error.go

/*
Copyright 2016 The Fission Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package fission

import (
	"fmt"
	"io/ioutil"
	"net/http"
	"strings"
)

func (err Error) Error() string {
	return fmt.Sprintf("%v - %v", err.Description(), err.Message)
}

func MakeError(code int, msg string) Error {
	return Error{Code: errorCode(code), Message: msg}
}

func MakeErrorFromHTTP(resp *http.Response) error {
	if resp.StatusCode == http.StatusOK {
		return nil
	}

	var errCode int
	switch resp.StatusCode {
	case http.StatusBadRequest:
		errCode = ErrorInvalidArgument
	case http.StatusForbidden:
		errCode = ErrorNotAuthorized
	case http.StatusNotFound:
		errCode = ErrorNotFound
	case http.StatusConflict:
		errCode = ErrorNameExists
	default:
		errCode = ErrorInternal
	}

	msg := resp.Status
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)
	if err == nil && len(body) > 0 {
		msg = strings.TrimSpace(string(body))
	}

	return MakeError(errCode, msg)
}

func (err Error) HTTPStatus() int {
	var code int
	switch err.Code {
	case ErrorInvalidArgument:
		code = http.StatusBadRequest
	case ErrorNotAuthorized:
		code = http.StatusForbidden
	case ErrorNotFound:
		code = http.StatusNotFound
	case ErrorNameExists:
		code = http.StatusConflict
	default:
		code = http.StatusInternalServerError
	}
	return code
}

func GetHTTPError(err error) (int, string) {
	var msg string
	var code int
	fe, ok := err.(Error)
	if ok {
		code = fe.HTTPStatus()
		msg = fe.Message
	} else {
		code = http.StatusInternalServerError
		msg = err.Error()
	}
	return code, msg
}

func (err Error) Description() string {
	idx := int(err.Code)
	if idx < 0 || idx > len(errorDescriptions)-1 {
		return ""
	}
	return errorDescriptions[idx]
}