Configuring a Log4Net logger using AppSettings - c#

I'm currently switching the logging system of a project away from a homemade logger to Log4Net. Under the previous logger we had created, AppSettings.config contained keys to control whether the app logged to the console, a file, or both. Now, using Log4Net, we will be logging to console, file, and database. Also, I have the configuration for Log4Net set up in an external config, so the files concerned are App.config, Log4Net.config, and AppSettings.config.
My question: Will it be possible to continue using keys from AppSettings to control the combination of these three methods used? I know I can create a set of loggers covering the different combinations, but controlling it directly through AppSettings seems far more efficient, and would be my preferred method of doing things.
Thank you very much for your help and expertise.

You can in your Log4Net.config configure how you want to get the output.
It is possible to get to logging to all three types.

There is not a way to configure log4net to use your AppSettings.config out of the box, but you can write your own Configurator and manually add appenders to your Loggers at runtime as outlined here. It is still some extra overhead to avoid what log4net gives you anyway. What is the benefit of using AppSettings.config as you see it?

Related

Log4Net multiple configurations in single config file

Is there any possibility to create single log4net.config file containing multiple configurations. I would like to create different logs depending on some kind of parameter that will choose proper configuration with appenders from logger config file.
e.g. I have two different projects, in each of them I need to create different logs. By reading the same for both projects config file in assembly.info and giving some kind of parameter i could choose different logger configurations to be used in projects.
I would be grateful for any help with it.
Basically everything you can do is mentioned here:
https://logging.apache.org/log4net/release/manual/configuration.html
and examples are here:
https://logging.apache.org/log4net/release/config-examples.html
Now, initializing your Logger you can choose the config file to be used. If you want it to be all in the app config file, then you simply provide ONE configuration.
However, if you need to have different behavior for different cases (projects/classes), just specify filters that will decide which appender should be used in a moment.
Filter can base on the class name, ex. check here as it was already discussed:
log4net: Configure to ignore messages from a specific class

Multiple Webservices with shared web.config logging to separate flat files with Ent Lib

I'm working on a project where I'm required to use Enterprise Library v.3.1.1.0 Logging block (wish it was log4net or nlog, but I don't get a choice). We have an IIS application where several WCF webservices are hosted, and they share a single web.config file. This is also something I'm not at liberty to change.
None of these services had any logging implemented previously.
So it's pretty straight forward to use the Ent Lib Config utility to set up a rolling flat file listener, and log to a text file the way I want. The problem I'm having is configuring it properly though so each service can have their own separate log file, while they still all share the same web.config.
I've gone through several tutorials, but I'm not understanding how to do this.
Any tips?
The configuration in the web.config is static so there will be one file per configured trace listener. One approach to achieve one file per service is to have each service log to a different category and each category uses a different trace listener. This could even be done programmatically so that services can add their own trace listener's at runtime although this is a bit more advanced than updating the configuration file manually (e.g. ensure service is added only once as well as ensuring that when the configuration is updated it is thread-safe).
Enterprise Library does not have anything analogous to log4net's hierarchical loggers so there is no out of the box way to use reflection to route log messages based on the originating class. It might be possible but you will have to write some code. You could write a Logger facade class to set the category based on the callers namespace. (Also note that there is no namespace wildcard matching like log4net.)

