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/erratic/README.md

@@ -0,0 +1,76 @@
+# erratic
+
+*erratic* is a plugin useful for testing client behavior. It returns a static response to all
+queries, but the responses can be delayed, dropped or truncated.
+
+The *erratic* plugin will respond to every A or AAAA query. For any other type it will return
+a SERVFAIL response. The reply for A will return 192.0.2.53 (see RFC 5737), for AAAA it returns
+2001:DB8::53 (see RFC 3849).
+
+*erratic* can also be used in conjunction with the *autopath* plugin. This is mostly to aid in
+ testing.
+
+## Syntax
+
+~~~ txt
+erratic {
+    drop [AMOUNT]
+    truncate [AMOUNT]
+    delay [AMOUNT [DURATION]]
+}
+~~~
+
+* `drop`: drop 1 per **AMOUNT** of queries, the default is 2.
+* `truncate`: truncate 1 per **AMOUNT** of queries, the default is 2.
+* `delay`: delay 1 per **AMOUNT** of queries for **DURATION**, the default for **AMOUNT** is 2 and
+  the default for **DURATION** is 100ms.
+
+## Examples
+
+~~~ txt
+.:53 {
+    erratic {
+        drop 3
+    }
+}
+~~~
+
+Or even shorter if the defaults suits you. Note this only drops queries, it does not delay them.
+
+~~~ txt
+. {
+    erratic
+}
+~~~
+
+Delay 1 in 3 queries for 50ms
+
+~~~ txt
+. {
+    erratic {
+        delay 3 50ms
+    }
+}
+~~~
+
+Delay 1 in 3 and truncate 1 in 5.
+
+~~~ txt
+. {
+    erratic {
+        delay 3 5ms
+        truncate 5
+    }
+}
+~~~
+
+Drop every second query.
+
+~~~ txt
+. {
+    erratic {
+        drop 2
+        truncate 2
+    }
+}
+~~~

plugin/erratic/autopath.go

@@ -0,0 +1,8 @@
+package erratic
+
+import "github.com/coredns/coredns/request"
+
+// AutoPath implements the AutoPathFunc call from the autopath plugin.
+func (e *Erratic) AutoPath(state request.Request) []string {
+	return []string{"a.example.org.", "b.example.org.", ""}
+}

plugin/erratic/erratic.go

@@ -0,0 +1,95 @@
+// Package erratic implements a plugin that returns erratic answers (delayed, dropped).
+package erratic
+
+import (
+	"sync/atomic"
+	"time"
+
+	"github.com/coredns/coredns/request"
+
+	"github.com/miekg/dns"
+	"golang.org/x/net/context"
+)
+
+// Erratic is a plugin that returns erratic repsonses to each client.
+type Erratic struct {
+	drop uint64
+
+	delay    uint64
+	duration time.Duration
+
+	truncate uint64
+
+	q uint64 // counter of queries
+}
+
+// ServeDNS implements the plugin.Handler interface.
+func (e *Erratic) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
+	state := request.Request{W: w, Req: r}
+	drop := false
+	delay := false
+	trunc := false
+
+	queryNr := atomic.LoadUint64(&e.q)
+	atomic.AddUint64(&e.q, 1)
+
+	if e.drop > 0 && queryNr%e.drop == 0 {
+		drop = true
+	}
+	if e.delay > 0 && queryNr%e.delay == 0 {
+		delay = true
+	}
+	if e.truncate > 0 && queryNr&e.truncate == 0 {
+		trunc = true
+	}
+
+	m := new(dns.Msg)
+	m.SetReply(r)
+	m.Compress = true
+	m.Authoritative = true
+	if trunc {
+		m.Truncated = true
+	}
+
+	// small dance to copy rrA or rrAAAA into a non-pointer var that allows us to overwrite the ownername
+	// in a non-racy way.
+	switch state.QType() {
+	case dns.TypeA:
+		rr := *(rrA.(*dns.A))
+		rr.Header().Name = state.QName()
+		m.Answer = append(m.Answer, &rr)
+	case dns.TypeAAAA:
+		rr := *(rrAAAA.(*dns.AAAA))
+		rr.Header().Name = state.QName()
+		m.Answer = append(m.Answer, &rr)
+	default:
+		if !drop {
+			if delay {
+				time.Sleep(e.duration)
+			}
+			// coredns will return error.
+			return dns.RcodeServerFailure, nil
+		}
+	}
+
+	if drop {
+		return 0, nil
+	}
+
+	if delay {
+		time.Sleep(e.duration)
+	}
+
+	state.SizeAndDo(m)
+	w.WriteMsg(m)
+
+	return 0, nil
+}
+
+// Name implements the Handler interface.
+func (e *Erratic) Name() string { return "erratic" }
+
+var (
+	rrA, _    = dns.NewRR(". IN 0 A 192.0.2.53")
+	rrAAAA, _ = dns.NewRR(". IN 0 AAAA 2001:DB8::53")
+)

