func TestAfterRetryRefreshCreds(t *testing.T) {
	os.Clearenv()
	credProvider := &mockCredsProvider{}
	svc := NewService(&Config{Credentials: credentials.NewCredentials(credProvider), MaxRetries: 1})

	svc.Handlers.Clear()
	svc.Handlers.ValidateResponse.PushBack(func(r *Request) {
		r.Error = apierr.New("UnknownError", "", nil)
		r.HTTPResponse = &http.Response{StatusCode: 400}
	})
	svc.Handlers.UnmarshalError.PushBack(func(r *Request) {
		r.Error = apierr.New("ExpiredTokenException", "", nil)
	})
	svc.Handlers.AfterRetry.PushBack(func(r *Request) {
		AfterRetryHandler(r)
	})

	assert.True(t, svc.Config.Credentials.IsExpired(), "Expect to start out expired")
	assert.False(t, credProvider.retreiveCalled)

	req := NewRequest(svc, &Operation{Name: "Operation"}, nil, nil)
	req.Send()

	assert.True(t, svc.Config.Credentials.IsExpired())
	assert.False(t, credProvider.retreiveCalled)

	_, err := svc.Config.Credentials.Get()
	assert.NoError(t, err)
	assert.True(t, credProvider.retreiveCalled)
}

// loadProfiles loads from the file pointed to by shared credentials filename for profile.
// The credentials retrieved from the profile will be returned or error. Error will be
// returned if it fails to read from the file, or the data is invalid.
func loadProfile(filename, profile string) (Value, error) {
	config, err := ini.LoadFile(filename)
	if err != nil {
		return Value{}, apierr.New("SharedCredsLoad", "failed to load shared credentials file", err)
	}
	iniProfile := config.Section(profile)

	id, ok := iniProfile["aws_access_key_id"]
	if !ok {
		return Value{}, apierr.New("SharedCredsAccessKey",
			fmt.Sprintf("shared credentials %s in %s did not contain aws_access_key_id", profile, filename),
			nil)
	}

	secret, ok := iniProfile["aws_secret_access_key"]
	if !ok {
		return Value{}, apierr.New("SharedCredsSecret",
			fmt.Sprintf("shared credentials %s in %s did not contain aws_secret_access_key", profile, filename),
			nil)
	}

	token := iniProfile["aws_session_token"]

	return Value{
		AccessKeyID:     id,
		SecretAccessKey: secret,
		SessionToken:    token,
	}, nil
}

func unmarshalError(req *Request) {
	bodyBytes, err := ioutil.ReadAll(req.HTTPResponse.Body)
	if err != nil {
		req.Error = apierr.New("UnmarshaleError", req.HTTPResponse.Status, err)
		return
	}
	if len(bodyBytes) == 0 {
		req.Error = apierr.NewRequestError(
			apierr.New("UnmarshaleError", req.HTTPResponse.Status, fmt.Errorf("empty body")),
			req.HTTPResponse.StatusCode,
			"",
		)
		return
	}
	var jsonErr jsonErrorResponse
	if err := json.Unmarshal(bodyBytes, &jsonErr); err != nil {
		req.Error = apierr.New("UnmarshaleError", "JSON unmarshal", err)
		return
	}
	req.Error = apierr.NewRequestError(
		apierr.New(jsonErr.Code, jsonErr.Message, nil),
		req.HTTPResponse.StatusCode,
		"",
	)
}

func TestChainProviderWithNoValidProvider(t *testing.T) {
	p := &ChainProvider{
		Providers: []Provider{
			&stubProvider{err: apierr.New("FirstError", "first provider error", nil)},
			&stubProvider{err: apierr.New("SecondError", "second provider error", nil)},
		},
	}

	assert.True(t, p.IsExpired(), "Expect expired with no providers")
	_, err := p.Retrieve()
	assert.Equal(t, ErrNoValidProvidersFoundInChain, err, "Expect no providers error returned")
}

