Python - 相对导入(Python - Relative import)

 更新： 
 
 感谢您的澄清，我更了解您的目标。 您希望从IParameterInspector实现记录的消息反映“Example.MyService.GetContacts”的调用站点，其中Example.MyService是您的服务（由instanceType参数指示），“GetContacts”是操作。 您可以手动合成呼叫站点信息。 你仍然会使用NLog的Logger.Log方法，你仍然可以创建一个LogEventInfo对象。 此外，您可以在LogEventInfo.Properties对象中存储“class”和“method”。 而不是基于instanceType（即服务）检索记录器（来自LogManager），而不是根据参数检查器的类型（在您的情况下为NLogLogger）检索记录器。 最后，您可以向NLog.config添加其他规则（并将其应用于NLogLogger类型），以便该规则具有不同的日志记录格式。 您将手动将包含调用站点信息（存储在LogEventInfo.Properties集合中）的日志记录格式的字段添加到与其他日志记录规则配置中的“真实”调用点LayoutRenderer相同的位置。 
 
 接下来，我将发布一个新版本的NLogLogger实现，它完成了我上面描述的内容。 
 
public class NLogLogger : IParameterInspector
{
    private static readonly NLog.Logger logger = LogManager.GetCurrentClassLogger();

    private void Log(Type instanceType, string operationName, string msg)
    {
        NLog.Logger serviceLogger = LogManager.GetLogger(
            instanceType.FullName, instanceType);

        //Create LogEventInfo with the Logger.Name from the logger associated with the service
        LogEventInfo le = new LogEventInfo(LogLevel.Info, serviceLogger.Name, msg);
        le.Properties.Add("fakecallsite", string.Format("{0}.{1}",instanceType.ToString(),operationName);

        //Log the message using the parameter inspector's logger.
        logger.Log(typeof(NLogLogger), le);
    }

    public object BeforeCall(string operationName, object[] inputs)
    {
        // Retrieve the service instance type for the logger then log the call.
        OperationContext operationContext = OperationContext.Current;
        Type instanceType = operationContext.InstanceContext
            .GetServiceInstance().GetType();
        Log(instanceType, operationName, "BeforeCall");

        return instanceType;
    }

    public void AfterCall(
        string operationName, object[] outputs,
        object returnValue, object correlationState
    )
    {
        if (correlationState is Type)
            Log(correlationState, operationName, "AfterCall");
    }
}
 
 您的NLog.config将具有类似的规则。 一条规则专门针对您的NLogLogger参数检查器。 它记录到“f1”并且是“最终”规则，这意味着来自参数检查器的记录消息不会被任何其他规则记录。 另一个规则适用于所有其他记录器。 每个都记录到不同的文件目标，但两个文件目标都写入同一个文件（我认为这是有效的）。 关键是每个文件都有自己的布局。 
 
<logger name="Your.Full.NameSpace.NLogLogger" minlevel="*" writeTo="f1" final="true" /> 
<logger name="*" minlevel="*" writeTo="f2" /> 
 
 你的目标和布局看起来像这样。 我们正在定义一个变量，其值是EventPropertiesLayoutRenderer的值，它是我们存储在LogEventInfo.Properties [“fakecallsite”]中的虚假调用站点。 
 
  <variable name="fakecallsite" value="${event-properties:fakecallsite}"/>
  <variable name="f1layout" value="${longdate} | ${level} | ${logger} | ${fakecallsite} | ${message}"/>
  <variable name="f2layout" value="${longdate} | ${level} | ${logger} | ${callsite} | ${message}"/>
  <targets>
    <target name="f1" xsi:type="File" layout="${f1layout}" fileName="${basedir}/${shortdate}.log" />
    <target name="f2" xsi:type="File" layout="${f2layout}" fileName="${basedir}/${shortdate}.log"        />
  </targets>
 
 请注意，我没有尝试过这个，但我认为它应该可以工作（或者应该足够接近，你可以使它工作）。 一个限制是，由于我们正在计算虚假呼叫站点，我们不能使用真实的呼叫站点LayoutRenderer来操纵输出中的fakecallsite字段的内容。 如果这很重要，可以通过单独存储类和方法（在LogEventInfo.Properties中）然后在NLog.config中设置“fakecallsite”变量来包含类，方法或两者来模拟它。 
 
 结束更新 
 
 您的包装器应该使用Log方法。 此外，传递给NLog Logger.Log方法的类型应该是NLog Logger包装器的类型，而不是服务实例类型的类型。 您仍然可以使用服务实例的类型来检索正确的Logger实例。 它应该看起来像这样： 
 
public class NLogLogger : IParameterInspector
{
    private void Log(Type instanceType, string operationName, string msg)
    {
        NLog.Logger logger = LogManager.GetLogger(
            instanceType.FullName, instanceType);

        //This is the key to preserving the call site in a wrapper.  Create a LogEventInfo
        //then use NLog's Logger.Log method to log the message, passing the type of your 
        //wrapper as the first argument.

