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main.go
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main.go
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package main
import (
"context"
"encoding/json"
"fmt"
"os"
"strings"
"sync"
"time"
"github.com/alecthomas/kingpin"
foundation "github.com/estafette/estafette-foundation"
"github.com/fsnotify/fsnotify"
"github.com/rs/zerolog/log"
"github.com/ericchiang/k8s"
corev1 "github.com/ericchiang/k8s/apis/core/v1"
v1beta1 "github.com/ericchiang/k8s/apis/extensions/v1beta1"
"github.com/prometheus/client_golang/prometheus"
)
const annotationGoogleCloudDNS string = "estafette.io/google-cloud-dns"
const annotationGoogleCloudDNSHostnames string = "estafette.io/google-cloud-dns-hostnames"
const annotationGoogleCloudDNSState string = "estafette.io/google-cloud-dns-state"
// GoogleCloudDNSState represents the state of the service at Google Cloud DNS
type GoogleCloudDNSState struct {
Enabled string `json:"enabled"`
Hostnames string `json:"hostnames"`
IPAddress string `json:"ipAddress"`
}
var (
googleCloudDNSProject = kingpin.Flag("project", "The Google Cloud project id the Cloud DNS zone is configured in.").Envar("GOOGLE_CLOUD_DNS_PROJECT").Required().String()
googleCloudDNSZone = kingpin.Flag("zone", "The Google Cloud zone name to use Cloud DNS for.").Envar("GOOGLE_CLOUD_DNS_ZONE").Required().String()
appgroup string
app string
version string
branch string
revision string
buildDate string
// define prometheus counter
dnsRecordsTotals = prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "estafette_google_cloud_dns_record_totals",
Help: "Number of updated Google Cloud DNS records.",
},
[]string{"namespace", "status", "initiator", "type"},
)
)
func init() {
// Metrics have to be registered to be exposed:
prometheus.MustRegister(dnsRecordsTotals)
}
func main() {
// parse command line parameters
kingpin.Parse()
// init log format from envvar ESTAFETTE_LOG_FORMAT
foundation.InitLoggingFromEnv(foundation.NewApplicationInfo(appgroup, app, version, branch, revision, buildDate))
// init /liveness endpoint
foundation.InitLiveness()
// create kubernetes api client
kubeClient, err := k8s.NewInClusterClient()
if err != nil {
log.Fatal().Err(err).Msg("Creating Kubernetes api client failed")
}
foundation.InitMetrics()
gracefulShutdown, waitGroup := foundation.InitGracefulShutdownHandling()
// create service to Google Cloud DNS
dnsService := NewGoogleCloudDNSService(*googleCloudDNSProject, *googleCloudDNSZone)
foundation.WatchForFileChanges(os.Getenv("GOOGLE_APPLICATION_CREDENTIALS"), func(event fsnotify.Event) {
log.Info().Msg("Key file changed, reinitializing dns service...")
dnsService = NewGoogleCloudDNSService(*googleCloudDNSProject, *googleCloudDNSZone)
})
// watch services for all namespaces
go func(waitGroup *sync.WaitGroup) {
// loop indefinitely
for {
log.Info().Msg("Watching services for all namespaces...")
var service corev1.Service
watcher, err := kubeClient.Watch(context.Background(), k8s.AllNamespaces, &service, k8s.Timeout(time.Duration(300)*time.Second))
defer watcher.Close()
if err != nil {
log.Error().Err(err).Msg("WatchServices call failed")
} else {
// loop indefinitely, unless it errors
for {
service := new(corev1.Service)
event, err := watcher.Next(service)
if err != nil {
log.Error().Err(err).Msg("Getting next event from service watcher failed")
break
}
if event == k8s.EventAdded || event == k8s.EventModified {
waitGroup.Add(1)
status, err := processService(dnsService, kubeClient, service, fmt.Sprintf("watcher:%v", event))
dnsRecordsTotals.With(prometheus.Labels{"namespace": *service.Metadata.Namespace, "status": status, "initiator": "watcher", "type": "service"}).Inc()
waitGroup.Done()
if err != nil {
log.Error().Err(err).Msgf("Processing service %v.%v failed", *service.Metadata.Name, *service.Metadata.Namespace)
continue
}
}
}
}
// sleep random time between 22 and 37 seconds
sleepTime := foundation.ApplyJitter(30)
log.Info().Msgf("Sleeping for %v seconds...", sleepTime)
time.Sleep(time.Duration(sleepTime) * time.Second)
}
}(waitGroup)
// watch ingresses for all namespaces
go func(waitGroup *sync.WaitGroup) {
// loop indefinitely
for {
log.Info().Msg("Watching ingresses for all namespaces...")