// UnmarshalError unmarshals an error response for an AWS Query service.
func UnmarshalError(r *aws.Request) {
	defer r.HTTPResponse.Body.Close()

	resp := &xmlErrorResponse{}
	err := xml.NewDecoder(r.HTTPResponse.Body).Decode(resp)
	if err != nil && err != io.EOF {
		r.Error = apierr.New("Unmarshal", "failed to decode query XML error response", err)
	} else {
		r.Error = apierr.NewRequestError(
			apierr.New(resp.Code, resp.Message, nil),
			r.HTTPResponse.StatusCode,
			resp.RequestID,
		)
	}
}

// Retrieve retrieves credentials from the EC2 service.
// Error will be returned if the request fails, or unable to extract
// the desired credentials.
func (m *EC2RoleProvider) Retrieve() (Value, error) {
	if m.Client == nil {
		m.Client = http.DefaultClient
	}
	if m.Endpoint == "" {
		m.Endpoint = metadataCredentialsEndpoint
	}

	credsList, err := requestCredList(m.Client, m.Endpoint)
	if err != nil {
		return Value{}, err
	}

	if len(credsList) == 0 {
		return Value{}, apierr.New("EmptyEC2RoleList", "empty EC2 Role list", nil)
	}
	credsName := credsList[0]

	roleCreds, err := requestCred(m.Client, m.Endpoint, credsName)
	if err != nil {
		return Value{}, err
	}

	m.expiresOn = roleCreds.Expiration
	if m.ExpiryWindow > 0 {
		// Offset based on expiry window if set.
		m.expiresOn = m.expiresOn.Add(-m.ExpiryWindow)
	}

	return Value{
		AccessKeyID:     roleCreds.AccessKeyID,
		SecretAccessKey: roleCreds.SecretAccessKey,
		SessionToken:    roleCreds.Token,
	}, nil
}

// SendHandler is a request handler to send service request using HTTP client.
func SendHandler(r *Request) {
	var err error
	r.HTTPResponse, err = r.Service.Config.HTTPClient.Do(r.HTTPRequest)
	if err != nil {
		// Capture the case where url.Error is returned for error processing
		// response. e.g. 301 without location header comes back as string
		// error and r.HTTPResponse is nil. Other url redirect errors will
		// comeback in a similar method.
		if e, ok := err.(*url.Error); ok {
			if s := reStatusCode.FindStringSubmatch(e.Error()); s != nil {
				code, _ := strconv.ParseInt(s[1], 10, 64)
				r.HTTPResponse = &http.Response{
					StatusCode: int(code),
					Status:     http.StatusText(int(code)),
					Body:       ioutil.NopCloser(bytes.NewReader([]byte{})),
				}
				return
			}
		}
		if r.HTTPRequest == nil {
			// Add a dummy request response object to ensure the HTTPResponse
			// value is consistent.
			r.HTTPResponse = &http.Response{
				StatusCode: int(0),
				Status:     http.StatusText(int(0)),
				Body:       ioutil.NopCloser(bytes.NewReader([]byte{})),
			}
		}
		// Catch all other request errors.
		r.Error = apierr.New("RequestError", "send request failed", err)
		r.Retryable.Set(true) // network errors are retryable
	}
}

func buildHeader(r *aws.Request, v reflect.Value, name string) {
	str, err := convertType(v)
	if err != nil {
		r.Error = apierr.New("Marshal", "failed to encode REST request", err)
	} else if str != nil {
		r.HTTPRequest.Header.Add(name, *str)
	}
}

func buildQueryString(r *aws.Request, v reflect.Value, name string, query url.Values) {
	str, err := convertType(v)
	if err != nil {
		r.Error = apierr.New("Marshal", "failed to encode REST request", err)
	} else if str != nil {
		query.Set(name, *str)
	}
}

