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

6 files changed, 0 insertions, 289 deletions

diff --git a/middleware/health/README.md b/middleware/health/README.md
deleted file mode 100644
index 195a480c0..000000000
--- a/middleware/health/README.md
+++ /dev/null
@@ -1,23 +0,0 @@
-# health
-
-This module enables a simple health check endpoint. By default it will listen on port 8080.
-
-## Syntax
-
-~~~
-health [ADDRESS]
-~~~
-
-Optionally takes an address; the default is `:8080`. The health path is fixed to `/health`. The
-health endpoint returns a 200 response code and the word "OK" when CoreDNS is healthy. It returns
-a 503. *health* periodically (1s) polls middleware that exports health information. If any of the
-middleware signals that it is unhealthy, the server will go unhealthy too. Each middleware that
-supports health checks has a section "Health" in their README.
-
-## Examples
-
-Run another health endpoint on http://localhost:8091.
-
-~~~
-health localhost:8091
-~~~
diff --git a/middleware/health/health.go b/middleware/health/health.go
deleted file mode 100644
index 5e5c4c32f..000000000
--- a/middleware/health/health.go
+++ /dev/null
@@ -1,69 +0,0 @@
-// Package health implements an HTTP handler that responds to health checks.
-package health
-
-import (
-	"io"
-	"log"
-	"net"
-	"net/http"
-	"sync"
-)
-
-var once sync.Once
-
-type health struct {
-	Addr string
-
-	ln  net.Listener
-	mux *http.ServeMux
-
-	// A slice of Healthers that the health middleware will poll every second for their health status.
-	h []Healther
-	sync.RWMutex
-	ok bool // ok is the global boolean indicating an all healthy middleware stack
-}
-
-func (h *health) Startup() error {
-	if h.Addr == "" {
-		h.Addr = defAddr
-	}
-
-	once.Do(func() {
-		ln, err := net.Listen("tcp", h.Addr)
-		if err != nil {
-			log.Printf("[ERROR] Failed to start health handler: %s", err)
-			return
-		}
-
-		h.ln = ln
-
-		h.mux = http.NewServeMux()
-
-		h.mux.HandleFunc(path, func(w http.ResponseWriter, r *http.Request) {
-			if h.Ok() {
-				w.WriteHeader(http.StatusOK)
-				io.WriteString(w, ok)
-				return
-			}
-			w.WriteHeader(http.StatusServiceUnavailable)
-		})
-
-		go func() {
-			http.Serve(h.ln, h.mux)
-		}()
-	})
-	return nil
-}
-
-func (h *health) Shutdown() error {
-	if h.ln != nil {
-		return h.ln.Close()
-	}
-	return nil
-}
-
-const (
-	ok      = "OK"
-	defAddr = ":8080"
-	path    = "/health"
-)
diff --git a/middleware/health/health_test.go b/middleware/health/health_test.go
deleted file mode 100644
index ea22ad8b6..000000000
--- a/middleware/health/health_test.go
+++ /dev/null
@@ -1,47 +0,0 @@
-package health
-
-// TODO(miek): enable again if middleware gets health check.
-/*
-func TestHealth(t *testing.T) {
-	h := health{Addr: ":0"}
-	h.h = append(h.h, &erratic.Erratic{})
-
-	if err := h.Startup(); err != nil {
-		t.Fatalf("Unable to startup the health server: %v", err)
-	}
-	defer h.Shutdown()
-
-	// Reconstruct the http address based on the port allocated by operating system.
-	address := fmt.Sprintf("http://%s%s", h.ln.Addr().String(), path)
-
-	// Norhing set should be unhealthy
-	response, err := http.Get(address)
-	if err != nil {
-		t.Fatalf("Unable to query %s: %v", address, err)
-	}
-	if response.StatusCode != 503 {
-		t.Errorf("Invalid status code: expecting '503', got '%d'", response.StatusCode)
-	}
-	response.Body.Close()
-
-	// Make healthy
-	h.Poll()
-
-	response, err = http.Get(address)
-	if err != nil {
-		t.Fatalf("Unable to query %s: %v", address, err)
-	}
-	if response.StatusCode != 200 {
-		t.Errorf("Invalid status code: expecting '200', got '%d'", response.StatusCode)
-	}
-	content, err := ioutil.ReadAll(response.Body)
-	if err != nil {
-		t.Fatalf("Unable to get response body from %s: %v", address, err)
-	}
-	response.Body.Close()
-
-	if string(content) != ok {
-		t.Errorf("Invalid response body: expecting 'OK', got '%s'", string(content))
-	}
-}
-*/
diff --git a/middleware/health/healther.go b/middleware/health/healther.go
deleted file mode 100644
index 1b794e03b..000000000
--- a/middleware/health/healther.go
+++ /dev/null
@@ -1,42 +0,0 @@
-package health
-
-// Healther interface needs to be implemented by each middleware willing to
-// provide healthhceck information to the health middleware. As a second step
-// the middleware needs to registered against the health middleware, by addding
-// it to healthers map. Note this method should return quickly, i.e. just
-// checking a boolean status, as it is called every second from the health
-// middleware.
