+	machineInfo, err := c.infoProvider.GetMachineInfo()
+	if err != nil {
+		c.errors.Set(1)
+		glog.Warningf("Couldn't get machine info: %s", err)
+		return
+	}
+	ch <- prometheus.MustNewConstMetric(machineInfoCoresDesc, prometheus.GaugeValue, float64(machineInfo.NumCores))
+	ch <- prometheus.MustNewConstMetric(machineInfoMemoryDesc, prometheus.GaugeValue, float64(machineInfo.MemoryCapacity))
+}
+
 // Size after which we consider memory to be "unlimited". This is not
 // MaxInt64 due to rounding by the kernel.
 const maxMemorySize = uint64(1 << 62)
diff --git a/metrics/prometheus_test.go b/metrics/prometheus_test.go
index 8c7370be..2ca5fa81 100644
--- a/metrics/prometheus_test.go
+++ b/metrics/prometheus_test.go
@@ -38,6 +38,13 @@ func (p testSubcontainersInfoProvider) GetVersionInfo() (*info.VersionInfo, erro
 	}, nil
 }
 
+func (p testSubcontainersInfoProvider) GetMachineInfo() (*info.MachineInfo, error) {
+	return &info.MachineInfo{
+		NumCores:       4,
+		MemoryCapacity: 1024,
+	}, nil
+}
+
 func (p testSubcontainersInfoProvider) SubcontainersInfo(string, *info.ContainerInfoRequest) ([]*info.ContainerInfo, error) {
 	return []*info.ContainerInfo{
 		{
diff --git a/metrics/testdata/prometheus_metrics b/metrics/testdata/prometheus_metrics
index 9413fc20..b4d089bf 100644
--- a/metrics/testdata/prometheus_metrics
+++ b/metrics/testdata/prometheus_metrics
@@ -138,6 +138,12 @@ http_response_size_bytes{handler="prometheus",quantile="0.9"} 0
 http_response_size_bytes{handler="prometheus",quantile="0.99"} 0
 http_response_size_bytes_sum{handler="prometheus"} 0
 http_response_size_bytes_count{handler="prometheus"} 0
+# HELP machine_cpu_cores Number of CPU cores on the machine.
+# TYPE machine_cpu_cores gauge
+machine_cpu_cores 4
+# HELP machine_memory_bytes Amount of memory installed on the machine.
+# TYPE machine_memory_bytes gauge
+machine_memory_bytes 1024
 # HELP process_cpu_seconds_total Total user and system CPU time spent in seconds.
 # TYPE process_cpu_seconds_total counter
 process_cpu_seconds_total 0