Upgrade to latest coredns standards

* add ready, remove health
* use plugin.Register

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

README.md

@@ -23,9 +23,9 @@ If monitoring is enabled (via the *prometheus* directive) the following metric i
 
 The `server` label indicated which server handled the request, see the *metrics* plugin for details.
 
-## Health
+## Ready
 
-This plugin implements dynamic health checking. It will always return healthy though.
+This plugin reports readiness to the ready plugin. It will be immediately ready.
 
 ## Examples
 

example.go

@@ -4,6 +4,7 @@
 package example
 
 import (
+	"context"
 	"fmt"
 	"io"
 	"os"
@@ -13,7 +14,6 @@ import (
 	clog "github.com/coredns/coredns/plugin/pkg/log"
 
 	"github.com/miekg/dns"
-	"golang.org/x/net/context"
 )
 
 // Define log to be a logger with the plugin name in it. This way we can just use log.Info and

example_test.go

@@ -2,13 +2,13 @@ package example
 
 import (
 	"bytes"
+	"context"
 	"testing"
 
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
 	"github.com/coredns/coredns/plugin/test"
 
 	"github.com/miekg/dns"
-	"golang.org/x/net/context"
 )
 
 func TestExample(t *testing.T) {

go.mod

@@ -1,10 +1,10 @@
 module github.com/coredns/example
 
-go 1.12
+go 1.13
 
 require (
 	github.com/caddyserver/caddy v1.0.1
-	github.com/coredns/coredns v1.5.2
+	github.com/coredns/coredns v1.6.3
 	github.com/miekg/dns v1.1.15
 	github.com/prometheus/client_golang v1.0.0
 	golang.org/x/net v0.0.0-20190628185345-da137c7871d7

health.go

@@ -1,14 +0,0 @@
-package example
-
-// Health implements the health.Healther interface.
-func (e Example) Health() bool {
-	// More advanced plugins will check their state, i.e. are they
-	// synchronized correctly against their backend etc.
-
-	// Be careful though by making this a single point of failure. I.e. if 5 CoreDNS
-	// instances are talking to the same backend and the backend goes down, *all* your
-	// instances are unhealthy.
-
-	// This one just returns OK.
-	return true
-}

ready.go

@@ -0,0 +1,5 @@
+package example
+
+// Ready implements the ready.Readiness interface, once this flips to true CoreDNS
+// assumes this plugin is ready for queries; it is not checked again.
+func (e Example) Ready() bool { return true }

setup.go

@@ -8,14 +8,8 @@ import (
 	"github.com/caddyserver/caddy"
 )
 
-// init registers this plugin within the Caddy plugin framework. It uses "example" as the
-// name, and couples it to the Action "setup".
-func init() {
-	caddy.RegisterPlugin("example", caddy.Plugin{
-		ServerType: "dns",
-		Action:     setup,
-	})
-}
+// init registers this plugin.
+func init() { plugin.Register("example", setup) }
 
 // setup is the function that gets called when the config parser see the token "example". Setup is responsible
 // for parsing any extra options the example plugin may have. The first token this function sees is "example".