prometheus/retrieval/discovery/kubernetes_v2/pod.go

package kubernetesv2

import (
	"fmt"
	"net"
	"strconv"
	"strings"

	"github.com/prometheus/common/log"
	"github.com/prometheus/common/model"
	"github.com/prometheus/prometheus/config"
	"golang.org/x/net/context"
	"k8s.io/kubernetes/pkg/api"
	apiv1 "k8s.io/kubernetes/pkg/api/v1"
	"k8s.io/kubernetes/pkg/client/cache"
)

// Pods discovers new pod targets.
type Pod struct {
	informer cache.SharedInformer
	store    cache.Store
	logger   log.Logger
}

// NewPods creates a new pod discovery.
func NewPods(l log.Logger, pods cache.SharedInformer) *Pod {
	return &Pod{
		informer: pods,
		store:    pods.GetStore(),
		logger:   l,
	}
}

// Run implements the TargetProvider interface.
func (p *Pod) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
	// Send full initial set of pod targets.
	var initial []*config.TargetGroup
	for _, o := range p.store.List() {
		tg := p.buildPod(o.(*apiv1.Pod))
		initial = append(initial, tg)

		p.logger.With("tg", fmt.Sprintf("%#v", tg)).Debugln("initial pod")
	}
	select {
	case <-ctx.Done():
		return
	case ch <- initial:
	}

	// Send target groups for pod updates.
	send := func(tg *config.TargetGroup) {
		p.logger.With("tg", fmt.Sprintf("%#v", tg)).Debugln("pod update")
		select {
		case <-ctx.Done():
		case ch <- []*config.TargetGroup{tg}:
		}
	}
	p.informer.AddEventHandler(cache.ResourceEventHandlerFuncs{
		AddFunc: func(o interface{}) {
			send(p.buildPod(o.(*apiv1.Pod)))
		},
		DeleteFunc: func(o interface{}) {
			send(&config.TargetGroup{Source: podSource(o.(*apiv1.Pod))})
		},
		UpdateFunc: func(_, o interface{}) {
			send(p.buildPod(o.(*apiv1.Pod)))
		},
	})

	// Block until the target provider is explicitly canceled.
	<-ctx.Done()
}

const (
	podNameLabel                  = metaLabelPrefix + "pod_name"
	podAddressLabel               = metaLabelPrefix + "pod_address"
	podContainerNameLabel         = metaLabelPrefix + "pod_container_name"
	podContainerPortNameLabel     = metaLabelPrefix + "pod_container_port_name"
	podContainerPortProtocolLabel = metaLabelPrefix + "pod_container_port_protocol"
	podReadyLabel                 = metaLabelPrefix + "pod_ready"
	podLabelPrefix                = metaLabelPrefix + "pod_label_"
	podAnnotationPrefix           = metaLabelPrefix + "pod_annotation_"
	podNodeNameLabel              = metaLabelPrefix + "pod_node_name"
	podHostIPLabel                = metaLabelPrefix + "pod_host_ip"
)

func (p *Pod) buildPod(pod *apiv1.Pod) *config.TargetGroup {
	tg := &config.TargetGroup{
		Source: podSource(pod),
	}
	tg.Labels = model.LabelSet{
		namespaceLabel:   lv(pod.Namespace),
		podNameLabel:     lv(pod.ObjectMeta.Name),
		podAddressLabel:  lv(pod.Status.PodIP),
		podReadyLabel:    podReady(pod),
		podNodeNameLabel: lv(pod.Spec.NodeName),
		podHostIPLabel:   lv(pod.Status.HostIP),
	}

	for _, c := range pod.Spec.Containers {
		// If no ports are defined for the container, create an anonymous
		// target per container.
		if len(c.Ports) == 0 {
			// We don't have a port so we just set the address label to the pod IP.
			// The user has to add a port manually.
			tg.Targets = append(tg.Targets, model.LabelSet{
				model.AddressLabel:    lv(pod.Status.PodIP),
				podContainerNameLabel: lv(c.Name),
			})
			continue
		}
		// Otherwise create one target for each container/port combination.
		for _, port := range c.Ports {
			addr := net.JoinHostPort(pod.Status.PodIP, strconv.FormatInt(int64(port.ContainerPort), 10))

			tg.Targets = append(tg.Targets, model.LabelSet{
				model.AddressLabel:            lv(addr),
				podContainerNameLabel:         lv(c.Name),
				podContainerPortNameLabel:     lv(port.Name),
				podContainerPortProtocolLabel: lv(string(port.Protocol)),
			})
		}
	}

	return tg
}

func podSource(pod *apiv1.Pod) string {
	return "pod/" + pod.Namespace + "/" + pod.Name
}

func podReady(pod *apiv1.Pod) model.LabelValue {
	for _, cond := range pod.Status.Conditions {
		if cond.Type == apiv1.PodReady {
			return lv(strings.ToLower(string(cond.Status)))
		}
	}
	return lv(strings.ToLower(string(api.ConditionUnknown)))
}