Startup notification (#250)

Stop the caddy message and start our own init notifications.
Log the version of CoreDNS when starting up.
Fix all middleware's setup functions so that return the error prefixed
with *which* middleware was failing; leads to better debuggable errors
when starting up.

middleware/bind/setup.go

@@ -5,6 +5,7 @@ import (
 	"net"
 
 	"github.com/miekg/coredns/core/dnsserver"
+	"github.com/miekg/coredns/middleware"
 
 	"github.com/mholt/caddy"
 )
@@ -13,11 +14,11 @@ func setupBind(c *caddy.Controller) error {
 	config := dnsserver.GetConfig(c)
 	for c.Next() {
 		if !c.Args(&config.ListenHost) {
-			return c.ArgErr()
+			return middleware.Error("bind", c.ArgErr())
 		}
 	}
 	if net.ParseIP(config.ListenHost) == nil {
-		return fmt.Errorf("not a valid IP address: %s", config.ListenHost)
+		return middleware.Error("bind", fmt.Errorf("not a valid IP address: %s", config.ListenHost))
 	}
 	return nil
 }

middleware/cache/setup.go

@@ -20,7 +20,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	ttl, zones, err := cacheParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("cache", err)
 	}
 	dnsserver.GetConfig(c).AddMiddleware(func(next dnsserver.Handler) dnsserver.Handler {
 		return NewCache(ttl, zones, next)

middleware/chaos/setup.go

@@ -2,6 +2,7 @@ package chaos
 
 import (
 	"github.com/miekg/coredns/core/dnsserver"
+	"github.com/miekg/coredns/middleware"
 
 	"github.com/mholt/caddy"
 )
@@ -16,7 +17,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	version, authors, err := chaosParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("chaos", err)
 	}
 
 	dnsserver.GetConfig(c).AddMiddleware(func(next dnsserver.Handler) dnsserver.Handler {

middleware/dnssec/setup.go

@@ -19,7 +19,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	zones, keys, err := dnssecParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("dnssec", err)
 	}
 
 	dnsserver.GetConfig(c).AddMiddleware(func(next dnsserver.Handler) dnsserver.Handler {

middleware/errors/setup.go

@@ -6,6 +6,7 @@ import (
 	"os"
 
 	"github.com/miekg/coredns/core/dnsserver"
+	"github.com/miekg/coredns/middleware"
 	"github.com/miekg/coredns/middleware/pkg/roller"
 
 	"github.com/hashicorp/go-syslog"
@@ -22,7 +23,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	handler, err := errorsParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("errors", err)
 	}
 
 	var writer io.Writer
@@ -37,7 +38,7 @@ func setup(c *caddy.Controller) error {
 	case "syslog":
 		writer, err = gsyslog.NewLogger(gsyslog.LOG_ERR, "LOCAL0", "coredns")
 		if err != nil {
-			return err
+			return middleware.Error("errors", err)
 		}
 	default:
 		if handler.LogFile == "" {
@@ -48,7 +49,7 @@ func setup(c *caddy.Controller) error {
 		var file *os.File
 		file, err = os.OpenFile(handler.LogFile, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
 		if err != nil {
-			return err
+			return middleware.Error("errors", err)
 		}
 		if handler.LogRoller != nil {
 			file.Close()

middleware/etcd/setup.go

@@ -28,7 +28,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	e, stubzones, err := etcdParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("etcd", err)
 	}
 	if stubzones {
 		c.OnStartup(func() error {

middleware/file/setup.go

@@ -21,7 +21,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	zones, err := fileParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("file", err)
 	}
 
 	// Add startup functions to notify the master(s).

middleware/health/setup.go

@@ -1,6 +1,10 @@
 package health
 
-import "github.com/mholt/caddy"
+import (
+	"github.com/miekg/coredns/middleware"
+
+	"github.com/mholt/caddy"
+)
 
 func init() {
 	caddy.RegisterPlugin("health", caddy.Plugin{
@@ -12,7 +16,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	addr, err := healthParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("health", err)
 	}
 
 	health := &Health{Addr: addr}

middleware/kubernetes/setup.go

@@ -24,12 +24,12 @@ func init() {
 func setup(c *caddy.Controller) error {
 	kubernetes, err := kubernetesParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("kubernetes", err)
 	}
 
 	err = kubernetes.InitKubeCache()
 	if err != nil {
-		return err
+		return middleware.Error("kubernetes", err)
 	}
 