-type Healther interface {
-	// Health returns a boolean indicating the health status of a middleware.
-	// False indicates unhealthy.
-	Health() bool
-}
-
-// Ok returns the global health status of all middleware configured in this server.
-func (h *health) Ok() bool {
-	h.RLock()
-	defer h.RUnlock()
-	return h.ok
-}
-
-// SetOk sets the global health status of all middleware configured in this server.
-func (h *health) SetOk(ok bool) {
-	h.Lock()
-	defer h.Unlock()
-	h.ok = ok
-}
-
-// poll polls all healthers and sets the global state.
-func (h *health) poll() {
-	for _, m := range h.h {
-		if !m.Health() {
-			h.SetOk(false)
-			return
-		}
-	}
-	h.SetOk(true)
-}
-
-// Middleware that implements the Healther interface.
-// TODO(miek): none yet.
-var healthers = map[string]bool{}
diff --git a/middleware/health/setup.go b/middleware/health/setup.go
deleted file mode 100644
index bf465bd74..000000000
--- a/middleware/health/setup.go
+++ /dev/null
@@ -1,73 +0,0 @@
-package health
-
-import (
-	"net"
-	"time"
-
-	"github.com/coredns/coredns/core/dnsserver"
-	"github.com/coredns/coredns/middleware"
-
-	"github.com/mholt/caddy"
-)
-
-func init() {
-	caddy.RegisterPlugin("health", caddy.Plugin{
-		ServerType: "dns",
-		Action:     setup,
-	})
-}
-
-func setup(c *caddy.Controller) error {
-	addr, err := healthParse(c)
-	if err != nil {
-		return middleware.Error("health", err)
-	}
-
-	h := &health{Addr: addr}
-
-	c.OnStartup(func() error {
-		for he := range healthers {
-			m := dnsserver.GetConfig(c).Handler(he)
-			if x, ok := m.(Healther); ok {
-				h.h = append(h.h, x)
-			}
-		}
-		return nil
-	})
-
-	c.OnStartup(func() error {
-		h.poll()
-		go func() {
-			for {
-				<-time.After(1 * time.Second)
-				h.poll()
-			}
-		}()
-		return nil
-	})
-
-	c.OnStartup(h.Startup)
-	c.OnFinalShutdown(h.Shutdown)
-
-	// Don't do AddMiddleware, as health is not *really* a middleware just a separate webserver running.
-	return nil
-}
-
-func healthParse(c *caddy.Controller) (string, error) {
-	addr := ""
-	for c.Next() {
-		args := c.RemainingArgs()
-
-		switch len(args) {
-		case 0:
-		case 1:
-			addr = args[0]
-			if _, _, e := net.SplitHostPort(addr); e != nil {
-				return "", e
-			}
-		default:
-			return "", c.ArgErr()
-		}
-	}
-	return addr, nil
-}
diff --git a/middleware/health/setup_test.go b/middleware/health/setup_test.go
deleted file mode 100644
index 87f4fc5fd..000000000
--- a/middleware/health/setup_test.go
+++ /dev/null
@@ -1,35 +0,0 @@
-package health
-
-import (
-	"testing"
-
-	"github.com/mholt/caddy"
-)
-
-func TestSetupHealth(t *testing.T) {
-	tests := []struct {
-		input     string
-		shouldErr bool
-	}{
-		{`health`, false},
-		{`health localhost:1234`, false},
-		{`health bla:a`, false},
-		{`health bla`, true},
-		{`health bla bla`, true},
-	}
-
-	for i, test := range tests {
-		c := caddy.NewTestController("dns", test.input)
-		_, err := healthParse(c)
-
-		if test.shouldErr && err == nil {
-			t.Errorf("Test %d: Expected error but found %s for input %s", i, err, test.input)
-		}
-
-		if err != nil {
-			if !test.shouldErr {
-				t.Errorf("Test %d: Expected no error but found one for input %s. Error was: %v", i, test.input, err)
-			}
-		}
-	}
-}