internal/pkg/composable/providers/kubernetes/pod.go

// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
// or more contributor license agreements. Licensed under the Elastic License 2.0;
// you may not use this file except in compliance with the Elastic License 2.0.

package kubernetes

import (
	"fmt"
	"sync"
	"time"

	v1 "k8s.io/api/core/v1"

	"k8s.io/apimachinery/pkg/runtime/schema"

	"github.com/elastic/elastic-agent-autodiscover/kubernetes"
	"github.com/elastic/elastic-agent-autodiscover/kubernetes/metadata"
	"github.com/elastic/elastic-agent-autodiscover/utils"
	c "github.com/elastic/elastic-agent-libs/config"
	"github.com/elastic/elastic-agent-libs/logp"
	"github.com/elastic/elastic-agent-libs/mapstr"
	"github.com/elastic/elastic-agent-libs/safemapstr"

	k8s "k8s.io/client-go/kubernetes"

	"github.com/elastic/elastic-agent/internal/pkg/agent/errors"
	"github.com/elastic/elastic-agent/internal/pkg/composable"
)

type pod struct {
	watcher           kubernetes.Watcher
	nodeWatcher       kubernetes.Watcher
	comm              composable.DynamicProviderComm
	metagen           metadata.MetaGen
	namespaceWatcher  kubernetes.Watcher
	replicasetWatcher kubernetes.Watcher
	jobWatcher        kubernetes.Watcher
	config            *Config
	logger            *logp.Logger
	scope             string
	managed           bool
	cleanupTimeout    time.Duration

	// Mutex used by configuration updates not triggered by the main watcher,
	// to avoid race conditions between cross updates and deletions.
	// Other updaters must use a write lock.
	crossUpdate sync.RWMutex
}

type providerData struct {
	uid        string
	mapping    map[string]interface{}
	processors []map[string]interface{}
}

// hintsData hold the generated mapping data needed for hints based autodsicovery
type hintsData struct {
	composableMapping mapstr.M
	processors        []mapstr.M
}

// NewPodEventer creates an eventer that can discover and process pod objects
func NewPodEventer(
	comm composable.DynamicProviderComm,
	cfg *Config,
	logger *logp.Logger,
	client k8s.Interface,
	scope string,
	managed bool) (Eventer, error) {
	watcher, err := kubernetes.NewNamedWatcher("agent-pod", client, &kubernetes.Pod{}, kubernetes.WatchOptions{
		SyncTimeout:  cfg.SyncPeriod,
		Node:         cfg.Node,
		Namespace:    cfg.Namespace,
		HonorReSyncs: true,
	}, nil)
	if err != nil {
		return nil, errors.New(err, "couldn't create kubernetes watcher")
	}

	var replicaSetWatcher, jobWatcher, namespaceWatcher, nodeWatcher kubernetes.Watcher

	metaConf := cfg.AddResourceMetadata

	if metaConf.Node.Enabled() || cfg.Hints.Enabled {
		nodeWatcher, err = kubernetes.NewNamedWatcher("agent-node", client, &kubernetes.Node{}, kubernetes.WatchOptions{
			SyncTimeout:  cfg.SyncPeriod,
			Node:         cfg.Node,
			HonorReSyncs: true,
		}, nil)
		if err != nil {
			logger.Errorf("couldn't create watcher for %T due to error %+v", &kubernetes.Node{}, err)
		}
	}

	if metaConf.Namespace.Enabled() || cfg.Hints.Enabled {
		namespaceWatcher, err = kubernetes.NewNamedWatcher("agent-namespace", client, &kubernetes.Namespace{}, kubernetes.WatchOptions{
			SyncTimeout:  cfg.SyncPeriod,
			Namespace:    cfg.Namespace,
			HonorReSyncs: true,
		}, nil)
		if err != nil {
			logger.Errorf("couldn't create watcher for %T due to error %+v", &kubernetes.Namespace{}, err)
		}
	}