// requestCred requests the credentials for a specific credentials from the EC2 service.
//
// If the credentials cannot be found, or there is an error reading the response
// and error will be returned.
func requestCred(client *http.Client, endpoint, credsName string) (*ec2RoleCredRespBody, error) {
	resp, err := client.Get(endpoint + credsName)
	if err != nil {
		return nil, apierr.New("GetEC2RoleCredentials",
			fmt.Sprintf("failed to get %s EC2 Role credentials", credsName),
			err)
	}
	defer resp.Body.Close()

	respCreds := &ec2RoleCredRespBody{}
	if err := json.NewDecoder(resp.Body).Decode(respCreds); err != nil {
		return nil, apierr.New("DecodeEC2RoleCredentials",
			fmt.Sprintf("failed to decode %s EC2 Role credentials", credsName),
			err)
	}

	return respCreds, nil
}

func buildHeaderMap(r *aws.Request, v reflect.Value, prefix string) {
	for _, key := range v.MapKeys() {
		str, err := convertType(v.MapIndex(key))
		if err != nil {
			r.Error = apierr.New("Marshal", "failed to encode REST request", err)
		} else if str != nil {
			r.HTTPRequest.Header.Add(prefix+key.String(), *str)
		}
	}
}

// requestCredList requests a list of credentials from the EC2 service.
// If there are no credentials, or there is an error making or receiving the request
func requestCredList(client *http.Client, endpoint string) ([]string, error) {
	resp, err := client.Get(endpoint)
	if err != nil {
		return nil, apierr.New("ListEC2Role", "failed to list EC2 Roles", err)
	}
	defer resp.Body.Close()

	credsList := []string{}
	s := bufio.NewScanner(resp.Body)
	for s.Scan() {
		credsList = append(credsList, s.Text())
	}

	if err := s.Err(); err != nil {
		return nil, apierr.New("ReadEC2Role", "failed to read list of EC2 Roles", err)
	}

	return credsList, nil
}

func buildURI(r *aws.Request, v reflect.Value, name string) {
	value, err := convertType(v)
	if err != nil {
		r.Error = apierr.New("Marshal", "failed to encode REST request", err)
	} else if value != nil {
		uri := r.HTTPRequest.URL.Path
		uri = strings.Replace(uri, "{"+name+"}", EscapePath(*value, true), -1)
		uri = strings.Replace(uri, "{"+name+"+}", EscapePath(*value, false), -1)
		r.HTTPRequest.URL.Path = uri
	}
}

// Unmarshal unmarshals a response for an AWS Query service.
func Unmarshal(r *aws.Request) {
	defer r.HTTPResponse.Body.Close()
	if r.DataFilled() {
		decoder := xml.NewDecoder(r.HTTPResponse.Body)
		err := xmlutil.UnmarshalXML(r.Data, decoder, r.Operation.Name+"Result")
		if err != nil {
			r.Error = apierr.New("Unmarshal", "failed decoding Query response", err)
			return
		}
	}
}

func TestChainProviderGet(t *testing.T) {
	p := &ChainProvider{
		Providers: []Provider{
			&stubProvider{err: apierr.New("FirstError", "first provider error", nil)},
			&stubProvider{err: apierr.New("SecondError", "second provider error", nil)},
			&stubProvider{
				creds: Value{
					AccessKeyID:     "AKID",
					SecretAccessKey: "SECRET",
					SessionToken:    "",
				},
			},
		},
	}

	creds, err := p.Retrieve()
	assert.Nil(t, err, "Expect no error")
	assert.Equal(t, "AKID", creds.AccessKeyID, "Expect access key ID to match")
	assert.Equal(t, "SECRET", creds.SecretAccessKey, "Expect secret access key to match")
	assert.Empty(t, creds.SessionToken, "Expect session token to be empty")
}

// ValidateParameters is a request handler to validate the input parameters.
// Validating parameters only has meaning if done prior to the request being sent.
func ValidateParameters(r *Request) {
	if r.ParamsFilled() {
		v := validator{errors: []string{}}
		v.validateAny(reflect.ValueOf(r.Params), "")

		if count := len(v.errors); count > 0 {
			format := "%d validation errors:\n- %s"
			msg := fmt.Sprintf(format, count, strings.Join(v.errors, "\n- "))
			r.Error = apierr.New("InvalidParameter", msg, nil)
		}
	}
}

