To pick up this aging thread ... I was wondering why the built-in Trace classes aren't used in Nant for this? I recently finished a project where we implemented logging in our application using Trace.Writeline (etc.) with a set of custom TraceListeners. Trace.WriteLine accepts an object in one of the overloads, so we created a custom TraceMessage class that stored extra information about the message being written (so individual Listener types could filter messages, for example). Our custom TraceListeners inherit from a base class (that in turn inherits from TraceListener, of course) that knows how to deal with TraceMessages, and creates TraceMessages if the string overloads were used instead.
Is there a reason that sort of system wouldn't work in Nant, rather than creating something entirely from scratch? Advantages also include the ability then to add listeners via the .config file, and a Listener model that future developers may already be familiar with. Thanks, Scott Boston -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of [EMAIL PROTECTED] Sent: Monday, July 22, 2002 5:26 PM To: [EMAIL PROTECTED] Cc: 'Nant-Developers (E-mail)'; [EMAIL PROTECTED] Subject: Re: [nant-dev] Logging and Events Hi Scott, Sorry that this got a little long, but as you will see I have been thinking about this a lot lately :-) I have been chewing on this since last week when I asked about what it would take to get an xml log. After trading emails with the list, I took a look at Ant for inspiration and found that Ant 1.5 has an event system very similar to what you've described, except that they include another event for messages. The code that Gerry posted seems to point that way as well -- but I haven't dug into yet. As I mentioned recently, we are working on a port/rewrite of CruiseControl for the .NET platform. While implementing a class to drive NAnt, we realized that we couldn't get an XML report of the results back to merge with the rest of our workflow execution report. So I had been considering implementing something similar to what you describe in order to get us past our roadblock, and hopefully help NAnt mature its logging. Here are my thoughts so far: I agree with both of these statements: Events and logs serve a different purpose. Something like Log4Net would be very nice instead of writing one. The way I see it though, these two items are not completely unrelated. For example, if one were to want to produce an XML result of an execution, it would be very effective to create the log by using events at the beginning and end of each target/task to create elements for each of them in the resultant XML. In order to facilitate this sort of log building an XML logger would need be no more than just another event handler. Implementing this or other types of logging classes using Log4Net would then be an implementation detail of an event handling class, and not known throughout NAnt's code. Another advantage of this is that if someone wanted a simpler logger (or to use some other logging tool) they could simply implement the Logger interface, and they'd be off and running (In Ant 1.5 Loggers appear to be an extension of listeners, but I haven't looked at it in detail). What NAnt has now is explicit logging, possibly to multiple loggers but with no way for the loggers to know the context of what is being logged. What we seem to want to go is toward explicit event notification with Logging being a valid listener and the ability to easily specify additional/different listeners. This isn't too huge of a difference from where NAnt is now. The problem I see, is getting from here to there. There are a couple of things that make this a non-trivial exercise: 1)Currently the Logger is explicitly mentioned in every target and task. 2)The formatting of the message for the console is expressed at each Log invocation. 3)There is no non-programmatic way of specifying additional Logger/Listeners 4)Messages being raised as events would require large changes And a couple of things in our favor: 1)Logger is already abstracted 2)The code is already structured for multiple LoggerListeners So, as I scoped this out last week, I came up with the following tasks for preparing the code to support an XML event handler/Logger: 1) factor all log statements that use LogPrefix, pushing this behavior down to the specific LoggerListener (in this case ConsoleLogger) This can be done by adding an Element parameter in an overload to the Write and WriteLine methods in Log and LoggerListener. 2) Implement events at build start, build end, target start, target end by changing Project.Execute, Target.Execute and Task.Execute 3) Modify LoggerListeners to implement EventHandling methods 4) add a command line argument for specifying additional listeners (e.g. -listener xml) 5) modify Log class to allow adding listeners to the _listeners collection 6) register event handlers for each listener for each event 7) in ListenerLogger event handlers emit appropriate text on event. 8) remove log calls for targets (it will be provided via handler) and in ConsoleLogger implement onTargetStart to emit TargetName: I actually implemented step one for a few tasks, and verified that it works. Once completing all 8 steps, the code would work as it does now, but adding XML Logging would be a simple matter of adding an XML LoggerListener and a line to the command line args to support it. >From there it would be a matter of removing all the calls to Log and replacing them with a message event to complete the migration to event-based notifications. Once that is complete it should be easy to add a Log4NetListener that used Log4Net to accomplish logging. -- Or at least it would be like that according to what i have learned so far, those next 7 steps might change my mind a bit. I was tentatively planning on doing the rest of that refactoring starting tomorrow (because we need to demo CruiseControl in a couple of weeks). My very next step was to look at Gerry's code in more detail, and then start on steps 2 & 3 above. Best, Bill "Scott Hernandez" <[EMAIL PROTECTED]> To: "'Nant-Developers \(E-mail\)'" <[EMAIL PROTECTED]> Sent by: cc: [EMAIL PROTECTED] Subject: [nant-dev] Logging and Events ceforge.net 07/22/2002 02:46 PM I've been giving some thought to logging and an event system for nant. I don't think these two systems should be the same. They serve two different purposes and don't need to overlap. In my mind logging should be done via a mature logger, and it would be great if we didn't have to write it. I'd like to suggest that we use Log4Net. As for events, it seems like the following are probably going to be important: Build Start/End Target Start/End Task Start/End It would also be nice for the event system to allow for interception and cancel-ability. Thoughts? ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ Nant-developers mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/nant-developers ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ Nant-developers mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/nant-developers
