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kubernetes: Add zone filtering to fallthrough (#1353)

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* Add zone filtering to fallthrough

* Doh. gofmt

* Update documentation
This commit is contained in:
John Belamaric 2018-01-06 14:52:09 -05:00 • committed by GitHub
parent 75a8a17da4
commit 84ebbbc722
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8 changed files with 95 additions and 44 deletions
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3
plugin.md
View file

@ -71,6 +71,9 @@ reverse cases and **all other** request are handled by the backing plugin. This
"fallthrough" does. To keep things explicit we've opted that plugins implement such behavior
should implement a `fallthrough` keyword.
The `fallthrough` directive should optionally accept a list of zones. Only queries for records
in one of those zones should be allowed to fallthrough.
## Qualifying for main repo
Plugins for CoreDNS can live out-of-tree, `plugin.cfg` defaults to CoreDNS' repo but other

11
plugin/kubernetes/README.md
View file

@ -38,7 +38,7 @@ kubernetes [ZONES...] {
endpoint_pod_names
upstream ADDRESS...
ttl TTL
fallthrough
fallthrough [ZONES...]
}
```
@ -85,9 +85,12 @@ kubernetes [ZONES...] {
to a file structured like resolv.conf.
* `ttl` allows you to set a custom TTL for responses. The default (and allowed minimum) is to use
5 seconds, the maximum is capped at 3600 seconds.
* `fallthrough` If a query for a record in the cluster zone results in NXDOMAIN, normally that is
what the response will be. However, if you specify this option, the query will instead be passed
on down the plugin chain, which can include another plugin to handle the query.
* `fallthrough` **[ZONES...]** If a query for a record in the zones for which the plugin is authoritative
results in NXDOMAIN, normally that is what the response will be. However, if you specify this option,
the query will instead be passed on down the plugin chain, which can include another plugin to handle
the query. If **[ZONES...]** is omitted, then fallthrough happens for all zones for which the plugin
is authoritative. If specific zones are listed (for example `in-addr.arpa` and `ip6.arpa`), then only
queries for those zones will be subject to fallthrough.
## Health

2
plugin/kubernetes/handler.go
View file

@ -59,7 +59,7 @@ func (k Kubernetes) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.M
}
if k.IsNameError(err) {
if k.Fallthrough {
if plugin.Fallthrough(k.Fallthrough, state.Name()) {
return plugin.NextOrFailure(k.Name(), k.Next, ctx, w, r)
}
return plugin.BackendError(&k, zone, dns.RcodeNameError, state, nil /* err */, plugin.Options{})

2
plugin/kubernetes/kubernetes.go
View file

@ -40,7 +40,7 @@ type Kubernetes struct {
Namespaces map[string]bool
podMode string
endpointNameMode bool
Fallthrough bool
Fallthrough *[]string // nil = disabled, empty = all zones, o/w zones
ttl uint32
primaryZoneIndex int

8
plugin/kubernetes/setup.go
View file

@ -172,12 +172,8 @@ func kubernetesParse(c *caddy.Controller) (*Kubernetes, dnsControlOpts, error) {
}
return nil, opts, c.ArgErr()
case "fallthrough":
args := c.RemainingArgs()
if len(args) == 0 {
k8s.Fallthrough = true
continue
}
return nil, opts, c.ArgErr()
zones := c.RemainingArgs()
k8s.Fallthrough = &zones
case "upstream":
args := c.RemainingArgs()
if len(args) == 0 {

76
plugin/kubernetes/setup_test.go
View file

@ -19,7 +19,7 @@ func TestKubernetesParse(t *testing.T) {
expectedResyncPeriod time.Duration // expected resync period value
expectedLabelSelector string // expected label selector value
expectedPodMode string
expectedFallthrough bool
expectedFallthrough *[]string
expectedUpstreams []string
}{
// positive
@ -32,7 +32,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -44,7 +44,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -57,7 +57,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -71,7 +71,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -85,7 +85,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -99,7 +99,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -113,7 +113,7 @@ func TestKubernetesParse(t *testing.T) {
30 * time.Second,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -127,7 +127,7 @@ func TestKubernetesParse(t *testing.T) {
