Develop Reference

Is there a way to dynamically change log name at runtime?

I currently am writing to a statically named log file as defined in my serilog config:
<add key="serilog:write-to:File.path" value="%LOCALAPPDATA%\App_Data\Logs\StaticallyNamedLog.log" />
I'd like to be able to change the logfile name at runtime i.e.
<add key="serilog:write-to:File.path" value="%LOCALAPPDATA%\App_Data\Logs\{appname}-Log.log" />
In log4net for example I'd set a log4net global property value for "appname" in code before the settings were read in.
log4net.globalContext.properties["appname"] = "App1"
log4net.config.xmlConfigurator.configure("log4net.config")
Then in the logfile I'd reference it like so
%property{appname}
This would then get substituted into this path.
How can I do the equivalent in Serilog? I've done a lot of searching but can't find anything on this specific problem.
Thanks

Check NLog minlevel before logging?

I want to enable developers to log objects as JSON with NLog. To do this I need to implement some logic before sending to nLog OR before sending to target.
I can build my own Target(TargetWithLayout) but I can´t find a way to check the log level from the config for this specific target/logger? Another drawback is that I need to make a new TargetWithLayout class for each target that we will use (EventLog, File, WebService and so on).
Another solution would be to do it in my LogHandler that uses NLog. The only way to know if I should translate the object is probably to read all the loggers from the config file, if any of them is set to log objects then I serialize. I am however not sure if I can check this information from the LogHandler (without doing it manually)?

You can use the NLog-Logger object to query active logging-rules:
if (myLogger.IsTraceEnabled)
myLogger.Trace("Hello World");

You can use the NLog json layout to write json in you log files, no need to check and do the serialization yourself:
<target name="jsonFile" xsi:type="File" fileName="${logFileNamePrefix}.json">
<layout xsi:type="JsonLayout">
<attribute name="time" layout="${longdate}" />
<attribute name="level" layout="${level:upperCase=true}"/>
<attribute name="message" layout="${message}" />
</layout>
</target>
The log messages formatting is handled by NLog instead of doing it yourself.
release notes nlog

To add some theory ;)
Another drawback is that I need to make a new TargetWithLayout class for each target that we will use (EventLog, File, WebService and so on).
That's the reasons there are Layouts in NLog. Those are the layouts that could be used in the target, but those are independent of the target.
(don't get confused with Layout Renderers, those ${..} things.)
There are multiple layouts (plain text, CSV, JSON) (see list) , and you could easily add your own layout, analogous to adding a custom Target / Layout renderer, see the wiki

Custom headers and footers with NLog

I am trying to add some targets to NLog that log certain details out to a separate XML file for analysis. I have been trying to get NLog to generate fully valid XML that is in a schema different than the Log4JXmlEventLayout provider.
Towards this end, I've been using a file target that has a header (for the XML declaration and root element opening) and footer (for the root element closing), like so:
<target name="someFileTarget" xsi:type="File" fileName="afile.xml"
header="<?xml version="1.0" encoding="utf-8"?>
<my-events>"
footer="</my-events>">
<layout xsi:type="SimpleLayout">
<text><![CDATA[<event><timestamp>${longdate}</timestamp></event>]]> </text>
</layout>
</target>
However, the footer (closing element) never gets written to the log file, even after the log file gets rolled over. Is there something about this configuration that is incorrect?
I also attempted the LayoutWithHeaderAndFooter provider (as documented here: https://github.com/nlog/NLog/wiki/LayoutWithHeaderAndFooter), but this did not appear to work at all and no events were written to the target.

Adding method name in NLog

I am using NLog and following the recommended pattern of having a log declare on each class, for the purpose of being able to track which class/method has written to the log. I do find this very useful to have a bit of a top level 'stack trace' with each log write.
My code used to look like this:
class SomeClass {
private static readonly Logger logger = LogManager.GetCurrentClassLogger();
void DoStuff() {
logger.Debug("stuff"); }
}
I recently had the requirement my single project to write to 3 separate log files, and to do this, I added multiple loggers and targets as specified here: https://stackoverflow.com/a/21711838/191206
However, now in my log files, I have lost the class level name. It now just writes the log name that I specified in the NLog.config. I've considered simply adding the method name myself with a call to
System.Reflection.MethodBase.GetCurrentMethod(); // use Name property
or using something else in Reflection like this
However, I'm wondering if NLog has something built into this that I'm missing? The Debug() method I only see the ability to write a string, with parameters & optionally formatted..
Is this built into NLog?

