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本文次要钻研一下dubbo-go的AccessLogFilter
AccessLogFilter
dubbo-go-v1.4.2/filter/filter_impl/access_log_filter.go
type AccessLogFilter struct { logChan chan AccessLogData}- AccessLogFilter定义了AccessLogData类型的chan
Invoke
dubbo-go-v1.4.2/filter/filter_impl/access_log_filter.go
func (ef *AccessLogFilter) Invoke(ctx context.Context, invoker protocol.Invoker, invocation protocol.Invocation) protocol.Result { accessLog := invoker.GetUrl().GetParam(constant.ACCESS_LOG_KEY, "") if len(accessLog) > 0 { accessLogData := AccessLogData{data: ef.buildAccessLogData(invoker, invocation), accessLog: accessLog} ef.logIntoChannel(accessLogData) } return invoker.Invoke(ctx, invocation)}- Invoke办法首先通过invoker.GetUrl().GetParam获取constant.ACCESS_LOG_KEY配置，若accessLog有值，则通过ef.buildAccessLogData构建accessLogData，而后执行ef.logIntoChannel(accessLogData)，最初执行invoker.Invoke(ctx, invocation)
logIntoChannel
dubbo-go-v1.4.2/filter/filter_impl/access_log_filter.go
func (ef *AccessLogFilter) logIntoChannel(accessLogData AccessLogData) { select { case ef.logChan <- accessLogData: return default: logger.Warn("The channel is full and the access logIntoChannel data will be dropped") return }}- logIntoChannel办法通过select办法将accessLogData写入ef.logChan
buildAccessLogData
dubbo-go-v1.4.2/filter/filter_impl/access_log_filter.go
func (ef *AccessLogFilter) buildAccessLogData(_ protocol.Invoker, invocation protocol.Invocation) map[string]string { dataMap := make(map[string]string, 16) attachments := invocation.Attachments() dataMap[constant.INTERFACE_KEY] = attachments[constant.INTERFACE_KEY] dataMap[constant.METHOD_KEY] = invocation.MethodName() dataMap[constant.VERSION_KEY] = attachments[constant.VERSION_KEY] dataMap[constant.GROUP_KEY] = attachments[constant.GROUP_KEY] dataMap[constant.TIMESTAMP_KEY] = time.Now().Format(MessageDateLayout) dataMap[constant.LOCAL_ADDR], _ = attachments[constant.LOCAL_ADDR] dataMap[constant.REMOTE_ADDR], _ = attachments[constant.REMOTE_ADDR] if len(invocation.Arguments()) > 0 { builder := strings.Builder{} // todo(after the paramTypes were set to the invocation. we should change this implementation) typeBuilder := strings.Builder{} builder.WriteString(reflect.ValueOf(invocation.Arguments()[0]).String()) typeBuilder.WriteString(reflect.TypeOf(invocation.Arguments()[0]).Name()) for idx := 1; idx < len(invocation.Arguments()); idx++ { arg := invocation.Arguments()[idx] builder.WriteString(",") builder.WriteString(reflect.ValueOf(arg).String()) typeBuilder.WriteString(",") typeBuilder.WriteString(reflect.TypeOf(arg).Name()) } dataMap[Arguments] = builder.String() dataMap[Types] = typeBuilder.String() } return dataMap}- buildAccessLogData办法提取invocation.Attachments()的数据来构建dataMap
writeLogToFile
dubbo-go-v1.4.2/filter/filter_impl/access_log_filter.go
func (ef *AccessLogFilter) writeLogToFile(data AccessLogData) { accessLog := data.accessLog if isDefault(accessLog) { logger.Info(data.toLogMessage()) return } logFile, err := ef.openLogFile(accessLog) if err != nil { logger.Warnf("Can not open the access log file: %s, %v", accessLog, err) return } logger.Debugf("Append log to %s", accessLog) message := data.toLogMessage() message = message + "\n" _, err = logFile.WriteString(message) if err != nil { logger.Warnf("Can not write the log into access log file: %s, %v", accessLog, err) }}- writeLogToFile办法通过logFile.WriteString(message)将log写到文件
GetAccessLogFilter
dubbo-go-v1.4.2/filter/filter_impl/access_log_filter.go
func GetAccessLogFilter() filter.Filter { accessLogFilter := &AccessLogFilter{logChan: make(chan AccessLogData, LogMaxBuffer)} go func() { for accessLogData := range accessLogFilter.logChan { accessLogFilter.writeLogToFile(accessLogData) } }() return accessLogFilter}- GetAccessLogFilter办法会创立AccessLogFilter，同时异步遍历accessLogFilter.logChan执行accessLogFilter.writeLogToFile(accessLogData)
小结
AccessLogFilter定义了AccessLogData类型的chan；Invoke办法首先通过invoker.GetUrl().GetParam获取constant.ACCESS_LOG_KEY配置，若accessLog有值，则通过ef.buildAccessLogData构建accessLogData，而后执行ef.logIntoChannel(accessLogData)，最初执行invoker.Invoke(ctx, invocation)
doc
- access_log_filter