plugin/template: small tweaks (#1366)

Small README updates, and fallthrough fixes (using less code)

5 files changed, 46 insertions, 51 deletions

diff --git a/plugin/template/README.md b/plugin/template/README.md
index c951cac83..13e6137b4 100644
--- a/plugin/template/README.md
+++ b/plugin/template/README.md
@@ -15,8 +15,8 @@ template CLASS TYPE [ZONE...] {
     [additional RR]
     [authority RR]
     [...]
-    [rcode responsecode]
-    [fallthrough [fallthrough zone...]]
+    [rcode CODE]
+    [fallthrough [ZONE...]]
 }
 ~~~
 
@@ -28,7 +28,8 @@ template CLASS TYPE [ZONE...] {
   build by a [Go template](https://golang.org/pkg/text/template/) that contains the reply.
 * `rcode` **CODE** A response code (`NXDOMAIN, SERVFAIL, ...`). The default is `SUCCESS`.
 * `fallthrough` Continue with the next plugin if the zone matched but no regex did not match.
-* `fallthrough zone` One or more zones that may fall through to other plugins. Defaults to all zones of the template.
+  If specific zones are listed (for example `in-addr.arpa` and `ip6.arpa`), then only queries for
+  those zones will be subject to fallthrough.
 
 At least one `answer` or `rcode` directive is needed (e.g. `rcode NXDOMAIN`).
 
diff --git a/plugin/template/metrics.go b/plugin/template/metrics.go
index a963b3a31..4cdaa5321 100644
--- a/plugin/template/metrics.go
+++ b/plugin/template/metrics.go
@@ -6,8 +6,8 @@ import (
 	"github.com/coredns/coredns/core/dnsserver"
 	"github.com/coredns/coredns/plugin"
 	"github.com/coredns/coredns/plugin/metrics"
-	"github.com/mholt/caddy"
 
+	"github.com/mholt/caddy"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
diff --git a/plugin/template/setup.go b/plugin/template/setup.go
index 2065ef649..616531e49 100644
--- a/plugin/template/setup.go
+++ b/plugin/template/setup.go
@@ -140,12 +140,7 @@ func templateParse(c *caddy.Controller) (handler Handler, err error) {
 				t.rcode = rcode
 
 			case "fallthrough":
-				args := c.RemainingArgs()
-				if len(args) > 0 {
-					t.fthrough.SetZonesFromArgs(c.RemainingArgs())
-				} else {
-					t.fthrough.SetZonesFromArgs(zones)
-				}
+				t.fall.SetZonesFromArgs(c.RemainingArgs())
 
 			default:
 				return handler, c.ArgErr()
diff --git a/plugin/template/template.go b/plugin/template/template.go
index b11292dbd..a45ed0610 100644
--- a/plugin/template/template.go
+++ b/plugin/template/template.go
@@ -31,7 +31,7 @@ type template struct {
 	authority  []*gotmpl.Template
 	qclass     uint16
 	qtype      uint16
-	fthrough   fall.F
+	fall       fall.F
 }
 
 type templateData struct {
@@ -177,5 +177,5 @@ func (t template) match(state request.Request, zone string) (templateData, bool,
 		return data, true, false
 	}
 
-	return data, false, t.fthrough.Through(state.Name())
+	return data, false, t.fall.Through(state.Name())
 }
diff --git a/plugin/template/template_test.go b/plugin/template/template_test.go
index a815e8c7c..0a89be744 100644
--- a/plugin/template/template_test.go
+++ b/plugin/template/template_test.go
@@ -5,26 +5,25 @@ import (
 	"fmt"
 	"regexp"
 	"testing"
-
-	"github.com/coredns/coredns/plugin/test"
-	"github.com/mholt/caddy"
-
 	gotmpl "text/template"
 
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
 	"github.com/coredns/coredns/plugin/pkg/fall"
+	"github.com/coredns/coredns/plugin/test"
+
+	"github.com/mholt/caddy"
 	"github.com/miekg/dns"
 )
 
 func TestHandler(t *testing.T) {
 	rcodeFallthrough := 3841 // reserved for private use, used to indicate a fallthrough
 	exampleDomainATemplate := template{
-		regex:    []*regexp.Regexp{regexp.MustCompile("(^|[.])ip-10-(?P<b>[0-9]*)-(?P<c>[0-9]*)-(?P<d>[0-9]*)[.]example[.]$")},
-		answer:   []*gotmpl.Template{gotmpl.Must(gotmpl.New("answer").Parse("{{ .Name }} 60 IN A 10.{{ .Group.b }}.{{ .Group.c }}.{{ .Group.d }}"))},
-		qclass:   dns.ClassANY,
-		qtype:    dns.TypeANY,
-		fthrough: fall.F{Zones: []string{"."}},
-		zones:    []string{"."},
+		regex:  []*regexp.Regexp{regexp.MustCompile("(^|[.])ip-10-(?P<b>[0-9]*)-(?P<c>[0-9]*)-(?P<d>[0-9]*)[.]example[.]$")},
+		answer: []*gotmpl.Template{gotmpl.Must(gotmpl.New("answer").Parse("{{ .Name }} 60 IN A 10.{{ .Group.b }}.{{ .Group.c }}.{{ .Group.d }}"))},
+		qclass: dns.ClassANY,
+		qtype:  dns.TypeANY,
