NLog: reference properties in message - nlog

I am using NLog with structured logging for the first time. I user Serilog in the past, and with that I could write something like this:
Serilog.ILogger logger = CreateSerilogLogger();
logger.ForContext("MyProperty", "Some dummy value")
.Information("This is the value: {MyProperty}"); // prints out: "This is the value: Some dummy value"
but with NLog it seems I cannot reference properties in the log message. This is what I tried to do:
NLog.Logger logger = NLog.LogManager.GetCurrentClassLogger();
logger.WithProperty("MyProperty", "Some dummy value")
.Info("This is the value: {MyProperty}"); // prints out: "This is the value: {MyProperty}" !!!
I know I could simply pass the string inside Info method; this is just an example.
Is there a way to achieve this with NLog? Can properties passed with WithProperty method be linked inside the log message?

Related

Variable visibility in a Groovy Script

I have created a temp.groovy script:
def loggedMessages = [];
def log(message) {
loggedMessages << message;
}
log "Blah"
print loggedMessages.join('\n')
When I run it I get an exception relating to the log method:
groovy.lang.MissingPropertyException: No such property: loggedMessages
Why can't the log method see the loggedMessages variable? I obviously have a fundamental misunderstanding of what's going on. I've tried to read the docs but I can't seem to find the relevant section.
From the comments, as an answer:
The Script class documentation states (in the last section 3.4 Variables) that:
if the variable is declared as in the first example [with a type definition], it is a local variable. It will be declared in the run method that the compiler will generate and will not be visible outside of the script main body. In particular, such a variable will not be visible in other methods of the script
And further: if the variable is undeclared, it goes into the script binding. The binding is visible from the methods [...]
Therefore removing the def from loggedMessages fixes the error:
loggedMessages = [];
def log(message) {
loggedMessages << message;
}
log "Blah"
print loggedMessages.join('\n')
(Alternatively it can be annotated using #groovy.transform.Field as #aetheria pointed out in the comments)

groovy MissingMethodException - parsing through ConfigSlurper

I am trying to parse through some properties file using configslurper.
ENT.adminserver.nodenumber=1
ENT.managedserver.1.host=vserver04
ENT.managedserver.2.host=vserver05
ENT.managedserver.3.host=vserver08
ENT.managedserver.4.host=vserver07
Said properties file. I am trying to read the host names from the properties.
Properties properties = new Properties()
File propertiesFile = new File('DomainBuild.properties')
propertiesFile.withInputStream {properties.load(it)}
def config = new ConfigSlurper().parse(properties)
def domainname="ENT" //will be passed through paremeters
def domain = config.get(domainname)
def managedServerFlow= {
println domain.managedserver
println domain.managedserver.keySet()
domain.managedserver.each {
println it.getClass()
println it.get("1")
}
for (server in domain.managedserver) {
println server.getClass()
println server
}
}
}
the it.get("1") is causing the following error.
No signature of method: java.util.LinkedHashMap$Entry.get() is applicable for argument types: (java.lang.String) values: [1]
Possible solutions: getAt(java.lang.String), grep(), grep(java.lang.Object), wait(), getKey(), any()
I looked through the java and groovy doc and spent few hours without resolution. Please help.
Instead of
println it.get("1")
Try
println it.'1'
Or
println it.getAt("1") // as the exception shows you
Think about what types you are working with. config is a ConfigObject, which you can treat like a map. Its sub-objects domain and domain.managedserver are also ConfigObjects. When you call each on domain.managedserver and pass it a closure that takes no parameters, it gives you a set of Entries. Therefore you can't call it.get("1") because an Entry doesn't have a property called "1". It has key and value. So you can either println "$it.key: $it.value" or
domain.managedserver.each { key, value ->
println value.getClass()
println "$key: $value"
}
or if you want to get the value for key "1" directly:
println domain.managedserver.'1'

Groovy-script in jenkins println output disappears when called inside class environment

