plugin/chaos: add default list of authors (#2737)

* plugin/chaos: add default list of authors

Add a owners_generate.go that generates a Owners variables for use in
the chaos plugin.

Add a default list of authors in the authors.bind CH zone. When doing a
query this now returns:

~~~ sh
% dig authors.bind TXT CH

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5456
;; flags: qr rd; QUERY: 1, ANSWER: 22, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;authors.bind.			CH	TXT

;; ANSWER SECTION:
authors.bind.		0	CH	TXT	"bradbeam"
authors.bind.		0	CH	TXT	"chrisohaver"
authors.bind.		0	CH	TXT	"dilyevsky"
authors.bind.		0	CH	TXT	"ekleiner"
authors.bind.		0	CH	TXT	"fastest963"
authors.bind.		0	CH	TXT	"fturib"
authors.bind.		0	CH	TXT	"greenpau"
authors.bind.		0	CH	TXT	"grobie"
authors.bind.		0	CH	TXT	"inigohu"
authors.bind.		0	CH	TXT	"isolus"
authors.bind.		0	CH	TXT	"johnbelamaric"
authors.bind.		0	CH	TXT	"miekg"
authors.bind.		0	CH	TXT	"nchrisdk"
authors.bind.		0	CH	TXT	"nitisht"
authors.bind.		0	CH	TXT	"pmoroney"
authors.bind.		0	CH	TXT	"rajansandeep"
authors.bind.		0	CH	TXT	"rdrozhdzh"
authors.bind.		0	CH	TXT	"rtreffer"
authors.bind.		0	CH	TXT	"stp-ip"
authors.bind.		0	CH	TXT	"superq"
authors.bind.		0	CH	TXT	"varyoo"
authors.bind.		0	CH	TXT	"yongtang"
~~~

This was hard to do previously as we didn't hardcode this in the source,
but now with OWNERS files we can just generate this list.

Privacy wise this isn't worse than being listed in OWNERS file in the
first place. And it's a nice hat tip to the people making CoreDNS
better.

Signed-off-by: Miek Gieben <miek@miek.nl>

* Sticklet bot comments

Signed-off-by: Miek Gieben <miek@miek.nl>

9 files changed, 136 insertions, 28 deletions

diff --git a/coredns.go b/coredns.go
index 5b3fa2b8f..21bbdd02b 100644
--- a/coredns.go
+++ b/coredns.go
@@ -1,6 +1,7 @@
 package main
 
 //go:generate go run directives_generate.go
+//go:generate go run owners_generate.go
 
