moby/api/server/middleware/debug.go

package middleware

import (
	"bufio"
	"encoding/json"
	"io"
	"net/http"

	"github.com/Sirupsen/logrus"
	"github.com/docker/docker/api/server/httputils"
	"github.com/docker/docker/pkg/ioutils"
	"golang.org/x/net/context"
)

// DebugRequestMiddleware dumps the request to logger
func DebugRequestMiddleware(handler httputils.APIFunc) httputils.APIFunc {
	return func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
		logrus.Debugf("%s %s", r.Method, r.RequestURI)

		if r.Method != "POST" {
			return handler(ctx, w, r, vars)
		}
		if err := httputils.CheckForJSON(r); err != nil {
			return handler(ctx, w, r, vars)
		}
		maxBodySize := 4096 // 4KB
		if r.ContentLength > int64(maxBodySize) {
			return handler(ctx, w, r, vars)
		}

		body := r.Body
		bufReader := bufio.NewReaderSize(body, maxBodySize)
		r.Body = ioutils.NewReadCloserWrapper(bufReader, func() error { return body.Close() })

		b, err := bufReader.Peek(maxBodySize)
		if err != io.EOF {
			// either there was an error reading, or the buffer is full (in which case the request is too large)
			return handler(ctx, w, r, vars)
		}

		var postForm map[string]interface{}
		if err := json.Unmarshal(b, &postForm); err == nil {
			if _, exists := postForm["password"]; exists {
				postForm["password"] = "*****"
			}
			formStr, errMarshal := json.Marshal(postForm)
			if errMarshal == nil {
				logrus.Debugf("form data: %s", string(formStr))
			} else {
				logrus.Debugf("form data: %q", postForm)
			}
		}

		return handler(ctx, w, r, vars)
	}
}