There is a built in layout renderer called ${callsite} that you can use to include the call site information (class name, method name and source information) in your log entries:
<targets>
<target
name="task1File"
xsi:type="File"
layout="${callsite} - ${message}"
fileName="${basedir}../Data/debugLog1.txt"
archiveAboveSize ="5000000"
maxArchiveFiles="2"/>
<target
name="task2File"
xsi:type="File"
layout="${callsite} - ${message}"
fileName="${basedir}../Data/debugLog2.txt"
archiveAboveSize ="5000000"
maxArchiveFiles="2"/>
</targets>

Sharing application configurations across a solution

I have a solution which has multiple output projects (a website, and admin tool, and a SOAP API layer).
They each share common projects in the solution (the service layer, data layer etc). In one of these common projects, I am looking to store a config layer.
Right now, we have three seperate appsettings config files for each output project -
development.AppSettings.config
testing.AppSettings.config
production.AppSettings.config
So altogether, there are nine config files. Only one is used in each project, as they are referenced by utilising the configSource attribute in the web.config appsettings node.
Anyhoo, it's getting to be a pain any time we want to add/remove values from our config files, because it means that we have to change all nine files to do this. And here's what I'd like to do:
In the common project, we have three config files as above. These would be set to copy to the output directory, so that each project has a copy of them. These would be the 'base' config.
Then in each project, I would like to have three files again, but they wouldn't necessarily have to contain the same values as the base configs. If they did however, then the base config value would be overridden by the value in the output project config. A form of configuration inheritance, I suppose.
On application start, I'd like to be able to get these two config files - the base config, and the project config file. And then set the app settings accordingly.
What I'm wondering though, is what's a nice way of determining which file to use? Also, I'm wondering if this is a good way of sharing application values across a large solution, and if there's another, perhaps more efficient way of doing it?
If I'm in development mode, then I don't want production.appsettings.config, and vice versa if I'm in production mode.
Is there a simple way to get the mode (development/testing/production) that I'm in before I go off and get the configurations?

You can have one set of files (3 configs) and link/share them in whatever projects you need.
http://www.devx.com/vb2themax/Tip/18855
Hope this helps.

You could use the ConfigurationManager.OpenExeConfiguration static method. This will allow you to work with as many config files as you want.
You may also try creating a custom class to store all of your settings. You could then serialize your object to save it as a file. You could extend your base custom config class to fit all your other projects.

After some careful thought, and a trip to the toilet at 03:30, I came across a solution which works.
Let's say that we have some appSettings in our base config file:
<add key="MyKey1" value="MyValue1" />
<add key="MyKey2" value="MyValue2" />
<!-- And so on... -->
<add key="MyKey5" value="MyValue5" />
And in my output project, I have three appSettings:
<!-- This is used to identify which config to use. -->
<add key="Config" value="Development" />
<!-- Different value to the one in the base -->
<add key="MyKey2" value="NewValue2" />
<!-- This key does not exist in the base config -->
<add key="MyKey6" value="MyValue6" />
In my Application_Start, I have a call to GetConfigs():
ConfigHelper.GetConfig(HostingEnvironment.MapPath("~/bin/BaseConfig"));
And the actual GetConfigs function:
public static void GetConfigs()
{
if (configMode == null)
{
configMode = ConfigurationManager.AppSettings.Get("Config").ToLowerInvariant();
}
//Now load the app settings file and retrieve all the config values.
var config = XElement.Load(#"{0}\AppSettings.{1}.config".FormatWith(directory, configMode))
.Elements("add")
.Select(x => new { Key = x.Attribute("key").Value, Value = x.Attribute("value").Value })
//If the current application instance does not contain this key in the config, then add it.
//This way, we create a form of configuration inheritance.
.Where(x => ConfigurationManager.AppSettings.Get(x.Key) == null);
foreach (var configSetting in config)
{
ConfigurationManager.AppSettings.Set(configSetting.Key, configSetting.Value);
}
}
Now, my output project effectively has the following configuration settings:
<add key="Config" value="Development" />
<add key="MyKey1" value="MyValue1" />
<add key="MyKey2" value="NewValue2" />
<!-- And so on... -->
<add key="MyKey5" value="MyValue5" />
<add key="MyKey6" value="MyValue6" />
Simples!