 import (
 	"github.com/coredns/coredns/coremain"
diff --git a/go.mod b/go.mod
index d09ac4449..0575191db 100644
--- a/go.mod
+++ b/go.mod
@@ -74,6 +74,7 @@ require (
 	gopkg.in/DataDog/dd-trace-go.v0 v0.6.1
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/ini.v1 v1.42.0 // indirect
+	gopkg.in/yaml.v2 v2.2.2
 	k8s.io/api v0.0.0-20181204000039-89a74a8d264d
 	k8s.io/apimachinery v0.0.0-20181127025237-2b1284ed4c93
 	k8s.io/client-go v10.0.0+incompatible
diff --git a/owners_generate.go b/owners_generate.go
new file mode 100644
index 000000000..e198f435f
--- /dev/null
+++ b/owners_generate.go
@@ -0,0 +1,91 @@
+//+build ignore
+
+// generates plugin/chaos/zowners.go.
+
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"path"
+	"path/filepath"
+	"sort"
+
+	"gopkg.in/yaml.v2"
+)
+
+func main() {
+	o := map[string]struct{}{}
+
+	// top-level OWNERS file
+	o, err := owners("OWNERS", o)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// each of the plugins, in case someone is not in the top-level one
+	err = filepath.Walk("plugin",
+		func(p string, i os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+			if i.IsDir() {
+				return nil
+			}
+			if path.Base(p) != "OWNERS" {
+				return nil
+			}
+			o, err = owners(p, o)
+			return err
+		})
+
+	// sort it and format it
+	list := []string{}
+	for k := range o {
+		list = append(list, k)
+	}
+	sort.Strings(list)
+	golist := `package chaos
+
+// Owners are all GitHub handlers of all maintainers.
+var Owners = []string{`
+	c := ", "
+	for i, a := range list {
+		if i == len(list)-1 {
+			c = "}"
+		}
+		golist += fmt.Sprintf("%q%s", a, c)
+	}
+
+	if err := ioutil.WriteFile("plugin/chaos/zowners.go", []byte(golist), 0644); err != nil {
+		log.Fatal(err)
+	}
+	return
+}
+
+// owners parses a owner file without knowning a whole lot about its structure.
+func owners(path string, owners map[string]struct{}) (map[string]struct{}, error) {
+	file, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	c := yaml.MapSlice{}
+	err = yaml.Unmarshal(file, &c)
+	if err != nil {
+		return nil, err
+	}
+	for _, mi := range c {
+		key, ok := mi.Key.(string)
+		if !ok {
+			continue
+		}
+		if key == "approvers" {
+			for _, k := range mi.Value.([]interface{}) {
+				owners[k.(string)] = struct{}{}
+			}
+		}
+	}
+	return owners, nil
+}
diff --git a/plugin/chaos/README.md b/plugin/chaos/README.md
index 8ddb2b0c7..3cd6dff41 100644
--- a/plugin/chaos/README.md
+++ b/plugin/chaos/README.md
@@ -16,7 +16,7 @@ chaos [VERSION] [AUTHORS...]
 ~~~
 
 * **VERSION** is the version to return. Defaults to `CoreDNS-<version>`, if not set.
-* **AUTHORS** is what authors to return. No default.
+* **AUTHORS** is what authors to return. This defaults to all GitHub handles in the OWNERS files.
 
 Note that you have to make sure that this plugin will get actual queries for the
 following zones: `version.bind`, `version.server`, `authors.bind`, `hostname.bind` and
diff --git a/plugin/chaos/chaos.go b/plugin/chaos/chaos.go
index af76a0bcf..42b1fb3f0 100644
--- a/plugin/chaos/chaos.go
+++ b/plugin/chaos/chaos.go
@@ -16,7 +16,7 @@ import (
 type Chaos struct {
 	Next    plugin.Handler
 	Version string
-	Authors map[string]struct{}
+	Authors []string
 }
 
 // ServeDNS implements the plugin.Handler interface.
@@ -32,13 +32,13 @@ func (c Chaos) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
 	hdr := dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeTXT, Class: dns.ClassCHAOS, Ttl: 0}
 	switch state.Name() {
 	default:
-		return c.Next.ServeDNS(ctx, w, r)
+		return plugin.NextOrFailure(c.Name(), c.Next, ctx, w, r)
 	case "authors.bind.":
-		for a := range c.Authors {
-			m.Answer = append(m.Answer, &dns.TXT{Hdr: hdr, Txt: []string{trim(a)}})
+		for _, a := range c.Authors {
+			m.Answer = append(m.Answer, &dns.TXT{Hdr: hdr, Txt: []string{a}})
 		}
 	case "version.bind.", "version.server.":
-		m.Answer = []dns.RR{&dns.TXT{Hdr: hdr, Txt: []string{trim(c.Version)}}}
+		m.Answer = []dns.RR{&dns.TXT{Hdr: hdr, Txt: []string{c.Version}}}
 	case "hostname.bind.", "id.server.":
 		hostname, err := os.Hostname()
 		if err != nil {
@@ -52,10 +52,3 @@ func (c Chaos) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
 
 // Name implements the Handler interface.
 func (c Chaos) Name() string { return "chaos" }
-
-func trim(s string) string {
-	if len(s) < 256 {
-		return s
-	}
-	return s[:255]
-}
diff --git a/plugin/chaos/chaos_test.go b/plugin/chaos/chaos_test.go
