Golang errors.Error類代碼示例

// commonLogHandler will log to w using the Apache common log format
// http://httpd.apache.org/docs/2.2/logs.html#common
// If w is nil, nothing will be logged
func commonLoggerMiddleware(w io.Writer) Middleware {
	return func(ep *Endpoint, h Handler) Handler {
		// If no writer is passed to middleware just return the handler
		if w == nil {
			return h
		}

		return func(req *Request) (proto.Message, errors.Error) {
			var userId string
			if req.Auth() != nil && req.Auth().AuthUser() != nil {
				userId = req.Auth().AuthUser().Id
			}

			var err errors.Error
			var m proto.Message

			// In defer in case the handler panics
			defer func() {
				status := uint32(200)
				if err != nil {
					status = err.HttpCode()
				}

				size := 0
				if m != nil {
					log.Debug(m.String())
					size = len(m.String())
				}

				fmt.Fprintf(w, "%s - %s [%s] \"%s %s %s\" %d %d\n",
					req.From(),
					userId,
					time.Now().Format("02/Jan/2006:15:04:05 -0700"),
					"GET", // Treat them all as GET's at the moment
					req.Endpoint(),
					"HTTP/1.0", // Has to be HTTP or apachetop ignores it
					status,
					size,
				)
			}()

			// Execute the actual handler
			m, err = h(req)
			return m, err
		}
	}
}

// traceRsp decides if we want to trigger a trace event (when processing response) and if so deals with it
func (c *client) traceRsp(req *Request, rsp *Response, err errors.Error, d time.Duration) {
	if req.shouldTrace() {
		e := &traceproto.Event{
			Timestamp:       proto.Int64(time.Now().UnixNano()),
			TraceId:         proto.String(req.TraceID()),
			Type:            traceproto.Event_REP.Enum(),
			MessageId:       proto.String(req.MessageID()),
			From:            proto.String(req.From()),
			FromEndpoint:    proto.String(req.FromEndpoint()),
			To:              proto.String(fmt.Sprintf("%v.%v", req.Service(), req.Endpoint())),
			ParentMessageId: proto.String(req.ParentMessageID()),
			Hostname:        proto.String(c.hostname),
			Az:              proto.String(c.az),
			Payload:         proto.String(""), // @todo
			Duration:        proto.Int64(int64(d)),
			PersistentTrace: proto.Bool(req.TraceShouldPersist()),
		}
		if err != nil {
			e.ErrorCode = proto.String(err.Code())
			e.ErrorDescription = proto.String(err.Description())
		}
		trace.Send(e)
	}
}

// traceOut traces a request outbound from a service handler
func traceOut(req *Request, msg proto.Message, err errors.Error, d time.Duration) {
	if req.shouldTrace() {
		e := &traceproto.Event{
			Timestamp:         proto.Int64(time.Now().UnixNano()),
			TraceId:           proto.String(req.TraceID()),
			Type:              traceproto.Event_OUT.Enum(),
			MessageId:         proto.String(req.MessageID()),
			ParentMessageId:   proto.String(req.ParentMessageID()),
			From:              proto.String(req.From()),
			To:                proto.String(fmt.Sprintf("%v.%v", req.Service(), req.Endpoint())),
			Hostname:          proto.String(hostname),
			Az:                proto.String(az),
			Payload:           proto.String(""), // @todo
			HandlerInstanceId: proto.String(InstanceID),
			Duration:          proto.Int64(int64(d)),
			PersistentTrace:   proto.Bool(req.TraceShouldPersist()),
		}
		if err != nil {
			e.ErrorCode = proto.String(err.Code())
			e.ErrorDescription = proto.String(err.Description())
		}
		trace.Send(e)
	}
}

// publishError publishes an event when a handler returns an error
func publishError(req *Request, e errors.Error) {
	if !PublishErrors {
		return
	}

	stacktrace := ""
	if e.MultiStack() != nil {
		stacktrace = e.MultiStack().String()
	}

	application := ""
	if req.Auth().IsAuth() && req.Auth().AuthUser() != nil {
		application = req.Auth().AuthUser().Application()
	}
	userId := ""
	if req.Auth().IsAuth() && req.Auth().AuthUser() != nil {
		userId = req.Auth().AuthUser().Id
	}

	msg := map[string]interface{}{
		"created":     time.Now(),
		"service":     Name,
		"version":     Version,
		"azName":      az,
		"hostname":    hostname,
		"instanceId":  InstanceID,
		"error":       e.Error(),
		"type":        e.Type(),
		"code":        e.Code(),
		"description": e.Description(),
		"httpCode":    e.HttpCode(),
		"context":     e.Context(),
		"userId":      userId,
		"application": application,
		"traceId":     req.TraceID(),
		"stacktrace":  stacktrace,
	}

	payload, err := json.Marshal(msg)
	if err != nil {
		log.Errorf("[Server] Failed to JSON encode error event: %v", err)
	}
	if err = nsq.Publish(errorTopic, payload); err != nil {
		log.Errorf("[Server] Failed to publish error event: %v", err)
	}
}

