package httputils import ( "net/http" "strings" "github.com/Sirupsen/logrus" "github.com/docker/engine-api/types" "github.com/docker/engine-api/types/versions" "github.com/gorilla/mux" "google.golang.org/grpc" ) // httpStatusError is an interface // that errors with custom status codes // implement to tell the api layer // which response status to set. type httpStatusError interface { HTTPErrorStatusCode() int } // inputValidationError is an interface // that errors generated by invalid // inputs can implement to tell the // api layer to set a 400 status code // in the response. type inputValidationError interface { IsValidationError() bool } // GetHTTPErrorStatusCode retrieve status code from error message func GetHTTPErrorStatusCode(err error) int { if err == nil { logrus.WithFields(logrus.Fields{"error": err}).Error("unexpected HTTP error handling") return http.StatusInternalServerError } var statusCode int errMsg := err.Error() switch e := err.(type) { case httpStatusError: statusCode = e.HTTPErrorStatusCode() case inputValidationError: statusCode = http.StatusBadRequest default: // FIXME: this is brittle and should not be necessary, but we still need to identify if // there are errors falling back into this logic. // If we need to differentiate between different possible error types, // we should create appropriate error types that implement the httpStatusError interface. errStr := strings.ToLower(errMsg) for keyword, status := range map[string]int{ "not found": http.StatusNotFound, "no such": http.StatusNotFound, "bad parameter": http.StatusBadRequest, "no command": http.StatusBadRequest, "conflict": http.StatusConflict, "impossible": http.StatusNotAcceptable, "wrong login/password": http.StatusUnauthorized, "unauthorized": http.StatusUnauthorized, "hasn't been activated": http.StatusForbidden, "this node": http.StatusNotAcceptable, } { if strings.Contains(errStr, keyword) { statusCode = status break } } } if statusCode == 0 { statusCode = http.StatusInternalServerError } return statusCode } // MakeErrorHandler makes an HTTP handler that decodes a Docker error and // returns it in the response. func MakeErrorHandler(err error) http.HandlerFunc { return func(w http.ResponseWriter, r *http.Request) { statusCode := GetHTTPErrorStatusCode(err) vars := mux.Vars(r) if vars["version"] == "" || versions.GreaterThan(vars["version"], "1.23") { response := &types.ErrorResponse{ Message: err.Error(), } WriteJSON(w, statusCode, response) } else { http.Error(w, grpc.ErrorDesc(err), statusCode) } } }