plugin/erratic/erratic_test.go

@@ -0,0 +1,79 @@
+package erratic
+
+import (
+	"testing"
+
+	"github.com/coredns/coredns/plugin/pkg/dnsrecorder"
+	"github.com/coredns/coredns/plugin/test"
+
+	"github.com/miekg/dns"
+	"golang.org/x/net/context"
+)
+
+func TestErraticDrop(t *testing.T) {
+	e := &Erratic{drop: 2} // 50% drops
+
+	tests := []struct {
+		expectedCode int
+		expectedErr  error
+		drop         bool
+	}{
+		{expectedCode: dns.RcodeSuccess, expectedErr: nil, drop: true},
+		{expectedCode: dns.RcodeSuccess, expectedErr: nil, drop: false},
+	}
+
+	ctx := context.TODO()
+
+	for i, tc := range tests {
+		req := new(dns.Msg)
+		req.SetQuestion("example.org.", dns.TypeA)
+
+		rec := dnsrecorder.New(&test.ResponseWriter{})
+		code, err := e.ServeDNS(ctx, rec, req)
+
+		if err != tc.expectedErr {
+			t.Errorf("Test %d: Expected error %q, but got %q", i, tc.expectedErr, err)
+		}
+		if code != int(tc.expectedCode) {
+			t.Errorf("Test %d: Expected status code %d, but got %d", i, tc.expectedCode, code)
+		}
+
+		if tc.drop && rec.Msg != nil {
+			t.Errorf("Test %d: Expected dropped message, but got %q", i, rec.Msg.Question[0].Name)
+		}
+	}
+}
+
+func TestErraticTruncate(t *testing.T) {
+	e := &Erratic{truncate: 2} // 50% drops
+
+	tests := []struct {
+		expectedCode int
+		expectedErr  error
+		truncate     bool
+	}{
+		{expectedCode: dns.RcodeSuccess, expectedErr: nil, truncate: true},
+		{expectedCode: dns.RcodeSuccess, expectedErr: nil, truncate: false},
+	}
+
+	ctx := context.TODO()
+
+	for i, tc := range tests {
+		req := new(dns.Msg)
+		req.SetQuestion("example.org.", dns.TypeA)
+
+		rec := dnsrecorder.New(&test.ResponseWriter{})
+		code, err := e.ServeDNS(ctx, rec, req)
+
+		if err != tc.expectedErr {
+			t.Errorf("Test %d: Expected error %q, but got %q", i, tc.expectedErr, err)
+		}
+		if code != int(tc.expectedCode) {
+			t.Errorf("Test %d: Expected status code %d, but got %d", i, tc.expectedCode, code)
+		}
+
+		if tc.truncate && !rec.Msg.Truncated {
+			t.Errorf("Test %d: Expected truncated message, but got %q", i, rec.Msg.Question[0].Name)
+		}
+	}
+}