// HandleRequest and send back response
func HandleRequest(req *Request) {
	defer func() {
		if r := recover(); r != nil {
			log.Criticalf("[Server] Panic \"%v\" when handling request: (id: %s, endpoint: %s, content-type: %s,"+
				" content-length: %d)", r, req.MessageID(), req.Destination(), req.delivery.ContentType,
				len(req.delivery.Body))
			inst.Counter(1.0, "runtime.panic", 1)
			publishFailure(r)
			debug.PrintStack()
		}
	}()

	if len(req.Service()) > 0 && req.Service() != Name {
		log.Criticalf(`[Server] Message meant for "%s" not "%s"`, req.Service(), Name)
		return
	}

reqProcessor:
	switch {
	case req.isHeartbeat():
		if dsc.IsConnected() {
			log.Tracef("[Server] Inbound heartbeat from: %s", req.ReplyTo())
			dsc.hb.beat()
			raven.SendResponse(PongResponse(req), InstanceID)
		} else {
			log.Warnf("[Server] Not connected but heartbeat from: %s", req.ReplyTo())
		}

	case req.IsPublication():
		log.Tracef("[Server] Inbound publication on topic: %s", req.Topic())

		if endpoint, ok := reg.find(req.Topic()); ok { // Match + call handler
			if data, err := endpoint.unmarshalRequest(req); err != nil {
				log.Warnf("[Server] Failed to unmarshal published message: %s", err.Error())
				break reqProcessor
			} else {
				req.unmarshaledData = data
			}

			if _, err := endpoint.Handler(req); err != nil {
				// don't do anything on error apart from log - it's a pub sub call so no response required
				log.Warnf("[Server] Failed to process published message: %v", err)
			}
		}

	default:
		log.Tracef("[Server] Inbound message %s from %s", req.MessageID(), req.ReplyTo())

		// Match a handler
		endpoint, ok := reg.find(req.Endpoint())
		if !ok {
			if rsp, err := ErrorResponse(req, errors.InternalServerError("com.hailocab.kernel.handler.missing", fmt.Sprintf("No handler registered for %s", req.Destination()))); err != nil {
				log.Criticalf("[Server] Unable to build response: %v", err)
			} else {
				raven.SendResponse(rsp, InstanceID)
			}
			return
		}

		// Unmarshal the request data
		var (
			reqData, rspData proto.Message
			err              errors.Error
		)
		if reqData, err = endpoint.unmarshalRequest(req); err == nil {
			req.unmarshaledData = reqData
		}

		// Call handler if no errors so far
		if err == nil {
			rspData, err = endpoint.Handler(req)
		}

		// Check response type matches what's registered
		if err == nil && rspData != nil {
			_, rspProtoT := endpoint.ProtoTypes()
			rspDataT := reflect.TypeOf(rspData)
			if rspProtoT != nil && rspProtoT != rspDataT {
				err = errors.InternalServerError("com.hailocab.kernel.server.mismatchedprotocol",
					fmt.Sprintf("Mismatched response protocol. %s != %s", rspDataT.String(), rspProtoT.String()))
			}
		}

		if err != nil {
			switch err.Type() {
			case errors.ErrorBadRequest, errors.ErrorForbidden, errors.ErrorNotFound:
				log.Debugf("[Server] Handler error %s calling %v.%v from %v: %v", err.Type(), req.Service(),
					req.Endpoint(), req.From(), err)
			case errors.ErrorInternalServer:
				go publishError(req, err)
				fallthrough
			default:
				log.Errorf("[Server] Handler error %s calling %v.%v from %v: %v", err.Type(), req.Service(),
					req.Endpoint(), req.From(), err)
			}

			if rsp, err := ErrorResponse(req, err); err != nil {
				log.Criticalf("[Server] Unable to build response: %v", err)
			} else {
//.........這裏部分代碼省略.........