log4Net dilemma

I have a C# solution containing multiple C# projects. I am planning to add logging in it. This logging should be available in all the projects and preferably use log4Net with rolling file logs.
With the above said premise, I could think of two ways to do that.
Initialize logger in entry point (Program class) of the solution & Get the logger instance & use it as a member variable for every class that needs logging.
Add another project, Utilities & define a Logging class with static logging methods. This class should be initialized in entry point (Program class) of the solution.
What could be the best possible solution?
I have a similar situation. What we've done is use 1 app config for all the projects and use links to reference it.
In the app.config for your app you set the log4net config Section
<configSections>
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
</configSections>
And later set the Appender:
<log4net>
<appender name="RollingLogFileAppender" type="log4net.Appender.RollingFileAppender">
...
And in each class you want to log you put a line similar to this:
private static readonly ILog log = log4net.LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
Then each class grabs the same logger (singleton).
Would that work for you?
In my projects, I wrote a wrapper around LOG4NET to (theoretically) exchange it with other logging frameworks like NLOG without breaking my code.
My own logging class is accessible through a static singleton. It does initialization in this singleton.
(BTW: I published the source code over at the Code Project some time ago, maybe it gives you some inspiration)
If you're thinking about initializing something at the entry point every single time, then you're writing yourself a case for dependency injection. Using a DI library (like Unity, Castle, or whatever flavor you personally like), you could do either constructor injection or property injection to get your logger class (or Log4Net) initialized automatically.
Additionally, you can use the DI kernel to make it a singleton, so that you only have one instance of it active.
Building off of Queso's answer, we had .dll's that were imported with reflection at runtime. In order to get them to use Log4Net we created a log4net.config file with all the appropriate config sections. We also used the same line of code to intialize the log in each class that Queso references. The seperate config allowed us to use it throughout the entire app domain.
EDIT we also had to make a modifcation to the appsettings file to allow for this.
http://haacked.com/archive/2005/03/07/ConfiguringLog4NetForWebApplications.aspx
Option 1 is the way to go.
If you use static methods you loose the ability to use hierarchical loggers. This feature allows you to configure your log output differently for individual classes or even for entire sub systems e.g. YourNameSpace.Security. This tutorial elaborates on this topic (also the other chapters are a good read).
Building a wrapper is certainly not a bad idea, but it is not strictly necessary. It does allow for a few things though: change log framework, use DI, add additional log levels (e.g. log.Verbose()) or different overloads for logging...
Btw. I would initialize the loggers like this:
ILog log = LogManager.GetLogger(typeof(YourClass));

c# pattern for two applications sharing a configuration file

I have two applications that have many common configuration properties. When a configuration property of one changes, I want the other to change as well. Does anyone have a sensible way to accomplish this before I start off down the wrong track?
EDIT: I'm using .NET 2.0
You can create and reference a common configSource for the configuration section(s) involved. For instance, if you wanted a common set of AppSettings, copy your current appSettings to a new file (say appSettings.shared.config) and replace them in both app configs with this:
<appSettings configSource="appSettings.shared.config"/>
Here's more documentation: http://sunali.com/2008/01/23/configsource-property-dividing-configuration-files-into-pieces/
Far as I know, this cannot be done for an entire file, only sections, and each section will need its own file (and the section must still be declared in the configurationsections element of the app.config). But, this has a number of really cool uses; for instance, you can separate your connection strings into files geared towards different environments (local, development, testing, staging, production) and by changing one filename in one place you've now pointed your app at the different environment.
One easy way to accomplish this is to use the configSource attribute in the app.config in both applications, and point this to a common file. Bingo, change one file, all apps are updated.
Check the MSDN documentation on it here.
there are a couple of different ways you could do this:
use the registry
use a config file in a common location
use a configuration table in a database

Configuring log4net in a VSTO

I've set up my VSTO Excel add-in to use log4net for logging. Unfortunately I'm (seemingly) not able to make it configure itself from the app.config (which I deliver together with the add-in via ClickOnce).
I have read http://www.darinhiggins.com/?p=13 which lists some ways to get the file name of the app.config and then configure log4net with
log4net.Config.XmlConfigurator.Configure(fileInfo)
However the approaches this blog lists seem very error-prone to me (they "smell bad").
Things like
ConfigurationManager.GetSection
make me believe the .NET framework knows exactly where to get the file and there must be a way to retrieve this information from the framework instead of having to figure it out on my own. However, the XmlConfigurator in turn only accepts a file name, stream or xml node...
(Why I believe it's not working at the moment: I have configured it to use a RollingFileAppender with the file name being H:\Data\Debug.log, but after a GetLogger(...).Debug(...), there is still no Debug.log in place...). I have used the exact same configuration in other places, successfully.
XmlConfigurator.Configure(); uses the app.config file. That should work since the ConfigurationManager seems to be able to read the config file.

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