plugin/erratic/setup.go

@@ -0,0 +1,117 @@
+package erratic
+
+import (
+	"fmt"
+	"strconv"
+	"time"
+
+	"github.com/coredns/coredns/core/dnsserver"
+	"github.com/coredns/coredns/plugin"
+
+	"github.com/mholt/caddy"
+)
+
+func init() {
+	caddy.RegisterPlugin("erratic", caddy.Plugin{
+		ServerType: "dns",
+		Action:     setupErratic,
+	})
+}
+
+func setupErratic(c *caddy.Controller) error {
+	e, err := parseErratic(c)
+	if err != nil {
+		return plugin.Error("erratic", err)
+	}
+
+	dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
+		return e
+	})
+
+	return nil
+}
+
+func parseErratic(c *caddy.Controller) (*Erratic, error) {
+	e := &Erratic{drop: 2}
+	drop := false // true if we've seen the drop keyword
+
+	for c.Next() { // 'erratic'
+		for c.NextBlock() {
+			switch c.Val() {
+			case "drop":
+				args := c.RemainingArgs()
+				if len(args) > 1 {
+					return nil, c.ArgErr()
+				}
+
+				if len(args) == 0 {
+					continue
+				}
+
+				amount, err := strconv.ParseInt(args[0], 10, 32)
+				if err != nil {
+					return nil, err
+				}
+				if amount < 0 {
+					return nil, fmt.Errorf("illegal amount value given %q", args[0])
+				}
+				e.drop = uint64(amount)
+				drop = true
+			case "delay":
+				args := c.RemainingArgs()
+				if len(args) > 2 {
+					return nil, c.ArgErr()
+				}
+
+				// Defaults.
+				e.delay = 2
+				e.duration = 100 * time.Millisecond
+				if len(args) == 0 {
+					continue
+				}
+
+				amount, err := strconv.ParseInt(args[0], 10, 32)
+				if err != nil {
+					return nil, err
+				}
+				if amount < 0 {
+					return nil, fmt.Errorf("illegal amount value given %q", args[0])
+				}
+				e.delay = uint64(amount)
+
+				if len(args) > 1 {
+					duration, err := time.ParseDuration(args[1])
+					if err != nil {
+						return nil, err
+					}
+					e.duration = duration
+				}
+			case "truncate":
+				args := c.RemainingArgs()
+				if len(args) > 1 {
+					return nil, c.ArgErr()
+				}
+
+				if len(args) == 0 {
+					continue
+				}
+
+				amount, err := strconv.ParseInt(args[0], 10, 32)
+				if err != nil {
+					return nil, err
+				}
+				if amount < 0 {
+					return nil, fmt.Errorf("illegal amount value given %q", args[0])
+				}
+				e.truncate = uint64(amount)
+			default:
+				return nil, c.Errf("unknown property '%s'", c.Val())
+			}
+		}
+	}
+	if (e.delay > 0 || e.truncate > 0) && !drop { // delay is set, but we've haven't seen a drop keyword, remove default drop stuff
+		e.drop = 0
+	}
+
+	return e, nil
+}

plugin/erratic/setup_test.go

@@ -0,0 +1,103 @@
+package erratic
+
+import (
+	"testing"
+
+	"github.com/mholt/caddy"
+)
+
+func TestSetupErratic(t *testing.T) {
+	c := caddy.NewTestController("dns", `erratic {
+		drop
+	}`)
+	if err := setupErratic(c); err != nil {
+		t.Fatalf("Test 1, expected no errors, but got: %q", err)
+	}
+
+	c = caddy.NewTestController("dns", `erratic`)
+	if err := setupErratic(c); err != nil {
+		t.Fatalf("Test 2, expected no errors, but got: %q", err)
+	}
+
+	c = caddy.NewTestController("dns", `erratic {
+		drop -1
+	}`)
+	if err := setupErratic(c); err == nil {
+		t.Fatalf("Test 4, expected errors, but got: %q", err)
+	}
+}
+
+func TestParseErratic(t *testing.T) {
+	tests := []struct {
+		input     string
+		shouldErr bool
+		drop      uint64
+		delay     uint64
+		truncate  uint64
+	}{
+		// oks
+		{`erratic`, false, 2, 0, 0},
+		{`erratic {
+			drop 2
+			delay 3 1ms
+
+		}`, false, 2, 3, 0},
+		{`erratic {
+			truncate 2
+			delay 3 1ms
+
+		}`, false, 0, 3, 2},
+		{`erraric {
+			drop 3
+			delay
+		}`, false, 3, 2, 0},
+		// fails
+		{`erratic {
+			drop -1
+		}`, true, 0, 0, 0},
+		{`erratic {
+			delay -1
+		}`, true, 0, 0, 0},
+		{`erratic {
+			delay 1 2 4
+		}`, true, 0, 0, 0},
+		{`erratic {
+			delay 15.a
+		}`, true, 0, 0, 0},
+		{`erraric {
+			drop 3
+			delay 3 bla
+		}`, true, 0, 0, 0},
+		{`erraric {
+			truncate 15.a
+		}`, true, 0, 0, 0},
+		{`erraric {
+			something-else
+		}`, true, 0, 0, 0},
+	}
+	for i, test := range tests {
+		c := caddy.NewTestController("dns", test.input)
+		e, err := parseErratic(c)
+		if test.shouldErr && err == nil {
+			t.Errorf("Test %v: Expected error but found nil", i)
+			continue
+		} else if !test.shouldErr && err != nil {
+			t.Errorf("Test %v: Expected no error but found error: %v", i, err)
+			continue
+		}
+
+		if test.shouldErr {
+			continue
+		}
+
+		if test.delay != e.delay {
+			t.Errorf("Test %v: Expected delay %d but found: %d", i, test.delay, e.delay)
+		}
+		if test.drop != e.drop {
+			t.Errorf("Test %v: Expected drop %d but found: %d", i, test.drop, e.drop)
+		}
+		if test.truncate != e.truncate {
+			t.Errorf("Test %v: Expected truncate %d but found: %d", i, test.truncate, e.truncate)
+		}
+	}
+}