gelf4net

gelf4net is a log4net adapter that formats logs to the GELF specification and makes it easy to send them over Udp or Amqp.

Installation

You can install the latest stable release using the nuget package gelf4net.
If you want to use the daily builds you can install the gelf4net-ci package.

Configuration

gelf4net gives you the ability to log messages either through Udp or Amqp.

Sample Configuration

<?xml version="1.0"?>
<configuration>
	<configSections>
		<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,Log4net"/>
	</configSections>

	<log4net>
		<root>
		  <level value="ALL"/>
		  <appender-ref ref="GelfUdpAppender"/>
		  <appender-ref ref="GelfAmqpAppender"/>
		</root>

		<appender name="GelfUdpAppender" type="Gelf4net.Appender.GelfUdpAppender, Gelf4net">
		  <remoteAddress value="127.0.0.1"/>
		  <remotePort value="12201" />
		  <layout type="Gelf4net.Layout.GelfLayout, Gelf4net">
			<param name="AdditionalFields" value="app:RandomSentence,version:1.0,Level:%level" />
			<param name="Facility" value="RandomPhrases" />
			<param name="IncludeLocationInformation" value="true"/>
			<!-- Sets the full_message and short_message to the specified pattern-->
			<!--<param name="ConversionPattern" value="[%t] %c{1} - %m" />-->
		  </layout>
		</appender>

	<appender name="GelfUdpHostNameAppender" type="Gelf4net.Appender.GelfUdpAppender, Gelf4net">
		  <remoteHostName value="my.graylog2.local"/>
		  <remotePort value="12201" />
		  <layout type="Gelf4net.Layout.GelfLayout, Gelf4net">
			<param name="AdditionalFields" value="app:RandomSentence,version:1.0,Level:%level" />
			<param name="Facility" value="RandomPhrases" />
			<param name="IncludeLocationInformation" value="true"/>
			<!-- Sets the full_message and short_message to the specified pattern-->
			<!--<param name="ConversionPattern" value="[%t] %c{1} - %m" />-->
		  </layout>
		</appender>

		<appender name="GelfAmqpAppender" type="Gelf4net.Appender.GelfAmqpAppender, Gelf4net">
		  <remoteAddress value="127.0.0.1" />
		  <remotePort value="5672" />
		  <username value="guest" />
		  <password value="guest" />
		  <virtualHost value="/" />
		  <exchange value="sendExchange" />
		  <key value="key" />
		  <layout type="Gelf4net.Layout.GelfLayout, Gelf4net">
			<param name="AdditionalFields" value="app:RandomSentence,version:1.0,Level:%level" />
			<param name="Facility" value="RandomPhrases" />
			<param name="IncludeLocationInformation" value="true"/>
			<!-- Sets the full_message and short_message to the specified pattern-->
			<!--<param name="ConversionPattern" value="[%t] %c{1} - %m" />-->
		  </layout>
		</appender>
	</log4net>
</configuration>

Additional Properties

There are several ways that additional properties can be added to a log.

Configuration
Any static information can be set through configuration by adding a comma separated list of key:value pairs.
You can also use conversion patterns like you would if you were using the PatternLayout class:

<layout type="Gelf4net.Layout.GelfLayout, Gelf4net">
    <param name="AdditionalFields" value="app:RandomSentence,version:1.0,Level:%level" />
</layout>

This will add the following fields to your GELF log:

{
    ...
	"_app":"RandomSentence",
	"_version":"1.0",
	"_Level":"DEBUG",
	...
}

You can also use your own custom field and key/value separators to deal with the case when the additional fields contain commas or colons

<layout type="Gelf4net.Layout.GelfLayout, Gelf4net">
    <param name="AdditionalFields" value="app¬:¬RandomSentence¬|¬version:1.0¬|¬Level¬:¬%level" />
	<param name="FieldSeparator" value="¬|¬" />
    <param name="KeyValueSeparator" value="¬:¬" />  
</layout>

Custom Properties
Any properties you add to the log4net.ThreadContext.Properties object will automatically be added to the message as additional fields

log4net.ThreadContext.Properties["TraceID"] = Guid.NewGuid();

This will be added to the log:

{
    ...
    "_TraceID":"3449DDF8-C3B4-46DD-8B83-0BDF1ABC92E2",
    ...
}

Custom Objects
You can use custom objects to log additional fields to the output. Here is an example:

_logger.Debug(new {
    Type = "Request",
    Method = request.Method,
    Url = request.Url
});

This will add the following additional fields to the output:

{
    ...
    "_Type":"Request",
    "_Method":"GET",
    "_Url":"http://whatever.com/gelf",
    ...
}

Under the hood the GelfLayout class takes any object that is not a string and adds it's public properties to a dictionary and converts their values in to strings. You can also pass in a dictionary directly and get the same output. When passing in a dictionary rather than using the public properties of the object it uses the Key/Value pairs stored internally.

_logger.Debug(new Dictionary<string,string>{
    { "Type", "Request" },
    { "Method", request.Method },
    { "Url", request.Url.ToString() }
});

Formatting Messages

If you are just logging a simple string then that message will show up in the full_message and be truncated to 250 characters in the short_message field.

_logger.Debug("This is a ridiculously short message but pretending it's longer than 250 characters");

Pretending the previous message is longer than 250 characters, this will be your output:

{
    ...
    "full_message":"This is a ridiculously short message but pretending it's longer than 250 characters",
    "short_message":"This is a ridiculously short message but pretending",
    ...
}

If you want to format your message using a conversion pattern you can do so by specifying the ConversionPattern parameter.
Again you can specify all the same parameters that you would if you were using the PatternLayout.

		  <layout type="Gelf4net.Layout.GelfLayout, Gelf4net">
			<param name="ConversionPattern" value="[%t] %c{1} - %m" />
		  </layout>

You can also specify the message when logging custom objects:

_logger.Debug(new Dictionary<string,string>{
    { "Type", "Request" },
    { "Method", request.Method },
    { "Message", request.RawUrl }
    { "ShortMessage", request.Url.ToString() }
});

If the custom object does not have a Message or ShortMessage field than the message will be the output of the ToString() of that object.

License