Merge pull request #1488 from crosbymichael/prom-containers

Add config for exporting container metrics to prom

metrics/cgroups/blkio.go

@@ -3,6 +3,8 @@
 package cgroups
 
 import (
+	"strconv"
+
 	"github.com/containerd/cgroups"
 	metrics "github.com/docker/go-metrics"
 	"github.com/prometheus/client_golang/prometheus"
@@ -101,3 +103,14 @@ var blkioMetrics = []*metric{
 		},
 	},
 }
+
+func blkioValues(l []*cgroups.BlkIOEntry) []value {
+	var out []value
+	for _, e := range l {
+		out = append(out, value{
+			v: float64(e.Value),
+			l: []string{e.Op, e.Device, strconv.FormatUint(e.Major, 10), strconv.FormatUint(e.Minor, 10)},
+		})
+	}
+	return out
+}

metrics/cgroups/cgroups.go

@@ -15,24 +15,33 @@ import (
 	"golang.org/x/net/context"
 )
 
+type Config struct {
+	NoPrometheus bool `toml:"no_prometheus"`
+}
+
 func init() {
 	plugin.Register(&plugin.Registration{
 		Type:   plugin.TaskMonitorPlugin,
 		ID:     "cgroups",
 		Init:   New,
+		Config: &Config{},
 	})
 }
 
 func New(ic *plugin.InitContext) (interface{}, error) {
-	var (
+	var ns *metrics.Namespace
+	config := ic.Config.(*Config)
+	if !config.NoPrometheus {
 		ns = metrics.NewNamespace("container", "", nil)
-		collector = NewCollector(ns)
-	)
+	}
+	collector := NewCollector(ns)
 	oom, err := NewOOMCollector(ns)
 	if err != nil {
 		return nil, err
 	}
+	if ns != nil {
 		metrics.Register(ns)
+	}
 	return &cgroupsMonitor{
 		collector: collector,
 		oom:       oom,

metrics/cgroups/metrics.go

@@ -5,7 +5,6 @@ package cgroups
 import (
 	"errors"
 	"fmt"
-	"strconv"
 	"sync"
 
 	"github.com/containerd/cgroups"
@@ -26,6 +25,9 @@ type Trigger func(string, string, cgroups.Cgroup)
 // New registers the Collector with the provided namespace and returns it so
 // that cgroups can be added for collection
 func NewCollector(ns *metrics.Namespace) *Collector {
+	if ns == nil {
+		return &Collector{}
+	}
 	// add machine cpus and memory info
 	c := &Collector{
 		ns:      ns,
@@ -91,6 +93,9 @@ func (c *Collector) collect(id, namespace string, cg cgroups.Cgroup, ch chan<- p
 
 // Add adds the provided cgroup and id so that metrics are collected and exported
 func (c *Collector) Add(id, namespace string, cg cgroups.Cgroup) error {
+	if c.ns == nil {
+		return nil
+	}
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	if _, ok := c.cgroups[taskID(id, namespace)]; ok {
@@ -104,32 +109,12 @@ func (c *Collector) Add(id, namespace string, cg cgroups.Cgroup) error {
 	return nil
 }
 
-// Get returns the cgroup that is being collected under the provided id
-// returns ErrCgroupNotExists if the id is not being collected
-func (c *Collector) Get(id, namespace string) (cgroups.Cgroup, error) {
-	c.mu.Lock()
-	defer c.mu.Unlock()
-	t, ok := c.cgroups[taskID(id, namespace)]
-	if !ok {
-		return nil, ErrCgroupNotExists
-	}
-	return t.cgroup, nil
-}
-
 // Remove removes the provided cgroup by id from the collector
 func (c *Collector) Remove(id, namespace string) {
+	if c.ns == nil {
+		return
+	}
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	delete(c.cgroups, taskID(id, namespace))
 }
-
-func blkioValues(l []*cgroups.BlkIOEntry) []value {
-	var out []value
-	for _, e := range l {
-		out = append(out, value{
-			v: float64(e.Value),
-			l: []string{e.Op, e.Device, strconv.FormatUint(e.Major, 10), strconv.FormatUint(e.Minor, 10)},
-		})
-	}
-	return out
-}

metrics/cgroups/oom.go

@@ -19,12 +19,18 @@ func NewOOMCollector(ns *metrics.Namespace) (*OOMCollector, error) {
 	if err != nil {
 		return nil, err
 	}
+	var desc *prometheus.Desc
+	if ns != nil {
+		desc = ns.NewDesc("memory_oom", "The number of times a container has received an oom event", metrics.Total, "container_id", "namespace")
+	}
 	c := &OOMCollector{
 		fd:   fd,
-		desc: ns.NewDesc("memory_oom", "The number of times a container has received an oom event", metrics.Total, "container_id", "namespace"),
+		desc: desc,
 		set:  make(map[uintptr]*oom),
 	}
+	if ns != nil {
 		ns.Add(c)
+	}
 	go c.start()
 	return c, nil
 }