var ingress v1beta1.Ingress
watcher, err := kubeClient.Watch(context.Background(), k8s.AllNamespaces, &ingress, k8s.Timeout(time.Duration(300)*time.Second))
defer watcher.Close()
if err != nil {
log.Error().Err(err).Msg("WatchIngresses call failed")
} else {
// loop indefinitely, unless it errors
for {
ingress := new(v1beta1.Ingress)
event, err := watcher.Next(ingress)
if err != nil {
log.Error().Err(err).Msg("Getting next event from ingress watcher failed")
break
}
if event == k8s.EventAdded || event == k8s.EventModified {
waitGroup.Add(1)
status, err := processIngress(dnsService, kubeClient, ingress, fmt.Sprintf("watcher:%v", event))
dnsRecordsTotals.With(prometheus.Labels{"namespace": *ingress.Metadata.Namespace, "status": status, "initiator": "watcher", "type": "ingress"}).Inc()
waitGroup.Done()
if err != nil {
log.Error().Err(err).Msgf("Processing ingress %v.%v failed", *ingress.Metadata.Name, *ingress.Metadata.Namespace)
continue
}
}
}
}
// sleep random time between 22 and 37 seconds
sleepTime := foundation.ApplyJitter(30)
log.Info().Msgf("Sleeping for %v seconds...", sleepTime)
time.Sleep(time.Duration(sleepTime) * time.Second)
}
}(waitGroup)
go func(waitGroup *sync.WaitGroup) {
// loop indefinitely
for {
// get services for all namespaces
log.Info().Msg("Listing services for all namespaces...")
var services corev1.ServiceList
err := kubeClient.List(context.Background(), k8s.AllNamespaces, &services)
if err != nil {
log.Error().Err(err).Msg("ListServices call failed")
}
log.Info().Msgf("Cluster has %v services", len(services.Items))
// loop all services
for _, service := range services.Items {
waitGroup.Add(1)
status, err := processService(dnsService, kubeClient, service, "poller")
dnsRecordsTotals.With(prometheus.Labels{"namespace": *service.Metadata.Namespace, "status": status, "initiator": "poller", "type": "service"}).Inc()
waitGroup.Done()
if err != nil {
log.Error().Err(err).Msgf("Processing service %v.%v failed", *service.Metadata.Name, *service.Metadata.Namespace)
continue
}
}
// get ingresses for all namespaces
log.Info().Msg("Listing ingresses for all namespaces...")
var ingresses v1beta1.IngressList
err = kubeClient.List(context.Background(), k8s.AllNamespaces, &ingresses)
if err != nil {
log.Error().Err(err).Msg("ListIngresses call failed")
}
log.Info().Msgf("Cluster has %v ingresses", len(ingresses.Items))
// loop all ingresses
for _, ingress := range ingresses.Items {
waitGroup.Add(1)
status, err := processIngress(dnsService, kubeClient, ingress, "poller")
dnsRecordsTotals.With(prometheus.Labels{"namespace": *ingress.Metadata.Namespace, "status": status, "initiator": "poller", "type": "ingress"}).Inc()
waitGroup.Done()
if err != nil {
log.Error().Err(err).Msgf("Processing ingress %v.%v failed", *ingress.Metadata.Name, *ingress.Metadata.Namespace)
continue
}
}
// sleep random time around 900 seconds
sleepTime := foundation.ApplyJitter(900)
log.Info().Msgf("Sleeping for %v seconds...", sleepTime)
time.Sleep(time.Duration(sleepTime) * time.Second)
}
}(waitGroup)
foundation.HandleGracefulShutdown(gracefulShutdown, waitGroup)
}
func getDesiredServiceState(service *corev1.Service) (state GoogleCloudDNSState) {
var ok bool
state.Enabled, ok = service.Metadata.Annotations[annotationGoogleCloudDNS]
if !ok {
state.Enabled = "false"
}
state.Hostnames, ok = service.Metadata.Annotations[annotationGoogleCloudDNSHostnames]
if !ok {
state.Hostnames = ""
}
if *service.Spec.Type == "LoadBalancer" && len(service.Status.LoadBalancer.Ingress) > 0 {
state.IPAddress = *service.Status.LoadBalancer.Ingress[0].Ip
}
return
}
func getCurrentServiceState(service *corev1.Service) (state GoogleCloudDNSState) {
// get state stored in annotations if present or set to empty struct
googleCloudDNSStateString, ok := service.Metadata.Annotations[annotationGoogleCloudDNSState]
if !ok {
// couldn't find saved state, setting to default struct
state = GoogleCloudDNSState{}
return
}
if err := json.Unmarshal([]byte(googleCloudDNSStateString), &state); err != nil {
// couldn't deserialize, setting to default struct
state = GoogleCloudDNSState{}
return
