I am wondering about what the difference between logging and tracing is.

Is the difference basically that tracing is more detailed log giving developers a tool to debug applications at runtime?

I have been experimenting with log4net and doing logging. Now I am wondering if I should be doing tracing as well and if I could/should use log4net for that purpose. 
Should I be doing tracing with log4net and is there some trace level for log4net loggers? Should I use a different log level for debug and trace purposes or is it ok to use the same?
Can you give a simple example on how I would do logging and tracing for a simple method?

Edit:
Despite a few helpful answers below I am still unsure how I should be doing tracing versus logging. 

I have the following method in my Business layer and I want to add logging/tracing to it. I am wondering how to do it efficiently. Is the following method acceptable in terms of logging/tracing? Should the log messages be of type Info instead of Debug? Are the Debug messages I am logging considered trace? How would you change it?

&lt;pre&gt;
&lt;code&gt;
IEnumerable&amp;lt;Car&amp;gt; GetCars()
{
   try
   {
      logger.Debug(&quot;Getting cars&quot;);
      IEnumerable&amp;lt;Car&amp;gt; cars = CarAccessor.GetCars().ConvertAll(DataAccessToBusinessConverter);
      logger.Debug(&quot;Got total of &quot; + cars.Count + &quot; cars&quot;); 
   } catch (Exception e) {
      logger.Error(&quot;Error when getting cars&quot;, e);
      throw new Exception(&quot;Unexpected error when getting cars&quot;);
   }
}
&lt;/code&gt;
&lt;/pre&gt;

Tracing versus Logging and how does log4net fit in?

My Python library just changed it&#39;s main module name from `foo.bar` to `foobar`. For backward compat, `foo.bar` still exists, but importing it raises a few warnings. Now, it seems some example program still imports from the old module, but not directly.

I&#39;d like to find the erroneous `import` statement. Is there any tool that allows me to trace imports and find the culprit without wading through all of the code?

Trace Python imports

In a shell script, how do I echo all shell commands called and expand any variable names?

For example, given the following line:

    ls $DIRNAME

I would like the script to run the command and display the following

    ls /full/path/to/some/dir

The purpose is to save a log of all shell commands called and their arguments. Is there perhaps a better way of generating such a log?



How to echo shell commands as they are executed

How can I have some debug information regarding git/git-shell? 

I had a problem, that `user1` could clone a repository without problem, while `user2` could clone only an empty one. I had set `GIT_TRACE=1`, but nothing useful was told.

Finally, after a long trial and error, it turned out that it was a permission problem on a file. An appropriate error message could short-circuit this problem.

How can I debug git/git-shell related problems?

I want to introduce some tracing to a C# application I am writing. Sadly, I can never really remember how it works and would like a tutorial with reference qualities to check up on every now and then. It should include:

  - App.config / Web.config stuff to add for registering TraceListeners
  - how to set it up in the calling application

Do you know the &#252;ber tutorial that we should link to?

&lt;hr/&gt;

Glenn Slaven pointed me in the right direction. Add this to your App.config/Web.config inside `&lt;configuration/&gt;`:

    &lt;system.diagnostics&gt;
        &lt;trace autoflush=&quot;true&quot;&gt;
          &lt;listeners&gt;
            &lt;add type=&quot;System.Diagnostics.TextWriterTraceListener&quot; name=&quot;TextWriter&quot;
                 initializeData=&quot;trace.log&quot; /&gt;
          &lt;/listeners&gt;
        &lt;/trace&gt;
    &lt;/system.diagnostics&gt;

This will add a `TextWriterTraceListener` that will catch everything you send to with `Trace.WriteLine`, etc.

@DanEsparza pointed out that you should use `Trace.TraceInformation`, `Trace.TraceWarning` and `Trace.TraceError` instead of `Trace.WriteLine`, as they allow you to format messages the same way as `string.Format`.

**Tip:** If you don&#39;t add any listeners, then you can still see the trace output with the Sysinternals program [DebugView][1] (`Dbgview.exe`): 

  [1]: https://docs.microsoft.com/en-us/sysinternals/downloads/debugview





How can I add (simple) tracing in C#?

