Remove the word middleware (#1067)

* Rename middleware to plugin

first pass; mostly used 'sed', few spots where I manually changed
text.

This still builds a coredns binary.

* fmt error

* Rename AddMiddleware to AddPlugin

* Readd AddMiddleware to remain backwards compat

plugin/log/setup.go

@@ -0,0 +1,116 @@
+package log
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/coredns/coredns/core/dnsserver"
+	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/plugin/pkg/response"
+
+	"github.com/mholt/caddy"
+	"github.com/miekg/dns"
+)
+
+func init() {
+	caddy.RegisterPlugin("log", caddy.Plugin{
+		ServerType: "dns",
+		Action:     setup,
+	})
+}
+
+func setup(c *caddy.Controller) error {
+	rules, err := logParse(c)
+	if err != nil {
+		return plugin.Error("log", err)
+	}
+
+	// Open the log files for writing when the server starts
+	c.OnStartup(func() error {
+		for i := 0; i < len(rules); i++ {
+			// We only support stdout
+			writer := os.Stdout
+			if rules[i].OutputFile != "stdout" {
+				return plugin.Error("log", fmt.Errorf("invalid log file: %s", rules[i].OutputFile))
+			}
+
+			rules[i].Log = log.New(writer, "", 0)
+		}
+
+		return nil
+	})
+
+	dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
+		return Logger{Next: next, Rules: rules, ErrorFunc: dnsserver.DefaultErrorFunc}
+	})
+
+	return nil
+}
+
+func logParse(c *caddy.Controller) ([]Rule, error) {
+	var rules []Rule
+
+	for c.Next() {
+		args := c.RemainingArgs()
+
+		if len(args) == 0 {
+			// Nothing specified; use defaults
+			rules = append(rules, Rule{
+				NameScope:  ".",
+				OutputFile: DefaultLogFilename,
+				Format:     DefaultLogFormat,
+			})
+		} else if len(args) == 1 {
+			// Only an output file specified.
+			rules = append(rules, Rule{
+				NameScope:  ".",
+				OutputFile: args[0],
+				Format:     DefaultLogFormat,
+			})
+		} else {
+			// Name scope, output file, and maybe a format specified
+
+			format := DefaultLogFormat
+
+			if len(args) > 2 {
+				switch args[2] {
+				case "{common}":
+					format = CommonLogFormat
+				case "{combined}":
+					format = CombinedLogFormat
+				default:
+					format = args[2]
+				}
+			}
+
+			rules = append(rules, Rule{
+				NameScope:  dns.Fqdn(args[0]),
+				OutputFile: args[1],
+				Format:     format,
+			})
+		}
+
+		// Class refinements in an extra block.
+		for c.NextBlock() {
+			switch c.Val() {
+			// class followed by all, denial, error or success.
+			case "class":
+				classes := c.RemainingArgs()
+				if len(classes) == 0 {
+					return nil, c.ArgErr()
+				}
+				cls, err := response.ClassFromString(classes[0])
+				if err != nil {
+					return nil, err
+				}
+				// update class and the last added Rule (bit icky)
+				rules[len(rules)-1].Class = cls
+			default:
+				return nil, c.ArgErr()
+			}
+		}
+	}
+
+	return rules, nil
+}