        LogEventInfo le = new LogEventInfo(LogLevel.Info, logger.Name, msg);
        logger.Log(typeof(NLogLogger), le);
    }

    public object BeforeCall(string operationName, object[] inputs)
    {
        // Retrieve the service instance type for the logger then log the call.
        OperationContext operationContext = OperationContext.Current;
        Type instanceType = operationContext.InstanceContext
            .GetServiceInstance().GetType();
        Log(instanceType, operationName, "BeforeCall");

        return instanceType;
    }

    public void AfterCall(
        string operationName, object[] outputs,
        object returnValue, object correlationState
    )
    {
        if (correlationState is Type)
            Log(correlationState, operationName, "AfterCall");
    }
}

UPDATE:
 
Thanks to your clarification, I better understand what you are trying to do. You would like the messages logged from the IParameterInspector implementation to reflect a call site of "Example.MyService.GetContacts" where Example.MyService is your service (as indicated by the instanceType parameter) and "GetContacts" is the operation. You could synthesize the call site information manually. You would still use NLog's Logger.Log method and you would still create a LogEventInfo object. Additionally, you can store the "class" and "method" in the LogEventInfo.Properties object. Rather than retrieving a logger (from LogManager) based on the instanceType (i.e. the service), retrieve the logger based on the type of the parameter inspector (NLogLogger in your case). Finally, you can add an additional rule to your NLog.config (and apply it to the NLogLogger type) so that rule has a different logging format. You will manually add a field to the logging format that contains the call site information (that you stored in the LogEventInfo.Properties collection) in the same position as the "real" callsite LayoutRenderer in your other logging rule configurations. 
 
Next I will post a new version of your NLogLogger implementation that does what I described above.
 
public class NLogLogger : IParameterInspector
{
    private static readonly NLog.Logger logger = LogManager.GetCurrentClassLogger();

    private void Log(Type instanceType, string operationName, string msg)
    {
        NLog.Logger serviceLogger = LogManager.GetLogger(
            instanceType.FullName, instanceType);

        //Create LogEventInfo with the Logger.Name from the logger associated with the service
        LogEventInfo le = new LogEventInfo(LogLevel.Info, serviceLogger.Name, msg);
        le.Properties.Add("fakecallsite", string.Format("{0}.{1}",instanceType.ToString(),operationName);

        //Log the message using the parameter inspector's logger.
        logger.Log(typeof(NLogLogger), le);
    }

    public object BeforeCall(string operationName, object[] inputs)
    {
        // Retrieve the service instance type for the logger then log the call.
        OperationContext operationContext = OperationContext.Current;
        Type instanceType = operationContext.InstanceContext
            .GetServiceInstance().GetType();
        Log(instanceType, operationName, "BeforeCall");

        return instanceType;
    }

    public void AfterCall(
        string operationName, object[] outputs,
        object returnValue, object correlationState
    )
    {
        if (correlationState is Type)
            Log(correlationState, operationName, "AfterCall");
    }
}
 
Your NLog.config will have rules something like this. One rule is specifically for your NLogLogger Parameter Inspector. It logs to "f1" and is a "final" rule, meaning that logging messages from the parameter inspector won't be logged by any other rules. The other rule is for all other loggers. Each logs to a different file target, but both file targets write to the same file (which works, I think). The key is that each file has its own layout.
 
<logger name="Your.Full.NameSpace.NLogLogger" minlevel="*" writeTo="f1" final="true" /> 
<logger name="*" minlevel="*" writeTo="f2" /> 
 
Your targets and layouts would look something like this. We are defining a variable whose value is the value of the EventPropertiesLayoutRenderer, which is the fake call site that we stored in LogEventInfo.Properties["fakecallsite"].
 
  <variable name="fakecallsite" value="${event-properties:fakecallsite}"/>
  <variable name="f1layout" value="${longdate} | ${level} | ${logger} | ${fakecallsite} | ${message}"/>
  <variable name="f2layout" value="${longdate} | ${level} | ${logger} | ${callsite} | ${message}"/>
  <targets>
    <target name="f1" xsi:type="File" layout="${f1layout}" fileName="${basedir}/${shortdate}.log" />
    <target name="f2" xsi:type="File" layout="${f2layout}" fileName="${basedir}/${shortdate}.log"        />
  </targets>
 
Note that I have not tried this, but I think it should work (or should be close enough that you can get it working). One limitation is that, since we are calculating the fake call site, we cannot use the real callsite LayoutRenderer to manipulate the contents of the fakecallsite field in the output. If this important, it can probably be simulated by storing the class and method separately (in LogEventInfo.Properties) and then setting the "fakecallsite" variable in the NLog.config to contain the class, the method, or both.
 
END UPDATE
 
Your wrapper should use the Log method. Also, the type you pass to the NLog Logger.Log method should be the type of your NLog Logger wrapper, not the type of the type of the service instance. You can still use the type of your service instance to retrieve the right Logger instance. It should look something like this:
 
public class NLogLogger : IParameterInspector
{
    private void Log(Type instanceType, string operationName, string msg)
    {
        NLog.Logger logger = LogManager.GetLogger(
            instanceType.FullName, instanceType);

        //This is the key to preserving the call site in a wrapper.  Create a LogEventInfo
        //then use NLog's Logger.Log method to log the message, passing the type of your 
        //wrapper as the first argument.

        LogEventInfo le = new LogEventInfo(LogLevel.Info, logger.Name, msg);
        logger.Log(typeof(NLogLogger), le);
    }

    public object BeforeCall(string operationName, object[] inputs)
    {
        // Retrieve the service instance type for the logger then log the call.
        OperationContext operationContext = OperationContext.Current;
        Type instanceType = operationContext.InstanceContext
            .GetServiceInstance().GetType();
        Log(instanceType, operationName, "BeforeCall");

        return instanceType;
    }

    public void AfterCall(
        string operationName, object[] outputs,
        object returnValue, object correlationState
    )
    {
        if (correlationState is Type)
            Log(correlationState, operationName, "AfterCall");
    }
}