Adds recovery middleware

2015-08-12 16:31:14 +02:00
parent 4d26150fb0
commit 8d3675fcfb
1 changed files with 69 additions and 0 deletions
--- a/recovery.go
+++ b/recovery.go
@@ -0,0 +1,69 @@
+package narco
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"runtime"
+
+	"github.com/codemodus/chain"
+	"golang.org/x/net/context"
+)
+
+type StackResponseFormatter func(w io.Writer, err interface{}, stack []byte)
+
+func GoFormatStack(w io.Writer, err interface{}, stack []byte) {
+	fmt.Fprintf(w, "Server internal error: %s\n%s", err, stack)
+}
+
+func HtmlFormatStack(w io.Writer, err interface{}, stack []byte) {
+	fmt.Fprintf(w, `<html>
+  <body>
+    <h1>Server internal error: %s</h1>
+    <pre>%s</pre>
+  </body>
+</html>`, err, stack)
+}
+
+type Recoverer struct {
+	Logger              *log.Logger
+	ShowStackInResponse StackResponseFormatter
+	StackOtherGoroutine bool
+}
+
+func NewRecoverer() *Recoverer {
+	return &Recoverer{
+		Logger:              log.New(os.Stdout, "[narco] ", log.LstdFlags),
+		ShowStackInResponse: nil,
+		StackOtherGoroutine: false,
+	}
+}
+
+func (rec *Recoverer) Wrap() func(chain.Handler) chain.Handler {
+	return func(other chain.Handler) chain.Handler {
+		return chain.HandlerFunc(func(ctx context.Context, h http.ResponseWriter, req *http.Request) {
+			defer func() {
+				err := recover()
+				if err == nil {
+					return
+				}
+				//				h.Header()["Content-Type"] = []string{"text/html; charset=utf-8"}
+				h.WriteHeader(http.StatusInternalServerError)
+
+				stack := make([]byte, 8*1024)
+				stack = stack[:runtime.Stack(stack, rec.StackOtherGoroutine)]
+				rec.Logger.Printf("PANIC: %s\n%s", err, stack)
+
+				if rec.ShowStackInResponse != nil {
+					rec.ShowStackInResponse(h, err, stack)
+				} else {
+					fmt.Fprintf(h, "%s\n", http.StatusText(http.StatusInternalServerError))
+				}
+			}()
+
+			other.ServeHTTPContext(ctx, h, req)
+		})
+	}
+}