	// Resource is Pod, so we need to create watchers for Replicasets and Jobs that it might belong to
	// in order to be able to retrieve 2nd layer Owner metadata like in case of:
	// Deployment -> Replicaset -> Pod
	// CronJob -> job -> Pod
	if metaConf.Deployment {
		metadataClient, err := kubernetes.GetKubernetesMetadataClient(cfg.KubeConfig, cfg.KubeClientOptions)
		if err != nil {
			logger.Errorf("Error creating metadata client for %T due to error %+v", &kubernetes.Namespace{}, err)
		}
		// use a custom watcher here, so we can provide a transform function and limit the data we're storing
		replicaSetWatcher, err = kubernetes.NewNamedMetadataWatcher(
			"resource_metadata_enricher_rs",
			client,
			metadataClient,
			schema.GroupVersionResource{Group: "apps", Version: "v1", Resource: "replicasets"},
			kubernetes.WatchOptions{
				SyncTimeout:  cfg.SyncPeriod,
				Namespace:    cfg.Namespace,
				HonorReSyncs: true,
			}, nil, metadata.RemoveUnnecessaryReplicaSetData)
		if err != nil {
			logger.Errorf("Error creating watcher for %T due to error %+v", &kubernetes.Namespace{}, err)
		}
	}
	if metaConf.CronJob {
		jobWatcher, err = kubernetes.NewNamedWatcher("resource_metadata_enricher_job", client, &kubernetes.Job{}, kubernetes.WatchOptions{
			SyncTimeout:  cfg.SyncPeriod,
			Namespace:    cfg.Namespace,
			HonorReSyncs: true,
		}, nil)
		if err != nil {
			logger.Errorf("Error creating watcher for %T due to error %+v", &kubernetes.Job{}, err)
		}
	}

	rawConfig, err := c.NewConfigFrom(cfg)
	if err != nil {
		return nil, errors.New(err, "failed to unpack configuration")
	}
	metaGen := metadata.GetPodMetaGen(rawConfig, watcher, nodeWatcher, namespaceWatcher, replicaSetWatcher, jobWatcher, metaConf)

	p := &pod{
		logger:            logger,
		cleanupTimeout:    cfg.CleanupTimeout,
		comm:              comm,
		scope:             scope,
		config:            cfg,
		metagen:           metaGen,
		watcher:           watcher,
		nodeWatcher:       nodeWatcher,
		namespaceWatcher:  namespaceWatcher,
		replicasetWatcher: replicaSetWatcher,
		jobWatcher:        jobWatcher,
		managed:           managed,
	}

	watcher.AddEventHandler(p)

	if nodeWatcher != nil && metaConf.Node.Enabled() {
		updater := kubernetes.NewNodePodUpdater(p.unlockedUpdate, watcher.Store(), p.nodeWatcher, &p.crossUpdate)
		nodeWatcher.AddEventHandler(updater)
	}

	if namespaceWatcher != nil && metaConf.Namespace.Enabled() {
		updater := kubernetes.NewNamespacePodUpdater(p.unlockedUpdate, watcher.Store(), p.namespaceWatcher, &p.crossUpdate)
		namespaceWatcher.AddEventHandler(updater)
	}

	return p, nil
}

// Start starts the eventer
func (p *pod) Start() error {
	if p.nodeWatcher != nil {
		err := p.nodeWatcher.Start()
		if err != nil {
			return err
		}
	}

	if p.namespaceWatcher != nil {
		if err := p.namespaceWatcher.Start(); err != nil {
			return err
		}
	}

	if p.replicasetWatcher != nil {
		if err := p.replicasetWatcher.Start(); err != nil {
			return err
		}
	}

	if p.jobWatcher != nil {
		if err := p.jobWatcher.Start(); err != nil {
			return err
		}
	}

	return p.watcher.Start()
}

// Stop stops the eventer
func (p *pod) Stop() {
	p.watcher.Stop()

	if p.namespaceWatcher != nil {
		p.namespaceWatcher.Stop()
	}

	if p.nodeWatcher != nil {
		p.nodeWatcher.Stop()
	}

	if p.replicasetWatcher != nil {
		p.replicasetWatcher.Stop()
	}

	if p.jobWatcher != nil {
		p.jobWatcher.Stop()
	}
}

func (p *pod) emitRunning(pod *kubernetes.Pod) {
	if pod.Status.Phase == v1.PodPending || pod.Status.Phase == v1.PodUnknown {
		return
	}
	namespaceAnnotations := kubernetes.PodNamespaceAnnotations(pod, p.namespaceWatcher)