15 * time.Minute,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -141,7 +141,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"environment=prod",
podModeDisabled,
false,
nil,
nil,
},
{
@ -155,7 +155,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"application=nginx,environment in (production,qa,staging)",
podModeDisabled,
false,
nil,
nil,
},
{
@ -173,7 +173,7 @@ func TestKubernetesParse(t *testing.T) {
15 * time.Minute,
"application=nginx,environment in (production,qa,staging)",
podModeDisabled,
true,
&[]string{},
nil,
},
// negative
@ -188,7 +188,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -202,7 +202,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -216,7 +216,7 @@ func TestKubernetesParse(t *testing.T) {
0 * time.Minute,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -230,7 +230,7 @@ func TestKubernetesParse(t *testing.T) {
0 * time.Second,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -244,7 +244,7 @@ func TestKubernetesParse(t *testing.T) {
0 * time.Second,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -258,7 +258,7 @@ func TestKubernetesParse(t *testing.T) {
0 * time.Second,
"",
podModeDisabled,
false,
nil,
nil,
},
{
@ -272,7 +272,7 @@ func TestKubernetesParse(t *testing.T) {
0 * time.Second,
"",
podModeDisabled,
false,
nil,
nil,
},
// pods disabled
@ -287,7 +287,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
nil,
},
// pods insecure
@ -302,7 +302,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeInsecure,
false,
nil,
nil,
},
// pods verified
@ -317,7 +317,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeVerified,
false,
nil,
nil,
},
// pods invalid
@ -332,22 +332,22 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeVerified,
false,
nil,
nil,
},
// fallthrough invalid
// fallthrough with zones
{
`kubernetes coredns.local {
fallthrough junk
fallthrough ip6.arpa inaddr.arpa foo.com
}`,
true,
false,
"rong argument count",
-1,
1,
0,
defaultResyncPeriod,
"",
podModeDisabled,
false,
&[]string{"ip6.arpa", "inaddr.arpa", "foo.com"},
nil,
},
// Valid upstream
@ -362,7 +362,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
[]string{"13.14.15.16:53"},
},
// Invalid upstream
@ -377,7 +377,7 @@ func TestKubernetesParse(t *testing.T) {
defaultResyncPeriod,
"",
podModeDisabled,
false,
nil,
nil,
},
}
@ -444,9 +444,23 @@ func TestKubernetesParse(t *testing.T) {
// fallthrough
foundFallthrough := k8sController.Fallthrough
if foundFallthrough != test.expectedFallthrough {
if foundFallthrough != nil {
failed := false
if test.expectedFallthrough == nil {
failed = true
} else if len(*foundFallthrough) != len(*test.expectedFallthrough) {
failed = true
} else {
for i := range *foundFallthrough {
if (*foundFallthrough)[i] != (*test.expectedFallthrough)[i] {
failed = true
}
}
}
if failed {
t.Errorf("Test %d: Expected kubernetes controller to be initialized with fallthrough '%v'. Instead found fallthrough '%v' for input '%s'", i, test.expectedFallthrough, foundFallthrough, test.input)
}
}
// upstream
foundUpstreams := k8sController.Proxy.Upstreams
if test.expectedUpstreams == nil {

15
plugin/plugin.go
View file

@ -83,6 +83,21 @@ func NextOrFailure(name string, next Handler, ctx context.Context, w dns.Respons
return dns.RcodeServerFailure, Error(name, errors.New("no next plugin found"))
}
// Fallthrough handles the fallthrough logic used in plugins that support it
func Fallthrough(ftzones *[]string, qname string) bool {
if ftzones == nil {
return false
}
if len(*ftzones) == 0 {
return true
}
zone := Zones(*ftzones).Matches(qname)
if zone != "" {
return true
}
return false
}
// ClientWrite returns true if the response has been written to the client.
// Each plugin to adhire to this protocol.
func ClientWrite(rcode int) bool {

20
plugin/plugin_test.go
View file

@ -1 +1,21 @@
package plugin
import "testing"
func TestFallthrough(t *testing.T) {
if Fallthrough(nil, "foo.com.") {
t.Errorf("Expected false, got true for nil fallthrough")
}
if !Fallthrough(&[]string{}, "foo.net.") {
t.Errorf("Expected true, got false for all zone fallthrough")
}
if Fallthrough(&[]string{"foo.com", "bar.com"}, "foo.net") {
t.Errorf("Expected false, got true for non-matching fallthrough zone")
}
if !Fallthrough(&[]string{"foo.com.", "bar.com."}, "bar.com.") {
t.Errorf("Expected true, got false for matching fallthrough zone")
}
}