So I&#39;m trying to do something simple, I want to break up my traces in the console into several lines, using 1 console.log statement:

    console.log(&#39;roleName = &#39;+roleName+&#39; role_ID = &#39;+role_ID+&#39; modal_ID = &#39;+modal_ID+\n+&#39;related = &#39;+related);

How would you write the above to trace out the following?

    roleName = test
    role_ID = test
    modal_UD = test
    related = test

instead of `roleName = test role_ID = test modal_UD = test related = test`


I&#39;ve checked out several other questions which appear similar, but none have helped or are talking about a different thing.

Thanks for taking a look!

When tracing out variables in the console, How to create a new line?

Let&#39;s say I&#39;m working on a little batch-processing console app in VB.Net.  I want to be able to structure the app like this:

&lt;!-- language-all: lang-vb --&gt;

    Sub WorkerMethod()
       &#39;Do some work
       Trace.WriteLine(&quot;Work progress&quot;)

       &#39;Do more work
       Trace.WriteLine(&quot;Another progress update&quot;)

       &#39;...
    End Sub


    Sub Main()
       
       &#39;Do any setup, like confirm the user wants to continue or whatever
        
       WorkerMethod()     

    End Sub

Note that I&#39;m using `Trace` rather than `Console` for my output.  This is because the worker method may be called from elsewhere, or even live in a different assembly, and I want to be able to attach different trace listeners to it.  So how can I connect the console to the trace? 

I can already do it by defining a simple class (shown below) and adding an instance to the Trace&#39;s listeners collection, but I&#39;m wondering if there&#39;s a more accepted or built in way to accomplish this:

    Public Class ConsoleTrace
        Inherits Diagnostics.TraceListener

        Public Overloads Overrides Sub Write(ByVal message As String)
            Console.Write(message)
        End Sub

        Public Overloads Overrides Sub WriteLine(ByVal message As String)
            Console.WriteLine(message)
        End Sub
    End Class



Redirect Trace output to Console

In [this thread][1] many people have indicated that they use log4net. I am a fan of TraceSources and would like to know why log4net is used. 

Here is why I like trace sources:

 - Pluggable listeners - XML, TextFile, Console, EventLog, roll your own
 - Customisable trace switches (error, warning, info, verbose, start, end, custom)
 - Customisable configuration 
 - The Logging Application Block is just a big set of TraceListeners
 - Correlation of activities/scopes (e.g., associate all logs within an ASP.NET request with a given customer
 - The Service Trace Viewer allows you to visualize events against these activities individually
 - All of it is configurable in app.config/web.config.

Since the .NET framework internally uses TraceSources, it also gives me a consistent way of configuring tracing - with log4net, I have to configure log4net as well as TraceSources. 

What does log4net give me that TraceSources don&#39;t (or that couldn&#39;t be done by writing a couple of custom TraceListeners)?


  [1]: https://stackoverflow.com/questions/576185/logging-best-practices

log4net versus TraceSource

I am trying to start using `erlang:trace/3` and the `dbg` module to trace the behaviour of a live production system without taking the server down.

The [documentation][1] is [opaque][2] (to put it mildly) and there don&#39;t appear to be any useful tutorials online.

What I spent all day trying to do was capture what was happening in a particular function by trying to apply a trace to `Module:Function` using `dbg:c` and `dbg:p` but with no success at all.

Does anyone have a succinct explanation of how to use trace in a live Erlang system?


  [1]: http://erldocs.com/R13B03/erts/erlang.html?search=erlang:trace&amp;i=0#trace/3
  [2]: http://erldocs.com/R13B03/erts/erlang.html?search=erlang:trace&amp;i=0#trace/3

How to use trace and dbg in Erlang to debug and trace my program?

I have implemented a custom trace listener (derived from `TextWriteTraceListener`) and now I would like to set my application to use it instead of standard `TextWriteTraceListener`.

First I added default `TextWriteTraceListener` in order to make sure it works ok and it does. Here&#39;s my app.config:

    &lt;configuration&gt;
        &lt;system.diagnostics&gt;
            &lt;trace autoflush=&quot;true&quot; indentsize=&quot;4&quot;&gt;
                &lt;listeners&gt;
                    &lt;add name=&quot;TextListener&quot;  type=&quot;System.Diagnostics.TextWriterTraceListener&quot; initializeData=&quot;trace.log&quot; /&gt;
                &lt;remove name=&quot;Default&quot; /&gt;
                &lt;/listeners&gt;
            &lt;/trace&gt;
        &lt;/system.diagnostics&gt;
    &lt;/configuration&gt;

