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/pprof/README.md

@@ -0,0 +1,41 @@
+# pprof
+
+*pprof* publishes runtime profiling data at endpoints under /debug/pprof.
+
+You can visit `/debug/pprof` on your site for an index of the available endpoints. By default it
+will listen on localhost:6053.
+
+> This is a debugging tool. Certain requests (such as collecting execution traces) can be slow. If
+> you use pprof on a live site, consider restricting access or enabling it only temporarily.
+
+For more information, please see [Go's pprof
+documentation](https://golang.org/pkg/net/http/pprof/) and read
+[Profiling Go Programs](https://blog.golang.org/profiling-go-programs).
+
+## Syntax
+
+~~~
+pprof [ADDRESS]
+~~~
+
+If not specified, ADDRESS defaults to localhost:6053.
+
+## Examples
+
+Enable pprof endpoints:
+
+~~~
+pprof
+~~~
+
+Listen on an alternate address:
+
+~~~
+pprof 10.9.8.7:6060
+~~~
+
+Listen on an all addresses on port 6060:
+
+~~~
+pprof :6060
+~~~

plugin/pprof/pprof.go

@@ -0,0 +1,49 @@
+// Package pprof implement a debug endpoint for getting profiles using the
+// go pprof tooling.
+package pprof
+
+import (
+	"log"
+	"net"
+	"net/http"
+	pp "net/http/pprof"
+)
+
+type handler struct {
+	addr string
+	ln   net.Listener
+	mux  *http.ServeMux
+}
+
+func (h *handler) Startup() error {
+	ln, err := net.Listen("tcp", h.addr)
+	if err != nil {
+		log.Printf("[ERROR] Failed to start pprof handler: %s", err)
+		return err
+	}
+
+	h.ln = ln
+
+	h.mux = http.NewServeMux()
+	h.mux.HandleFunc(path+"/", pp.Index)
+	h.mux.HandleFunc(path+"/cmdline", pp.Cmdline)
+	h.mux.HandleFunc(path+"/profile", pp.Profile)
+	h.mux.HandleFunc(path+"/symbol", pp.Symbol)
+	h.mux.HandleFunc(path+"/trace", pp.Trace)
+
+	go func() {
+		http.Serve(h.ln, h.mux)
+	}()
+	return nil
+}
+
+func (h *handler) Shutdown() error {
+	if h.ln != nil {
+		return h.ln.Close()
+	}
+	return nil
+}
+
+const (
+	path = "/debug/pprof"
+)

plugin/pprof/setup.go

@@ -0,0 +1,53 @@
+package pprof
+
+import (
+	"net"
+	"sync"
+
+	"github.com/coredns/coredns/plugin"
+
+	"github.com/mholt/caddy"
+)
+
+const defaultAddr = "localhost:6053"
+
+func init() {
+	caddy.RegisterPlugin("pprof", caddy.Plugin{
+		ServerType: "dns",
+		Action:     setup,
+	})
+}
+
+func setup(c *caddy.Controller) error {
+	found := false
+	h := &handler{addr: defaultAddr}
+	for c.Next() {
+		if found {
+			return plugin.Error("pprof", c.Err("pprof can only be specified once"))
+		}
+		args := c.RemainingArgs()
+		if len(args) == 1 {
+			h.addr = args[0]
+			_, _, e := net.SplitHostPort(h.addr)
+			if e != nil {
+				return e
+			}
+		}
+		if len(args) > 1 {
+			return plugin.Error("pprof", c.ArgErr())
+		}
+		if c.NextBlock() {
+			return plugin.Error("pprof", c.ArgErr())
+		}
+		found = true
+	}
+
+	pprofOnce.Do(func() {
+		c.OnStartup(h.Startup)
+		c.OnShutdown(h.Shutdown)
+	})
+
+	return nil
+}
+
+var pprofOnce sync.Once

plugin/pprof/setup_test.go

@@ -0,0 +1,34 @@
+package pprof
+
+import (
+	"testing"
+
+	"github.com/mholt/caddy"
+)
+
+func TestPProf(t *testing.T) {
+	tests := []struct {
+		input     string
+		shouldErr bool
+	}{
+		{`pprof`, false},
+		{`pprof 1.2.3.4:1234`, false},
+		{`pprof :1234`, false},
+		{`pprof {}`, true},
+		{`pprof /foo`, true},
+		{`pprof {
+            a b
+        }`, true},
+		{`pprof
+          pprof`, true},
+	}
+	for i, test := range tests {
+		c := caddy.NewTestController("dns", test.input)
+		err := setup(c)
+		if test.shouldErr && err == nil {
+			t.Errorf("Test %v: Expected error but found nil", i)
+		} else if !test.shouldErr && err != nil {
+			t.Errorf("Test %v: Expected no error but found error: %v", i, err)
+		}
+	}
+}