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|
package kubernetes
import (
"errors"
"fmt"
"log"
"net"
"strings"
"time"
"github.com/coredns/coredns/core/dnsserver"
"github.com/coredns/coredns/middleware"
"github.com/coredns/coredns/middleware/pkg/dnsutil"
"github.com/coredns/coredns/middleware/proxy"
"github.com/miekg/dns"
"github.com/mholt/caddy"
unversionedapi "k8s.io/client-go/1.5/pkg/api/unversioned"
)
func init() {
caddy.RegisterPlugin("kubernetes", caddy.Plugin{
ServerType: "dns",
Action: setup,
})
}
func setup(c *caddy.Controller) error {
kubernetes, err := kubernetesParse(c)
if err != nil {
return middleware.Error("kubernetes", err)
}
err = kubernetes.InitKubeCache()
if err != nil {
return middleware.Error("kubernetes", err)
}
// Register KubeCache start and stop functions with Caddy
c.OnStartup(func() error {
go kubernetes.APIConn.Run()
if kubernetes.APIProxy != nil {
go kubernetes.APIProxy.Run()
}
return nil
})
c.OnShutdown(func() error {
if kubernetes.APIProxy != nil {
kubernetes.APIProxy.Stop()
}
return kubernetes.APIConn.Stop()
})
dnsserver.GetConfig(c).AddMiddleware(func(next middleware.Handler) middleware.Handler {
kubernetes.Next = next
return kubernetes
})
// Also register kubernetes for use in autopath.
dnsserver.GetConfig(c).RegisterHandler(kubernetes)
return nil
}
func kubernetesParse(c *caddy.Controller) (*Kubernetes, error) {
k8s := &Kubernetes{
ResyncPeriod: defaultResyncPeriod,
interfaceAddrsFunc: localPodIP,
PodMode: PodModeDisabled,
Proxy: proxy.Proxy{},
}
k8s.autoPathSearch = searchFromResolvConf()
for c.Next() {
if c.Val() == "kubernetes" {
zones := c.RemainingArgs()
if len(zones) != 0 {
k8s.Zones = zones
middleware.Zones(k8s.Zones).Normalize()
} else {
k8s.Zones = make([]string, len(c.ServerBlockKeys))
for i := 0; i < len(c.ServerBlockKeys); i++ {
k8s.Zones[i] = middleware.Host(c.ServerBlockKeys[i]).Normalize()
}
}
k8s.primaryZone = -1
for i, z := range k8s.Zones {
if strings.HasSuffix(z, "in-addr.arpa.") || strings.HasSuffix(z, "ip6.arpa.") {
continue
}
k8s.primaryZone = i
break
}
if k8s.primaryZone == -1 {
return nil, errors.New("non-reverse zone name must be given for Kubernetes")
}
for c.NextBlock() {
switch c.Val() {
case "cidrs":
// DEPRECATION WARNING
log.Printf("[WARNING] \"cidrs\" will be removed for CoreDNS soon. See https://coredns.io/2017/07/23/corefile-explained#reverse-zones for the replacement")
args := c.RemainingArgs()
if len(args) > 0 {
for _, cidrStr := range args {
_, cidr, err := net.ParseCIDR(cidrStr)
if err != nil {
return nil, fmt.Errorf("invalid cidr: %s", cidrStr)
}
k8s.ReverseCidrs = append(k8s.ReverseCidrs, *cidr)
}
continue
}
return nil, c.ArgErr()
case "pods":
args := c.RemainingArgs()
if len(args) == 1 {
switch args[0] {
case PodModeDisabled, PodModeInsecure, PodModeVerified:
k8s.PodMode = args[0]
default:
return nil, fmt.Errorf("wrong value for pods: %s, must be one of: disabled, verified, insecure", args[0])
}
continue
}
return nil, c.ArgErr()
case "namespaces":
args := c.RemainingArgs()
if len(args) > 0 {
k8s.Namespaces = append(k8s.Namespaces, args...)
continue
}
return nil, c.ArgErr()
case "endpoint":
args := c.RemainingArgs()
if len(args) > 0 {
for _, endpoint := range strings.Split(args[0], ",") {
k8s.APIServerList = append(k8s.APIServerList, strings.TrimSpace(endpoint))
}
continue
}
return nil, c.ArgErr()
case "tls": // cert key cacertfile
args := c.RemainingArgs()
if len(args) == 3 {
k8s.APIClientCert, k8s.APIClientKey, k8s.APICertAuth = args[0], args[1], args[2]
continue
}
return nil, c.ArgErr()
case "resyncperiod":
args := c.RemainingArgs()
if len(args) > 0 {
rp, err := time.ParseDuration(args[0])
if err != nil {
return nil, fmt.Errorf("unable to parse resync duration value: '%v': %v", args[0], err)
}
k8s.ResyncPeriod = rp
continue
}
return nil, c.ArgErr()
case "labels":
args := c.RemainingArgs()
if len(args) > 0 {
labelSelectorString := strings.Join(args, " ")
ls, err := unversionedapi.ParseToLabelSelector(labelSelectorString)
if err != nil {
return nil, fmt.Errorf("unable to parse label selector value: '%v': %v", labelSelectorString, err)
}
k8s.LabelSelector = ls
continue
}
return nil, c.ArgErr()
case "fallthrough":
args := c.RemainingArgs()
if len(args) == 0 {
k8s.Fallthrough = true
continue
}
return nil, c.ArgErr()
case "upstream":
args := c.RemainingArgs()
if len(args) == 0 {
return nil, c.ArgErr()
}
ups, err := dnsutil.ParseHostPortOrFile(args...)
if err != nil {
return nil, err
}
k8s.Proxy = proxy.NewLookup(ups)
case "federation": // name zone
args := c.RemainingArgs()
if len(args) == 2 {
k8s.Federations = append(k8s.Federations, Federation{
name: args[0],
zone: args[1],
})
continue
}
return nil, fmt.Errorf("incorrect number of arguments for federation, got %v, expected 2", len(args))
}
}
return k8s, nil
}
}
return nil, errors.New("kubernetes setup called without keyword 'kubernetes' in Corefile")
}
func searchFromResolvConf() []string {
rc, err := dns.ClientConfigFromFile("/etc/resolv.conf")
if err != nil {
return nil
}
middleware.Zones(rc.Search).Normalize()
return rc.Search
}
const (
defaultResyncPeriod = 5 * time.Minute
defautNdots = 0
defaultOnNXDOMAIN = dns.RcodeSuccess
)
|