Now my trace listener is defined in `MyApp.Utils` namespace and it&#39;s called `FormattedTextWriterTraceListener`. So I changed the type in the config above to `MyApp.Utils.FormattedTextWriterTraceListener` and it currently looks like that:

    &lt;configuration&gt;
        &lt;system.diagnostics&gt;
            &lt;trace autoflush=&quot;true&quot; indentsize=&quot;4&quot;&gt;
                &lt;listeners&gt;
                    &lt;add name=&quot;MyTextListener&quot; type=&quot;MyApp.Utils.FormattedTextWriterTraceListener&quot; initializeData=&quot;trace.log&quot; /&gt;
                &lt;remove name=&quot;Default&quot; /&gt;
                &lt;/listeners&gt;
            &lt;/trace&gt;
        &lt;/system.diagnostics&gt;
    &lt;/configuration&gt;

However now when I try to log something I&#39;m getting a `ConfigurationErrorsException` with the message:

&gt;Couldn&#39;t find type for class MyApp.Utils.FormattedTextWriterTraceListener.

Does anyone knows how can I set up this custom listener in config and if it&#39;s even possible?

How to define custom TraceListener in app.config

I am looking for a tool like [ltrace][1] or [strace][2] that can trace locally defined functions in an executable.  ltrace only traces dynamic library calls and strace only traces system calls.  For example, given the following C program:

    #include &lt;stdio.h&gt;
    
    int triple ( int x )
    {
      return 3 * x;
    }
    
    int main (void)
    {
      printf(&quot;%d\n&quot;, triple(10));
      return 0;
    }

Running the program with `ltrace` will show the call to `printf` since that is a standard library function (which is a dynamic library on my system) and `strace` will show all the system calls from the startup code, the system calls used to implement printf, and the shutdown code, but I want something that will show me that the function `triple` was called.  Assuming that the local functions have not been inlined by an optimizing compiler and that the binary has not been stripped (symbols removed), is there a tool that can do this?

**Edit**

A couple of clarifications:

  - It is okay if the tool also provides trace information for non-local functions.
  - I don&#39;t want to have to recompile the program(s) with support for specific tools, the symbol information in the executable should be enough.
  - I would be really nice if I could use the tool to attach to existing processes like I can with ltrace/strace.

  [1]: http://linux.die.net/man/1/ltrace
  [2]: http://linux.die.net/man/1/strace

Tool to trace local function calls in Linux

coming from the Ocaml community, I&#39;m trying to learn a bit of Haskell. The transition goes quite well but I&#39;m a bit confused with debugging. I used to put (lots of) &quot;printf&quot; in my ocaml code, to inspect some intermediate values, or as flag to see where the computation exactly failed.

Since printf is an **IO** action, do I have to lift all my haskell code inside the **IO** monad to be able to this kind of debugging ? Or is there a better way to do this (I really don&#39;t want to do it by hand if it can be avoided)

I also find the **trace** function : 
http://www.haskell.org/haskellwiki/Debugging#Printf_and_friends
which seems exactly what I want, but I don&#39;t understand it&#39;s type: there is no **IO** anywhere!
Can someone explain me the behaviour of the trace function ?

How to &quot;debug&quot; Haskell with printfs?

I&#39;d like to get stories on how people are handling tracing and logging in real applications. Here are some questions that might help to explain your answer. 

**Frameworks**

What frameworks do you use?

 - log4net
 - System.Diagnostics.Trace
 - System.Diagnostics.TraceSource
 - Logging application block
 - Other?

If you use tracing, do you make use of Trace.Correlation.StartLogicalOperation? 

Do you write this code manually, or do you use some form of aspect oriented programming to do it? Care to share a code snippet? 

Do you provide any form of granularity over trace sources? E.g., WPF TraceSources allow you to configure them at various levels:

 - System.Windows - *settings for all of WPF*
 - System.Windows.Animation - *override specifically for Animation.*

**Listeners**

What log outputs do you use?

 - Text files
 - XML files
 - Event log
 - Other?

If using files, do you use rolling logs or just a single file? How do you make the logs available for people to consume? 

**Viewing**

What tools to you use for viewing the logs?

 - Notepad
 - Tail
 - Event viewer
 - Systems Center Operations Manager/Microsoft Operations Manger
 - WCF Service Trace Viewer
 - Other?

If you are building an ASP.NET solution, do you also use ASP.NET Health Monitoring? Do you include trace output in the health monitor events? What about Trace.axd? 

What about custom performance counters? 

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