}
// return deserialized state
return
}
func makeServiceChanges(dnsService *GoogleCloudDNSService, client *k8s.Client, service *corev1.Service, initiator string, desiredState, currentState GoogleCloudDNSState) (status string, err error) {
status = "failed"
hasChanges := false
// check if service has estafette.io/google-cloud-dns annotation and it's value is true and
// check if service has estafette.io/google-cloud-dns-hostnames annotation and it's value is not empty and
// check if type equals LoadBalancer and
// check if LoadBalancer has an ip address
if desiredState.Enabled == "true" && len(desiredState.Hostnames) > 0 && desiredState.IPAddress != "" {
// update dns record if anything has changed compared to the stored state
if desiredState.IPAddress != currentState.IPAddress ||
desiredState.Hostnames != currentState.Hostnames {
hasChanges = true
// loop all hostnames
hostnames := strings.Split(desiredState.Hostnames, ",")
for _, hostname := range hostnames {
// validate hostname, skip if invalid
if !validateHostname(hostname) {
log.Error().Err(err).Msgf("[%v] Service %v.%v - Invalid dns record %v, skipping", initiator, *service.Metadata.Name, *service.Metadata.Namespace, hostname)
continue
}
log.Info().Msgf("[%v] Service %v.%v - Upserting dns record %v (A) to ip address %v...", initiator, *service.Metadata.Name, *service.Metadata.Namespace, hostname, desiredState.IPAddress)
err := dnsService.UpsertDNSRecord("A", hostname, desiredState.IPAddress)
if err != nil {
log.Error().Err(err).Msgf("[%v] Service %v.%v - Upserting dns record %v (A) to ip address %v failed", initiator, *service.Metadata.Name, *service.Metadata.Namespace, hostname, desiredState.IPAddress)
return status, err
}
}
}
}
if hasChanges {
// if any state property changed make sure to update all
currentState = desiredState
log.Info().Msgf("[%v] Service %v.%v - Updating service because state has changed...", initiator, *service.Metadata.Name, *service.Metadata.Namespace)
// serialize state and store it in the annotation
googleCloudDNSStateByteArray, err := json.Marshal(currentState)
if err != nil {
log.Error().Err(err).Msgf("[%v] Service %v.%v - Marshalling state failed", initiator, *service.Metadata.Name, *service.Metadata.Namespace)
return status, err
}
service.Metadata.Annotations[annotationGoogleCloudDNSState] = string(googleCloudDNSStateByteArray)
// update service, because the state annotations have changed
err = client.Update(context.Background(), service)
if err != nil {
log.Error().Err(err).Msgf("[%v] Service %v.%v - Updating service state has failed", initiator, *service.Metadata.Name, *service.Metadata.Namespace)
return status, err
}
status = "succeeded"
log.Info().Msgf("[%v] Service %v.%v - Service has been updated successfully...", initiator, *service.Metadata.Name, *service.Metadata.Namespace)
return status, nil
}
status = "skipped"
return status, nil
}
func processService(dnsService *GoogleCloudDNSService, client *k8s.Client, service *corev1.Service, initiator string) (status string, err error) {
status = "failed"
if &service != nil && &service.Metadata != nil && &service.Metadata.Annotations != nil {
desiredState := getDesiredServiceState(service)
currentState := getCurrentServiceState(service)
status, err = makeServiceChanges(dnsService, client, service, initiator, desiredState, currentState)
return
}
status = "skipped"
return status, nil
}
func getDesiredIngressState(ingress *v1beta1.Ingress) (state GoogleCloudDNSState) {
var ok bool
state.Enabled, ok = ingress.Metadata.Annotations[annotationGoogleCloudDNS]
if !ok {
state.Enabled = "false"
}
state.Hostnames, ok = ingress.Metadata.Annotations[annotationGoogleCloudDNSHostnames]
if !ok {
state.Hostnames = ""
}
if len(ingress.Status.LoadBalancer.Ingress) > 0 {
state.IPAddress = *ingress.Status.LoadBalancer.Ingress[0].Ip
}
return
}
func getCurrentIngressState(ingress *v1beta1.Ingress) (state GoogleCloudDNSState) {
// get state stored in annotations if present or set to empty struct
googleCloudDNSStateString, ok := ingress.Metadata.Annotations[annotationGoogleCloudDNSState]
if !ok {
