How do I use NLog ILogger.Error(Exception, String,Object[]) - nlog

NLog has a method ILogger.Error(Exception, String,Object[]) See Ref.
What kind of layout renderer can I use to log the args Object[]?
Alternatively, is there any other way to log all local variables?

The args Object[] will be included in the message as format string arguments.
So NLog calls string.Format(message, args) where messages is your log message and args are the "fillers" in that message.
Then this formatted message can be accessed with the ${message} layout render to include in your logs.
I'm not aware of any automatic logging of local variables so you need to pass them manually to the Error method using the args parameter.

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MapUtils with Logger

I am using MapUtils.verbosePrint(System.out, "", map) to dump the contents of a map in Java. They (management) do not like us using System.out.println().
We are using log4j. They made the logger into a variable "l" so we can say something like l.debug("This is going to the logfile in debug mode).
I would like to get the output buffer(s) from l so I could pass it into verbosePrint() instead of System.out. I looked at all the methods and members of the logger and did things like getAppenders() and tried all those elements but I could not find anything that helped.
Has anyone else done this? I know the logger may write to > 1 output.
You can use Log4j IOStreams to create PrintStreams that will send everything to a logger. This is mostly useful to log debug output from legacy APIs like JDBC or Java Mail that do not have a proper logging system. I wouldn't advise it in other cases, since your messages might be merged or split into several log messages.
I would rather use one of these approaches:
simply log the map using Logger#debug(Object). This will lazily create an ObjectMessage (only if debug is enabled), which is usually formatted using the map's toString() method. Some layouts might format it differently (like the JSON Template Layout).
eagerly create a MapMessage or StringMapMessage:
if (l.isDebugEnabled()) {
l.debug(new MapMessage(map));
}
This gives you more formatting options. For example the layout pattern %m{JSON} will format your message as JSON.
if your are set on the format provided by MapUtils#verbosePrint, you can extend ObjectMessage and overwrite its getFormattedMessage() and formatTo() methods.
public String getFormattedMessage() {
final ByteArrayOutputStream os = new ByteArrayOutputStream();
MapUtils.verbosePrint(new PrintStream(os), "", );
return new String(os.toByteArray());
}

How to enable logging debug messages when root logger is INFO?

I use logger org.apache.commons.logging.Log.
File log4j.properties is:
log4j.rootCategory=INFO, S
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.logger.org.springsource.sawt=DEBUG
log4j.logger.org.w3c.tidy=INFO
...................
When I use debug method of org.apache.commons.logging.Log it doesn't log anything.
How to change log4j.properties to enable logger log debug messages?
It is really simple.
If you want to log all debug,info,warn.error,fatal messages from logger you need to take name of logger provided at instantiation by method LogFactory.getLog(loggerName) and append it to log4j.logger`. Thus you get
log4j.logger.loggerName=DEBUG
But it's common that loggerName is String from getClass() method. Thus you can use package name to set logger's level for that package.

switching FileAppenders on the fly

I've got a legacy logging class. Its got a static Logger reference (named logger) and a bunch of static methods.
Each method takes a String input and writes it to System.out.println and to logger if logger is not null.
Its got a constructor that initializes logger. But this constructor only has package scope and I'm pretty sure its not being called anywhere. Therefore logger is always null and the class essentially only ever executes System.out.println
I want to change this so it can be used in a multi threaded application where each thread writes to its own unique FileAppender.
And that's where I'm stuck.
Basically, what I want to do is have this static class associated with a bunch of different log4j FileAppenders. Each FileAppender can be created by the Thread, and the file name can be derived from unique information known to the Thread.
What I can't figure out how to do is magically use Log4j to communicate that Thread's unique FileAppender to this legacy logging class.
Ideas? Hints? Suggestions?
Mark
It is possible to change the target log file name dynamically using a RoutingAppender and the ThreadContext map.
This can all be done with configuration (no need for custom code where threads create FileAppenders). In the RoutingAppender configuration you can specify a ThreadContext key you want to use to switch the target FileAppender. For example, you can use the string "ROUTINGKEY". Each thread puts a unique value in the ThreadContext map for key "ROUTINGKEY", and this value is used to select the Appender that the log event is routed to. You can even set it up to dynamically create log files that have the ROUTINGKEY value in the file name, so not all target log files need to be known in advance.
The FAQ page has a good example: http://logging.apache.org/log4j/2.x/faq.html#separate_log_files

documentation on how to use MSBuild Namespace in C# Source code

I am looking for some simple answers on how to use funktionality from MSBuild in a c# program. The native documentation seems to be completely useless, because I only find information like:
ConsoleLogger.ApplyParameter
Applies a parameter to the logger
This is the prototype of a explanation, that had better never been written. Neither here, nor under the parameters type explanation you find e.g. a link or any examples about what the parameters might be there for, or their names, or where to find that information
The tutorials I find are all about MSBuild as a standalone tool.
At the moment I need to understand, how to get more information about a failed build:
This method just returns true or false.
bool success = project.Build(new string[] { "Build", "Deploy"}, fileLogger);
Also I need understand how to configure the filelogger, and how to use it from project.
Microsoft.Build.Logging.FileLogger fileLogger = new Microsoft.Build.Logging.FileLogger();
For the particular example in your question, ApplyParameter works the same way that the console logger parameters (/clp) work from the command line.
> msbuild /?
...
/consoleloggerparameters:<parameters>
Parameters to console logger. (Short form: /clp)
The available parameters are:
PerformanceSummary--Show time spent in tasks, targets
and projects.
Summary--Show error and warning summary at the end.
NoSummary--Don't show error and warning summary at the
end.
ErrorsOnly--Show only errors.
WarningsOnly--Show only warnings.
NoItemAndPropertyList--Don't show list of items and
properties at the start of each project build.
ShowCommandLine--Show TaskCommandLineEvent messages
ShowTimestamp--Display the Timestamp as a prefix to any
message.
ShowEventId--Show eventId for started events, finished
events, and messages
ForceNoAlign--Does not align the text to the size of
the console buffer
DisableConsoleColor--Use the default console colors
for all logging messages.
DisableMPLogging-- Disable the multiprocessor
logging style of output when running in
non-multiprocessor mode.
EnableMPLogging--Enable the multiprocessor logging
style even when running in non-multiprocessor
mode. This logging style is on by default.
Verbosity--overrides the /verbosity setting for this
logger.
Example:
/consoleloggerparameters:PerformanceSummary;NoSummary;
Verbosity=minimal
So for the example shown in the help,
logger.ApplyParameter("PerformanceSummary", "NoSummary");
logger.ApplyParameter("Verbosity", "minimal");
If you need a high degree of control over a logger you are attaching to the build engine from code, you might want to consider writing your own logger rather than trying to interpret/parse the text output from the stock console logger.

How to get log4net to output to the same place as TestContext.WriteLine

How can I setup log4net to write to the Output window of MsTest?
The only function I've been able to output to that window with is TestContext.WriteLine, but I do not know if there is an appender that can do that. Trace and Console outputs do not work.
I created a custom appender that I could pass the TestContext to, and use the WriteLine method on that for logging.
To setup log4net to use the TestContext, I created a custom appender (NUnitLogAppender.cs):
https://gist.github.com/dropthemic/f360c389c35758bbb94e67b3aee09157
This is based off Console appender. To write to TestContext or TestContext.Progress, set the "Target" in NUnitLogAppender class.

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