	data := generatePodData(pod, p.metagen, namespaceAnnotations)
	data.mapping["scope"] = p.scope

	if p.config.Hints.Enabled { // This is "hints based autodiscovery flow"
		if !p.managed {
			if ann, ok := data.mapping["annotations"]; ok {
				annotations, _ := ann.(mapstr.M)
				hints, _ := hintsCheck(annotations, "", p.config.Prefix, true, allSupportedHints, p.logger, pod)
				if len(hints) > 0 {
					p.logger.Debugf("Extracted hints are :%v", hints)
					hintsMapping := GenerateHintsMapping(hints, data.mapping, p.logger, "")
					p.logger.Debugf("Generated Pods' hints mappings are :%v", hintsMapping)
					_ = p.comm.AddOrUpdate(
						data.uid,
						PodPriority,
						map[string]interface{}{"hints": hintsMapping},
						data.processors,
					)
				}
			}
		}
	} else { // This is the "template-based autodiscovery" flow
		// emit normal mapping to be used in dynamic variable resolution
		// Emit the pod
		// We emit Pod + containers to ensure that configs matching Pod only
		// get Pod metadata (not specific to any container)
		_ = p.comm.AddOrUpdate(data.uid, PodPriority, data.mapping, data.processors)
	}

	// Emit all containers in the pod
	// We should deal with init containers stopping after initialization
	p.emitContainers(pod, namespaceAnnotations)
}

func (p *pod) emitContainers(pod *kubernetes.Pod, namespaceAnnotations mapstr.M) {
	generateContainerData(p.comm, pod, p.metagen, namespaceAnnotations, p.logger, p.managed, p.config)
}

func (p *pod) emitStopped(pod *kubernetes.Pod) {
	p.comm.Remove(string(pod.GetUID()))

	for _, c := range pod.Spec.Containers {
		// ID is the combination of pod UID + container name
		eventID := fmt.Sprintf("%s.%s", pod.GetObjectMeta().GetUID(), c.Name)
		p.comm.Remove(eventID)
	}

	for _, c := range pod.Spec.InitContainers {
		// ID is the combination of pod UID + container name
		eventID := fmt.Sprintf("%s.%s", pod.GetObjectMeta().GetUID(), c.Name)
		p.comm.Remove(eventID)
	}
}

// OnAdd ensures processing of pod objects that are newly added
func (p *pod) OnAdd(obj interface{}) {
	p.crossUpdate.RLock()
	defer p.crossUpdate.RUnlock()

	p.logger.Debugf("pod add: %+v", obj)
	p.emitRunning(obj.(*kubernetes.Pod))
}

// OnUpdate emits events for a given pod depending on the state of the pod,
// if it is terminating, a stop event is scheduled, if not, a stop and a start
// events are sent sequentially to recreate the resources assotiated to the pod.
func (p *pod) OnUpdate(obj interface{}) {
	p.crossUpdate.RLock()
	defer p.crossUpdate.RUnlock()

	p.unlockedUpdate(obj)
}

func (p *pod) unlockedUpdate(obj interface{}) {
	p.logger.Debugf("Watcher Pod update: %+v", obj)
	pod, _ := obj.(*kubernetes.Pod)
	p.emitRunning(pod)
}

// OnDelete stops pod objects that are deleted
func (p *pod) OnDelete(obj interface{}) {
	p.crossUpdate.RLock()
	defer p.crossUpdate.RUnlock()

	p.logger.Debugf("pod delete: %+v", obj)
	pod, _ := obj.(*kubernetes.Pod)
	time.AfterFunc(p.cleanupTimeout, func() {
		p.emitStopped(pod)
	})
}

func generatePodData(
	pod *kubernetes.Pod,
	kubeMetaGen metadata.MetaGen,
	namespaceAnnotations mapstr.M) providerData {

	meta := kubeMetaGen.Generate(pod)
	kubemetaMap, err := meta.GetValue("kubernetes")
	if err != nil {
		return providerData{}
	}