// couldn't find saved state, setting to default struct
state = GoogleCloudDNSState{}
return
}
if err := json.Unmarshal([]byte(googleCloudDNSStateString), &state); err != nil {
// couldn't deserialize, setting to default struct
state = GoogleCloudDNSState{}
return
}
// return deserialized state
return
}
func makeIngressChanges(dnsService *GoogleCloudDNSService, client *k8s.Client, ingress *v1beta1.Ingress, initiator string, desiredState, currentState GoogleCloudDNSState) (status string, err error) {
status = "failed"
// check if ingress has estafette.io/google-cloud-dns annotation and it's value is true and
// check if ingress has estafette.io/google-cloud-dns-hostnames annotation and it's value is not empty and
// check if type equals LoadBalancer and
// check if LoadBalancer has an ip address
if desiredState.Enabled == "true" && len(desiredState.Hostnames) > 0 && desiredState.IPAddress != "" {
log.Debug().Interface("desiredState", desiredState).Interface("currentState", currentState).Msgf("[%v] Service %v.%v - Comparing current and desired state", initiator, *ingress.Metadata.Name, *ingress.Metadata.Namespace)
// update dns record if anything has changed compared to the stored state
if desiredState.IPAddress != currentState.IPAddress ||
desiredState.Hostnames != currentState.Hostnames {
// loop all hostnames
hostnames := strings.Split(desiredState.Hostnames, ",")
for _, hostname := range hostnames {
// validate hostname, skip if invalid
if !validateHostname(hostname) {
log.Error().Err(err).Msgf("[%v] Service %v.%v - Invalid dns record %v, skipping", initiator, *ingress.Metadata.Name, *ingress.Metadata.Namespace, hostname)
continue
}
log.Info().Msgf("[%v] Ingress %v.%v - Upserting dns record %v (A) to ip address %v...", initiator, *ingress.Metadata.Name, *ingress.Metadata.Namespace, hostname, desiredState.IPAddress)
err := dnsService.UpsertDNSRecord("A", hostname, desiredState.IPAddress)
if err != nil {
log.Error().Err(err).Msgf("[%v] Ingress %v.%v - Upserting dns record %v (A) to ip address %v failed", initiator, *ingress.Metadata.Name, *ingress.Metadata.Namespace, hostname, desiredState.IPAddress)
return status, err
}
}
// if any state property changed make sure to update all
currentState = desiredState
log.Info().Msgf("[%v] Ingress %v.%v - Updating ingress because state has changed...", initiator, *ingress.Metadata.Name, *ingress.Metadata.Namespace)
// serialize state and store it in the annotation
googleCloudDNSStateByteArray, err := json.Marshal(currentState)
if err != nil {
log.Error().Err(err).Msgf("[%v] Ingress %v.%v - Marshalling state failed", initiator, *ingress.Metadata.Name, *ingress.Metadata.Namespace)
return status, err
}
ingress.Metadata.Annotations[annotationGoogleCloudDNSState] = string(googleCloudDNSStateByteArray)
// update ingress, because the state annotations have changed
err = client.Update(context.Background(), ingress)
if err != nil {
log.Error().Err(err).Msgf("[%v] Ingress %v.%v - Updating ingress state has failed", initiator, *ingress.Metadata.Name, *ingress.Metadata.Namespace)
return status, err
}
status = "succeeded"
log.Info().Msgf("[%v] Ingress %v.%v - Ingress has been updated successfully...", initiator, *ingress.Metadata.Name, *ingress.Metadata.Namespace)
return status, nil
}
}
status = "skipped"
return status, nil
}
func processIngress(dnsService *GoogleCloudDNSService, client *k8s.Client, ingress *v1beta1.Ingress, initiator string) (status string, err error) {
status = "failed"
if &ingress != nil && &ingress.Metadata != nil && &ingress.Metadata.Annotations != nil {
desiredState := getDesiredIngressState(ingress)
currentState := getCurrentIngressState(ingress)
status, err = makeIngressChanges(dnsService, client, ingress, initiator, desiredState, currentState)
return
}
status = "skipped"
return status, nil
}
func validateHostname(hostname string) bool {
dnsNameParts := strings.Split(hostname, ".")
// we need at least a subdomain within a zone
if len(dnsNameParts) < 2 {
return false
}
// each label needs to be max 63 characters
for _, label := range dnsNameParts {
if len(label) > 63 {
return false
}
}
return true
}