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

1 files changed, 79 insertions, 0 deletions

diff --git a/plugin/errors/errors.go b/plugin/errors/errors.go
new file mode 100644
index 000000000..a313f2e0d
--- /dev/null
+++ b/plugin/errors/errors.go
@@ -0,0 +1,79 @@
+// Package errors implements an HTTP error handling plugin.
+package errors
+
+import (
+	"fmt"
+	"log"
+	"runtime"
+	"strings"
+	"time"
+
+	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/request"
+
+	"github.com/miekg/dns"
+	"golang.org/x/net/context"
+)
+
+// errorHandler handles DNS errors (and errors from other plugin).
+type errorHandler struct {
+	Next    plugin.Handler
+	LogFile string
+	Log     *log.Logger
+}
+
+// ServeDNS implements the plugin.Handler interface.
+func (h errorHandler) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
+	defer h.recovery(ctx, w, r)
+
+	rcode, err := plugin.NextOrFailure(h.Name(), h.Next, ctx, w, r)
+
+	if err != nil {
+		state := request.Request{W: w, Req: r}
+		errMsg := fmt.Sprintf("%s [ERROR %d %s %s] %v", time.Now().Format(timeFormat), rcode, state.Name(), state.Type(), err)
+
+		h.Log.Println(errMsg)
+	}
+
+	return rcode, err
+}
+
+func (h errorHandler) Name() string { return "errors" }
+
+func (h errorHandler) recovery(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) {
+	rec := recover()
+	if rec == nil {
+		return
+	}
+
+	// Obtain source of panic
+	// From: https://gist.github.com/swdunlop/9629168
+	var name, file string // function name, file name
+	var line int
+	var pc [16]uintptr
+	n := runtime.Callers(3, pc[:])
+	for _, pc := range pc[:n] {
+		fn := runtime.FuncForPC(pc)
+		if fn == nil {
+			continue
+		}
+		file, line = fn.FileLine(pc)
+		name = fn.Name()
+		if !strings.HasPrefix(name, "runtime.") {
+			break
+		}
+	}
+
+	// Trim file path
+	delim := "/coredns/"
+	pkgPathPos := strings.Index(file, delim)
+	if pkgPathPos > -1 && len(file) > pkgPathPos+len(delim) {
+		file = file[pkgPathPos+len(delim):]
+	}
+
+	panicMsg := fmt.Sprintf("%s [PANIC %s %s] %s:%d - %v", time.Now().Format(timeFormat), r.Question[0].Name, dns.Type(r.Question[0].Qtype), file, line, rec)
+	// Currently we don't use the function name, since file:line is more conventional
+	h.Log.Printf(panicMsg)
+}
+
+const timeFormat = "02/Jan/2006:15:04:05 -0700"