	// k8sMapping includes only the metadata that fall under kubernetes.*
	// and these are available as dynamic vars through the provider
	k8sMapping := map[string]interface{}(kubemetaMap.(mapstr.M).Clone())

	if len(namespaceAnnotations) != 0 {
		k8sMapping["namespace_annotations"] = namespaceAnnotations
	}
	// Pass annotations to all events so that it can be used in templating and by annotation builders.
	annotations := mapstr.M{}
	for k, v := range pod.GetObjectMeta().GetAnnotations() {
		_ = safemapstr.Put(annotations, k, v)
	}
	k8sMapping["annotations"] = annotations
	// Pass labels(not dedoted) to all events so that they can be used in templating.
	labels := mapstr.M{}
	for k, v := range pod.GetObjectMeta().GetLabels() {
		_ = safemapstr.Put(labels, k, v)
	}
	k8sMapping["labels"] = labels

	processors := []map[string]interface{}{}
	// meta map includes metadata that go under kubernetes.*
	// but also other ECS fields like orchestrator.*
	for field, metaMap := range meta {
		processor := map[string]interface{}{
			"add_fields": map[string]interface{}{
				"fields": metaMap,
				"target": field,
			},
		}
		processors = append(processors, processor)
	}

	return providerData{
		uid:        string(pod.GetUID()),
		mapping:    k8sMapping,
		processors: processors,
	}
}

func generateContainerData(
	comm composable.DynamicProviderComm,
	pod *kubernetes.Pod,
	kubeMetaGen metadata.MetaGen,
	namespaceAnnotations mapstr.M,
	logger *logp.Logger,
	managed bool,
	config *Config) {

	containers := kubernetes.GetContainersInPod(pod)

	// Pass annotations to all events so that it can be used in templating and by annotation builders.
	annotations := mapstr.M{}
	for k, v := range pod.GetObjectMeta().GetAnnotations() {
		_ = safemapstr.Put(annotations, k, v)
	}

	// Pass labels to all events so that it can be used in templating.
	labels := mapstr.M{}
	for k, v := range pod.GetObjectMeta().GetLabels() {
		_ = safemapstr.Put(labels, k, v)
	}

	for _, c := range containers {
		// If it doesn't have an ID, container doesn't exist in
		// the runtime, emit only an event if we are stopping, so
		// we are sure of cleaning up configurations.
		if c.ID == "" {
			continue
		}

		// ID is the combination of pod UID + container name
		eventID := fmt.Sprintf("%s.%s", pod.GetObjectMeta().GetUID(), c.Spec.Name)

		meta := kubeMetaGen.Generate(pod, metadata.WithFields("container.name", c.Spec.Name))
		kubemetaMap, err := meta.GetValue("kubernetes")
		if err != nil {
			continue
		}

		// k8sMapping includes only the metadata that fall under kubernetes.*
		// and these are available as dynamic vars through the provider
		k8sMapping := map[string]interface{}(kubemetaMap.(mapstr.M).Clone())

		if len(namespaceAnnotations) != 0 {
			k8sMapping["namespace_annotations"] = namespaceAnnotations
		}
		// add annotations and labels to be discoverable by templates
		k8sMapping["annotations"] = annotations
		k8sMapping["labels"] = labels

		//container ECS fields
		cmeta := mapstr.M{
			"id":      c.ID,
			"runtime": c.Runtime,
			"image": mapstr.M{
				"name": c.Spec.Image,
			},
		}

		processors := []map[string]interface{}{
			{
				"add_fields": map[string]interface{}{
					"fields": cmeta,
					"target": "container",
				},
			},
		}
		// meta map includes metadata that go under kubernetes.*
		// but also other ECS fields like orchestrator.*
		for field, metaMap := range meta {
			processor := map[string]interface{}{
				"add_fields": map[string]interface{}{
					"fields": metaMap,
					"target": field,
				},
			}
			processors = append(processors, processor)
		}

