Correctly cast Darwin memory info (#1060)

* Correctly cast Darwin memory info

* Cast stats to float64 before doing math on them to avoid integer
wrapping.
* Remove invalid `_total` suffix from gauge values.
* Handle counters in `meminfo.go`.

Signed-off-by: Ben Kochie <superq@gmail.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/collector/meminfo.go b/collector/meminfo.go
index ffe343a..1652b8b 100644
--- a/collector/meminfo.go
+++ b/collector/meminfo.go
@@ -18,6 +18,7 @@ package collector
 
 import (
         "fmt"
+        "strings"
 
         "github.com/prometheus/client_golang/prometheus"
         "github.com/prometheus/common/log"
@@ -41,19 +42,25 @@ func NewMeminfoCollector() (Collector, error) {
 // Update calls (*meminfoCollector).getMemInfo to get the platform specific
 // memory metrics.
 func (c *meminfoCollector) Update(ch chan<- prometheus.Metric) error {
+        var metricType prometheus.ValueType
         memInfo, err := c.getMemInfo()
         if err != nil {
                 return fmt.Errorf("couldn't get meminfo: %s", err)
         }
         log.Debugf("Set node_mem: %#v", memInfo)
         for k, v := range memInfo {
+                if strings.HasSuffix(k, "_total") {
+                        metricType = prometheus.CounterValue
+                } else {
+                        metricType = prometheus.GaugeValue
+                }
                 ch <- prometheus.MustNewConstMetric(
                         prometheus.NewDesc(
                                 prometheus.BuildFQName(namespace, memInfoSubsystem, k),
                                 fmt.Sprintf("Memory information field %s.", k),
                                 nil, nil,
                         ),
-                        prometheus.GaugeValue, v,
+                        metricType, v,
                 )
         }
         return nil