func unmarshalBody(r *aws.Request, v reflect.Value) {
	if field, ok := v.Type().FieldByName("SDKShapeTraits"); ok {
		if payloadName := field.Tag.Get("payload"); payloadName != "" {
			pfield, _ := v.Type().FieldByName(payloadName)
			if ptag := pfield.Tag.Get("type"); ptag != "" && ptag != "structure" {
				payload := v.FieldByName(payloadName)
				if payload.IsValid() {
					switch payload.Interface().(type) {
					case []byte:
						b, err := ioutil.ReadAll(r.HTTPResponse.Body)
						if err != nil {
							r.Error = apierr.New("Unmarshal", "failed to decode REST response", err)
						} else {
							payload.Set(reflect.ValueOf(b))
						}
					case *string:
						b, err := ioutil.ReadAll(r.HTTPResponse.Body)
						if err != nil {
							r.Error = apierr.New("Unmarshal", "failed to decode REST response", err)
						} else {
							str := string(b)
							payload.Set(reflect.ValueOf(&str))
						}
					default:
						switch payload.Type().String() {
						case "io.ReadSeeker":
							payload.Set(reflect.ValueOf(aws.ReadSeekCloser(r.HTTPResponse.Body)))
						case "aws.ReadSeekCloser", "io.ReadCloser":
							payload.Set(reflect.ValueOf(r.HTTPResponse.Body))
						default:
							r.Error = apierr.New("Unmarshal",
								"failed to decode REST response",
								fmt.Errorf("unknown payload type %s", payload.Type()))
						}
					}
				}
			}
		}
	}
}

func unmarshalLocationElements(r *aws.Request, v reflect.Value) {
	for i := 0; i < v.NumField(); i++ {
		m, field := v.Field(i), v.Type().Field(i)
		if n := field.Name; n[0:1] == strings.ToLower(n[0:1]) {
			continue
		}

		if m.IsValid() {
			name := field.Tag.Get("locationName")
			if name == "" {
				name = field.Name
			}

			switch field.Tag.Get("location") {
			case "statusCode":
				unmarshalStatusCode(m, r.HTTPResponse.StatusCode)
			case "header":
				err := unmarshalHeader(m, r.HTTPResponse.Header.Get(name))
				if err != nil {
					r.Error = apierr.New("Unmarshal", "failed to decode REST response", err)
					break
				}
			case "headers":
				prefix := field.Tag.Get("locationName")
				err := unmarshalHeaderMap(m, r.HTTPResponse.Header, prefix)
				if err != nil {
					r.Error = apierr.New("Unmarshal", "failed to decode REST response", err)
					break
				}
			}
		}
		if r.Error != nil {
			return
		}
	}
}

// Build builds a request for an AWS Query service.
func Build(r *aws.Request) {
	body := url.Values{
		"Action":  {r.Operation.Name},
		"Version": {r.Service.APIVersion},
	}
	if err := queryutil.Parse(body, r.Params, false); err != nil {
		r.Error = apierr.New("Marshal", "failed encoding Query request", err)
		return
	}

	if r.ExpireTime == 0 {
		r.HTTPRequest.Method = "POST"
		r.HTTPRequest.Header.Set("Content-Type", "application/x-www-form-urlencoded; charset=utf-8")
		r.SetBufferBody([]byte(body.Encode()))
	} else { // This is a pre-signed request
		r.HTTPRequest.Method = "GET"
		r.HTTPRequest.URL.RawQuery = body.Encode()
	}
}

func buildBody(r *aws.Request, v reflect.Value) {
	if field, ok := v.Type().FieldByName("SDKShapeTraits"); ok {
		if payloadName := field.Tag.Get("payload"); payloadName != "" {
			pfield, _ := v.Type().FieldByName(payloadName)
			if ptag := pfield.Tag.Get("type"); ptag != "" && ptag != "structure" {
				payload := reflect.Indirect(v.FieldByName(payloadName))
				if payload.IsValid() && payload.Interface() != nil {
					switch reader := payload.Interface().(type) {
					case io.ReadSeeker:
						r.SetReaderBody(reader)
					case []byte:
						r.SetBufferBody(reader)
					case string:
						r.SetStringBody(reader)
					default:
						r.Error = apierr.New("Marshal",
							"failed to encode REST request",
							fmt.Errorf("unknown payload type %s", payload.Type()))
					}
				}
			}
		}
	}
}