		// add container metadata under kubernetes.container.* to
		// make them available to dynamic var resolution

		containerMeta := mapstr.M{
			"id":      c.ID,
			"name":    c.Spec.Name,
			"image":   c.Spec.Image,
			"runtime": c.Runtime,
		}

		if len(c.Spec.Ports) > 0 {
			for _, port := range c.Spec.Ports {
				_, _ = containerMeta.Put("port", fmt.Sprintf("%v", port.ContainerPort))
				_, _ = containerMeta.Put("port_name", port.Name)
				k8sMapping["container"] = containerMeta

				if config.Hints.Enabled { // This is "hints based autodiscovery flow"
					if !managed {
						hintData := GetHintsMapping(k8sMapping, logger, config.Prefix, c.ID)
						if len(hintData.composableMapping) > 0 {
							if len(hintData.processors) > 0 {
								processors = updateProcessors(hintData.processors, processors)
							}
							_ = comm.AddOrUpdate(
								eventID,
								PodPriority,
								map[string]interface{}{"hints": hintData.composableMapping},
								processors,
							)
						} else if config.Hints.DefaultContainerLogs {
							// in case of no package detected in the hints fallback to the generic log collection
							_, _ = hintData.composableMapping.Put("container_logs.enabled", true)
							_, _ = hintData.composableMapping.Put("container_id", c.ID)
							if len(hintData.processors) > 0 {
								processors = updateProcessors(hintData.processors, processors)
							}
							_ = comm.AddOrUpdate(
								eventID,
								PodPriority,
								map[string]interface{}{"hints": hintData.composableMapping},
								processors,
							)
						}
					}
				} else { // This is the "template-based autodiscovery" flow
					_ = comm.AddOrUpdate(eventID, ContainerPriority, k8sMapping, processors)
				}
			}
		} else {
			k8sMapping["container"] = containerMeta
			if config.Hints.Enabled { // This is "hints based autodiscovery flow"
				if !managed {
					hintData := GetHintsMapping(k8sMapping, logger, config.Prefix, c.ID)
					if len(hintData.composableMapping) > 0 {
						if len(hintData.processors) > 0 {
							processors = updateProcessors(hintData.processors, processors)
						}
						_ = comm.AddOrUpdate(
							eventID,
							PodPriority,
							map[string]interface{}{"hints": hintData.composableMapping},
							processors,
						)
					} else if config.Hints.DefaultContainerLogs {
						// in case of no package detected in the hints fallback to the generic log collection
						_, _ = hintData.composableMapping.Put("container_logs.enabled", true)
						_, _ = hintData.composableMapping.Put("container_id", c.ID)
						if len(hintData.processors) > 0 {
							processors = updateProcessors(hintData.processors, processors)
						}
						_ = comm.AddOrUpdate(
							eventID,
							PodPriority,
							map[string]interface{}{"hints": hintData.composableMapping},
							processors,
						)
					}
				}
			} else { // This is the "template-based autodiscovery" flow
				_ = comm.AddOrUpdate(eventID, ContainerPriority, k8sMapping, processors)
			}
		}
	}
}

// Updates processors map with any additional processors identfied from annotations
func updateProcessors(newprocessors []mapstr.M, processors []map[string]interface{}) []map[string]interface{} {
	for _, processor := range newprocessors {
		processors = append(processors, processor)
	}

	return processors
}

// HintsCheck geenrates hints from provided annotations of the pod and logs any possible incorrect annotations that have been provided in the pod
func hintsCheck(annotations mapstr.M, container string, prefix string, validate bool, allSupportedHints []string, logger *logp.Logger, pod *kubernetes.Pod) (mapstr.M, []string) {
	hints, incorrecthints := utils.GenerateHints(annotations, container, prefix, validate, allSupportedHints)
	for _, value := range incorrecthints { //We check whether the provided annotation follows the supported format and vocabulary. The check happens for annotations that have prefix co.elastic
		logger.Warnf("provided hint: %s/%s is not recognised as supported annotation for pod %s in namespace %s", prefix, value, pod.Name, pod.ObjectMeta.Namespace)
	}
	return hints, incorrecthints
}