+		fall:   fall.F{Zones: []string{"."}},
+		zones:  []string{"."},
 	}
 	exampleDomainANSTemplate := template{
 		regex:      []*regexp.Regexp{regexp.MustCompile("(^|[.])ip-10-(?P<b>[0-9]*)-(?P<c>[0-9]*)-(?P<d>[0-9]*)[.]example[.]$")},
@@ -33,7 +32,7 @@ func TestHandler(t *testing.T) {
 		authority:  []*gotmpl.Template{gotmpl.Must(gotmpl.New("authority").Parse("example. IN NS ns0.example.com."))},
 		qclass:     dns.ClassANY,
 		qtype:      dns.TypeANY,
-		fthrough:   fall.F{Zones: []string{"."}},
+		fall:       fall.F{Zones: []string{"."}},
 		zones:      []string{"."},
 	}
 	exampleDomainMXTemplate := template{
@@ -42,48 +41,48 @@ func TestHandler(t *testing.T) {
 		additional: []*gotmpl.Template{gotmpl.Must(gotmpl.New("additional").Parse("{{ .Name }} 60 IN A 10.{{ .Group.b }}.{{ .Group.c }}.{{ .Group.d }}"))},
 		qclass:     dns.ClassANY,
 		qtype:      dns.TypeANY,
-		fthrough:   fall.F{Zones: []string{"."}},
+		fall:       fall.F{Zones: []string{"."}},
 		zones:      []string{"."},
 	}
 	invalidDomainTemplate := template{
-		regex:    []*regexp.Regexp{regexp.MustCompile("[.]invalid[.]$")},
-		rcode:    dns.RcodeNameError,
-		answer:   []*gotmpl.Template{gotmpl.Must(gotmpl.New("answer").Parse("invalid. 60 {{ .Class }} SOA a.invalid. b.invalid. (1 60 60 60 60)"))},
-		qclass:   dns.ClassANY,
-		qtype:    dns.TypeANY,
-		fthrough: fall.F{Zones: []string{"."}},
-		zones:    []string{"."},
+		regex:  []*regexp.Regexp{regexp.MustCompile("[.]invalid[.]$")},
+		rcode:  dns.RcodeNameError,
+		answer: []*gotmpl.Template{gotmpl.Must(gotmpl.New("answer").Parse("invalid. 60 {{ .Class }} SOA a.invalid. b.invalid. (1 60 60 60 60)"))},
+		qclass: dns.ClassANY,
+		qtype:  dns.TypeANY,
+		fall:   fall.F{Zones: []string{"."}},
+		zones:  []string{"."},
 	}
 	rcodeServfailTemplate := template{
-		regex:    []*regexp.Regexp{regexp.MustCompile(".*")},
-		rcode:    dns.RcodeServerFailure,
-		qclass:   dns.ClassANY,
-		qtype:    dns.TypeANY,
-		fthrough: fall.F{Zones: []string{"."}},
-		zones:    []string{"."},
+		regex:  []*regexp.Regexp{regexp.MustCompile(".*")},
+		rcode:  dns.RcodeServerFailure,
+		qclass: dns.ClassANY,
+		qtype:  dns.TypeANY,
+		fall:   fall.F{Zones: []string{"."}},
+		zones:  []string{"."},
 	}
 	brokenTemplate := template{
-		regex:    []*regexp.Regexp{regexp.MustCompile("[.]example[.]$")},
-		answer:   []*gotmpl.Template{gotmpl.Must(gotmpl.New("answer").Parse("{{ .Name }} 60 IN TXT \"{{ index .Match 2 }}\""))},
-		qclass:   dns.ClassANY,
-		qtype:    dns.TypeANY,
-		fthrough: fall.F{Zones: []string{"."}},
-		zones:    []string{"."},
+		regex:  []*regexp.Regexp{regexp.MustCompile("[.]example[.]$")},
+		answer: []*gotmpl.Template{gotmpl.Must(gotmpl.New("answer").Parse("{{ .Name }} 60 IN TXT \"{{ index .Match 2 }}\""))},
+		qclass: dns.ClassANY,
+		qtype:  dns.TypeANY,
+		fall:   fall.F{Zones: []string{"."}},
+		zones:  []string{"."},
 	}
 	nonRRTemplate := template{
-		regex:    []*regexp.Regexp{regexp.MustCompile("[.]example[.]$")},
-		answer:   []*gotmpl.Template{gotmpl.Must(gotmpl.New("answer").Parse("{{ .Name }}"))},
-		qclass:   dns.ClassANY,
-		qtype:    dns.TypeANY,
-		fthrough: fall.F{Zones: []string{"."}},
-		zones:    []string{"."},
+		regex:  []*regexp.Regexp{regexp.MustCompile("[.]example[.]$")},
+		answer: []*gotmpl.Template{gotmpl.Must(gotmpl.New("answer").Parse("{{ .Name }}"))},
+		qclass: dns.ClassANY,
+		qtype:  dns.TypeANY,
+		fall:   fall.F{Zones: []string{"."}},
+		zones:  []string{"."},
 	}
 	nonRRAdditionalTemplate := template{
 		regex:      []*regexp.Regexp{regexp.MustCompile("[.]example[.]$")},
 		additional: []*gotmpl.Template{gotmpl.Must(gotmpl.New("answer").Parse("{{ .Name }}"))},
 		qclass:     dns.ClassANY,
 		qtype:      dns.TypeANY,
-		fthrough:   fall.F{Zones: []string{"."}},
+		fall:       fall.F{Zones: []string{"."}},
 		zones:      []string{"."},
 	}
 	nonRRAuthoritativeTemplate := template{
@@ -91,7 +90,7 @@ func TestHandler(t *testing.T) {
 		authority: []*gotmpl.Template{gotmpl.Must(gotmpl.New("authority").Parse("{{ .Name }}"))},
 		qclass:    dns.ClassANY,
 		qtype:     dns.TypeANY,
-		fthrough:  fall.F{Zones: []string{"."}},
+		fall:      fall.F{Zones: []string{"."}},
 		zones:     []string{"."},
 	}