Update callers of httputils.ReportError to specify message

go/httputils/http.go

 package httputils
 
 import (
         "bytes"
         "fmt"
         "io"
         "io/ioutil"
         "net"
         "net/http"
         "net/url"
@@ skipping 150 matching lines @@
         if err := backoff.RetryNotify(roundTripOp, backOffClient, notifyFunc); err != nil {
                 return nil, fmt.Errorf("HTTP request failed inspite of exponential backoff: %s", err)
         }
         return resp, nil
 }
 
 // TODO(stephana): Remove 'r' from the argument list since it's not used. It would
 // be also useful if we could specify a return status explicitly.
 
 // ReportError formats an HTTP error response and also logs the detailed error message.
+// The message parameter is returned in the HTTP response. If it is not provided then
+// "Unknown error" will be returned instead.
 func ReportError(w http.ResponseWriter, r *http.Request, err error, message string) {
         glog.Errorln(message, err)
         if err != io.ErrClosedPipe {
-                http.Error(w, message, 500)
+                httpErrMsg := message
+                if message == "" {
+                        httpErrMsg = "Unknown error"
+                }
+                http.Error(w, httpErrMsg, 500)
         }
 }
 
 // responseProxy implements http.ResponseWriter and records the status codes.
 type responseProxy struct {
         http.ResponseWriter
         wroteHeader bool
 }
 
 func (rp *responseProxy) WriteHeader(code int) {
@@ skipping 82 matching lines @@
                 val, err = strconv.Atoi(valStr)
                 if err != nil {
                         return 0, fmt.Errorf("Not a valid integer value.")
                 }
         }
         if val < 0 {
                 return defaultVal, nil
         }
         return val, nil
 }