middleware/{log,errors}: output everything to stdout (#684)

Limit the options in both errors and log middleware, just output to
stdout and let someone else (journald,docker) care about where to route
the logs. This removes syslog and logging to a file.

Fixes #573 #602

middleware/errors/setup.go

@@ -1,14 +1,13 @@
 package errors
 
 import (
-	"io"
+	"fmt"
 	"log"
 	"os"
 
 	"github.com/coredns/coredns/core/dnsserver"
 	"github.com/coredns/coredns/middleware"
 
-	"github.com/hashicorp/go-syslog"
 	"github.com/mholt/caddy"
 )
 
@@ -25,34 +24,7 @@ func setup(c *caddy.Controller) error {
 		return middleware.Error("errors", err)
 	}
 
-	var writer io.Writer
-
-	switch handler.LogFile {
-	case "visible":
-		handler.Debug = true
-	case "stdout":
-		writer = os.Stdout
-	case "stderr":
-		writer = os.Stderr
-	case "syslog":
-		writer, err = gsyslog.NewLogger(gsyslog.LOG_ERR, "LOCAL0", "coredns")
-		if err != nil {
-			return middleware.Error("errors", err)
-		}
-	default:
-		if handler.LogFile == "" {
-			writer = os.Stderr // default
-			break
-		}
-
-		var file *os.File
-		file, err = os.OpenFile(handler.LogFile, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
-		if err != nil {
-			return middleware.Error("errors", err)
-		}
-		writer = file
-	}
-	handler.Log = log.New(writer, "", 0)
+	handler.Log = log.New(os.Stdout, "", 0)
 
 	dnsserver.GetConfig(c).AddMiddleware(func(next middleware.Handler) middleware.Handler {
 		handler.Next = next
@@ -65,47 +37,19 @@ func setup(c *caddy.Controller) error {
 func errorsParse(c *caddy.Controller) (errorHandler, error) {
 	handler := errorHandler{}
 
-	optionalBlock := func() (bool, error) {
-		var hadBlock bool
-
-		for c.NextBlock() {
-			hadBlock = true
-
-			what := c.Val()
-			if !c.NextArg() {
-				return hadBlock, c.ArgErr()
-			}
-			where := c.Val()
-
-			if what == "log" {
-				if where == "visible" {
-					handler.Debug = true
-				} else {
-					handler.LogFile = where
-				}
-			}
-		}
-		return hadBlock, nil
-	}
-
 	for c.Next() {
-		// Configuration may be in a block
-		hadBlock, err := optionalBlock()
-		if err != nil {
-			return handler, err
-		}
-
-		// Otherwise, the only argument would be an error log file name or 'visible'
-		if !hadBlock {
-			if c.NextArg() {
-				if c.Val() == "visible" {
-					handler.Debug = true
-				} else {
-					handler.LogFile = c.Val()
-				}
+		args := c.RemainingArgs()
+		switch len(args) {
+		case 0:
+			handler.LogFile = "stdout"
+		case 1:
+			if args[0] != "stdout" {
+				return handler, fmt.Errorf("invalid log file: %s", args[0])
 			}
+			handler.LogFile = args[0]
+		default:
+			return handler, c.ArgErr()
 		}
 	}
-
 	return handler, nil
 }