 	// Register KubeCache start and stop functions with Caddy

middleware/log/setup.go

@@ -6,6 +6,7 @@ import (
 	"os"
 
 	"github.com/miekg/coredns/core/dnsserver"
+	"github.com/miekg/coredns/middleware"
 	"github.com/miekg/coredns/middleware/pkg/roller"
 
 	"github.com/hashicorp/go-syslog"
@@ -23,7 +24,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	rules, err := logParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("log", err)
 	}
 
 	// Open the log files for writing when the server starts
@@ -39,13 +40,13 @@ func setup(c *caddy.Controller) error {
 			} else if rules[i].OutputFile == "syslog" {
 				writer, err = gsyslog.NewLogger(gsyslog.LOG_INFO, "LOCAL0", "coredns")
 				if err != nil {
-					return err
+					return middleware.Error("log", err)
 				}
 			} else {
 				var file *os.File
 				file, err = os.OpenFile(rules[i].OutputFile, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
 				if err != nil {
-					return err
+					return middleware.Error("log", err)
 				}
 				if rules[i].Roller != nil {
 					file.Close()

middleware/metrics/setup.go

@@ -19,7 +19,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	m, err := prometheusParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("prometheus", err)
 	}
 
 	dnsserver.GetConfig(c).AddMiddleware(func(next dnsserver.Handler) dnsserver.Handler {

middleware/middleware.go

@@ -2,6 +2,8 @@
 package middleware
 
 import (
+	"fmt"
+
 	"github.com/miekg/dns"
 	"golang.org/x/net/context"
 )
@@ -52,4 +54,8 @@ func (f HandlerFunc) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.
 	return f(ctx, w, r)
 }
 
+// Error returns err with 'middleware/name: ' prefixed to it.
+func Error(name string, err error) error { return fmt.Errorf("%s/%s: %s", "middleware", name, err) }
+
+// Namespace is the namespace used for the metrics.
 const Namespace = "coredns"

middleware/pprof/setup.go

@@ -4,6 +4,7 @@ import (
 	"sync"
 
 	"github.com/mholt/caddy"
+	"github.com/miekg/coredns/middleware"
 )
 
 func init() {
@@ -17,13 +18,13 @@ func setup(c *caddy.Controller) error {
 	found := false
 	for c.Next() {
 		if found {
-			return c.Err("pprof can only be specified once")
+			return middleware.Error("pprof", c.Err("pprof can only be specified once"))
 		}
 		if len(c.RemainingArgs()) != 0 {
-			return c.ArgErr()
+			return middleware.Error("pprof", c.ArgErr())
 		}
 		if c.NextBlock() {
-			return c.ArgErr()
+			return middleware.Error("pprof", c.ArgErr())
 		}
 		found = true
 	}

middleware/proxy/setup.go

@@ -2,6 +2,7 @@ package proxy
 
 import (
 	"github.com/miekg/coredns/core/dnsserver"
+	"github.com/miekg/coredns/middleware"
 
 	"github.com/mholt/caddy"
 )
@@ -16,7 +17,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	upstreams, err := NewStaticUpstreams(c.Dispenser)
 	if err != nil {
-		return err
+		return middleware.Error("proxy", err)
 	}
 	dnsserver.GetConfig(c).AddMiddleware(func(next dnsserver.Handler) dnsserver.Handler {
 		return Proxy{Next: next, Client: Clients(), Upstreams: upstreams}

middleware/rewrite/setup.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"github.com/miekg/coredns/core/dnsserver"
+	"github.com/miekg/coredns/middleware"
 
 	"github.com/mholt/caddy"
 )
@@ -19,7 +20,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	rewrites, err := rewriteParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("rewrite", err)
 	}
 
 	dnsserver.GetConfig(c).AddMiddleware(func(next dnsserver.Handler) dnsserver.Handler {

middleware/secondary/setup.go

@@ -18,7 +18,7 @@ func init() {
 func setup(c *caddy.Controller) error {
 	zones, err := secondaryParse(c)
 	if err != nil {
-		return err
+		return middleware.Error("secondary", err)
 	}
 
 	// Add startup functions to retrieve the zone and keep it up to date.