index 179aab90c..12cc1697e 100644
--- a/plugin/chaos/chaos_test.go
+++ b/plugin/chaos/chaos_test.go
@@ -14,7 +14,7 @@ import (
 func TestChaos(t *testing.T) {
 	em := Chaos{
 		Version: version,
-		Authors: map[string]struct{}{"Miek Gieben": struct{}{}},
+		Authors: []string{"Miek Gieben"},
 	}
 
 	tests := []struct {
diff --git a/plugin/chaos/setup.go b/plugin/chaos/setup.go
index 8028876cf..6cf5e09da 100644
--- a/plugin/chaos/setup.go
+++ b/plugin/chaos/setup.go
@@ -1,6 +1,10 @@
+//go:generate go run owners_generate.go
+
 package chaos
 
 import (
+	"sort"
+
 	"github.com/coredns/coredns/core/dnsserver"
 	"github.com/coredns/coredns/plugin"
 
@@ -16,7 +20,7 @@ func init() {
 }
 
 func setup(c *caddy.Controller) error {
-	version, authors, err := chaosParse(c)
+	version, authors, err := parse(c)
 	if err != nil {
 		return plugin.Error("chaos", err)
 	}
@@ -28,28 +32,42 @@ func setup(c *caddy.Controller) error {
 	return nil
 }
 
-func chaosParse(c *caddy.Controller) (string, map[string]struct{}, error) {
+func parse(c *caddy.Controller) (string, []string, error) {
 	// Set here so we pick up AppName and AppVersion that get set in coremain's init().
 	chaosVersion = caddy.AppName + "-" + caddy.AppVersion
-
 	version := ""
-	authors := make(map[string]struct{})
 
 	for c.Next() {
 		args := c.RemainingArgs()
 		if len(args) == 0 {
-			return chaosVersion, nil, nil
+			return trim(chaosVersion), Owners, nil
 		}
 		if len(args) == 1 {
-			return args[0], nil, nil
+			return trim(args[0]), Owners, nil
 		}
+
 		version = args[0]
+		authors := make(map[string]struct{})
 		for _, a := range args[1:] {
 			authors[a] = struct{}{}
 		}
-		return version, authors, nil
+		list := []string{}
+		for k := range authors {
+			k = trim(k) // limit size to 255 chars
+			list = append(list, k)
+		}
+		sort.Strings(list)
+		return version, list, nil
+	}
+
+	return version, Owners, nil
+}
+
+func trim(s string) string {
+	if len(s) < 256 {
+		return s
 	}
-	return version, authors, nil
+	return s[:255]
 }
 
 var chaosVersion string
diff --git a/plugin/chaos/setup_test.go b/plugin/chaos/setup_test.go
index 6f3c13fb3..b5cab4d29 100644
--- a/plugin/chaos/setup_test.go
+++ b/plugin/chaos/setup_test.go
@@ -12,7 +12,7 @@ func TestSetupChaos(t *testing.T) {
 		input              string
 		shouldErr          bool
 		expectedVersion    string // expected version.
-		expectedAuthor     string // expected author (string, although we get a map).
+		expectedAuthor     string // expected author (string, although we get a slice).
 		expectedErrContent string // substring from the expected error. Empty for positive cases.
 	}{
 		// positive
@@ -26,7 +26,7 @@ func TestSetupChaos(t *testing.T) {
 
 	for i, test := range tests {
 		c := caddy.NewTestController("dns", test.input)
-		version, authors, err := chaosParse(c)
+		version, authors, err := parse(c)
 
 		if test.shouldErr && err == nil {
 			t.Errorf("Test %d: Expected error but found %s for input %s", i, err, test.input)
@@ -43,11 +43,11 @@ func TestSetupChaos(t *testing.T) {
 		}
 
 		if !test.shouldErr && version != test.expectedVersion {
-			t.Errorf("Chaos not correctly set for input %s. Expected: %s, actual: %s", test.input, test.expectedVersion, version)
+			t.Errorf("Test %d: Chaos not correctly set for input %s. Expected: %s, actual: %s", i, test.input, test.expectedVersion, version)
 		}
-		if !test.shouldErr && authors != nil {
-			if _, ok := authors[test.expectedAuthor]; !ok {
-				t.Errorf("Chaos not correctly set for input %s. Expected: '%s', actual: '%s'", test.input, test.expectedAuthor, "Miek Gieben")
+		if !test.shouldErr && authors != nil && test.expectedAuthor != "" {
+			if authors[0] != test.expectedAuthor {
+				t.Errorf("Test %d: Chaos not correctly set for input %s. Expected: '%s', actual: '%s'", i, test.input, test.expectedAuthor, authors[0])
 			}
 		}
 	}
diff --git a/plugin/chaos/zowners.go b/plugin/chaos/zowners.go
new file mode 100644
index 000000000..c3668600e
--- /dev/null
+++ b/plugin/chaos/zowners.go
@@ -0,0 +1,4 @@
+package chaos
+
+// Owners are all GitHub handlers of all maintainers.
+var Owners = []string{"bradbeam", "chrisohaver", "dilyevsky", "ekleiner", "fastest963", "fturib", "greenpau", "grobie", "inigohu", "isolus", "johnbelamaric", "miekg", "nchrisdk", "nitisht", "pmoroney", "rajansandeep", "rdrozhdzh", "rtreffer", "stp-ip", "superq", "varyoo", "yongtang"}
\ No newline at end of file