The output from println from within a class function is lost.
An example script (outputclass.groovy):
class OutputClass
{
OutputClass()
{
println("Inside class") // This will not show in the console
}
}
println("Outside class") // Only this is shown in the console
output = new OutputClass()
I use Jenkins CLI to execute the groovy script
java -jar ..\jenkins-cli.jar -s JENKINS_SERVER_URL groovy outputclass.groovy
It only outputs this:
Outside class
It seems like the class inmplicitly uses println from System.out.println, and System.out is directed to the log files, but the println outside the class is using something else, which is outputted in the script console. The following code shows the behavior.
System.out.println("First")
println("Second")
Output:
Second
How do I explicitly set the output device to output to the Jenkins script console?
I found the solution myself here http://mriet.wordpress.com.
When the Groovy plugin starts is passes two bindings to the script. From the bindings we can get the out variable. Get it and use out.println to output to the script console, not the plain println.
The script below shows full solution.
import hudson.model.*
// Get the out variable
def out = getBinding().out;
class OutputClass
{
OutputClass(out) // Have to pass the out variable to the class
{
out.println ("Inside class")
}
}
out.println("Outside class")
output = new OutputClass(out)
If you use the skript as a post build step (I'm not shure whether it works with the mentioned CLI) you can use the build in logger:
manager.listener.logger.println("some output")
So in your case something like this may be helpful:
class OutputClass
{
OutputClass(logger) // Have to pass the out variable to the class
{
logger.println ("Inside class")
}
}
output = new OutputClass(manager.listener.logger)
See also Example 10 in Groovy Plugin Doc
Does this mailing list post help?
the output is sent to standard output, so if you check your log file, you
will probably see something like this: INFO [STDOUT] Hello World
if you insist on using system script, you have to pass out variable to
your class, as the binding is not visible inside the class (so it's
passed to standard output). You should use something like this
public class Hello {
static void say(out) {
out << "Hello World "
}
}
println "Started ..."
Hello.say(out)
A simple solution that worked well for me was to add this line on top of each script. This enables usage of traditional println commands all over the code (inside and outside of classes) leaving the code intuitive.
import hudson.model.*
System.out = getBinding().out;
This enables to create log entries like this:
println("Outside class");
class OutputClass {
OutputClass() {
println ("Inside class")
}
}
new OutputClass();
It replaces the default print stream in System.out with the one handed over from Jenkins via bindings.

Log4net EventLogAppender Log Event ID

Is there a way to log an event into the windows event log with a specified eventid per message? I am using log4net v 1.2.10.
Based on what I see in the EventLogAppender source code the following should do the trick:
log4net.ThreadContext.Properties["EventID"] = 5;
Just call this before you write your log messages (if you do not set it for all messages you should remove the "EventID" again from the Properties.
N.B the property key is case sensitive.
When one uses the native .net Event Log APIs in System.Diagnostics, the WriteEntry methods allow setting the eventID and category. In these APIs:
eventID is a 32 bit int, but its value must be between 0 and 65535
category is a 16 bit int, but its value must be positive. If the
event source includes a category resource file, the event viewer will
use the integer category value to lookup a localized “Task category”
string. Otherwise, the integer value is displayed.
The categories must be numbered consecutively, beginning with the
number 1
Log4net supports writing an EventID and a Category, but it isn’t straight forward. When log4net’s EventLogAppender logs an event, it looks at a dictionary of properties. The named properties "EventID" and "Category" are automatically mapped by the EventLogAppender to the corresponding values in the event log. I’ve seen a few good suggested ways to use log4net’s EventLogAppender and set the EventID and Category in the Windows event log.
a. Using log4net’s appender filtering, a filter may be registered that can add the EventID and Category properties. This method has a nice benefit that the standard log4net wrappers are used and so this can be implemented without changing existing logging code. The difficulty in this method is some mechanism has to be created to calculate the EventID and Category from the logged information. For instance, the filter could look at the exception source and map that source to a Category value.
b. Log4net may be extended so custom logging wrappers can be used that can include EventID and Category parameters. Adding EventID is demonstrated in the log4net sample “Extensibility – EventIDLogApp” which is included in the log4net source. In the extension sample a new interface (IEventIDLog) is used that extends the standard ILog interface used by applications to log. This provides new logging methods that include an eventId parameter. The new logging methods add the eventId to the Properties dictionary before logging the event.
public void Info(int eventId, object message, System.Exception t)
{
if (this.IsInfoEnabled)
{
LoggingEvent loggingEvent = new LoggingEvent(ThisDeclaringType, Logger.Repository, Logger.Name, Level.Info, message, t);
loggingEvent.Properties["EventID"] = eventId;
Logger.Log(loggingEvent);
}
}
c. Log4net supports a ThreadContext object that contains a Properties dictionary. An application could set the EventID and Category properties in this dictionary and then when the thread calls a logging method, the values will be used by the EventLogAppender.
log4net.ThreadContext.Properties["EventID"] = 5;
Some helpful references:
Log4net home page
Log4net SDK reference
Log4net samples
Log4net source
Enhancing log4net exception logging
Log4Net Tutorial pt 6: Log Event Context
Customizing Event Log Categories
EventSourceCreationData.CategoryResourceFile Property
Event Logging Elements
EventLog.WriteEntry Method
Well, the solution was to build the extension project "log4net.Ext.EventID" and to use its types: IEventIDLog, EventIDLogImpl and EventIDLogManager.
Another solution is to add a custom Filter as described here: Enhancing log4net exception logging (direct link to the Gist just in case).
As the author points out:
... EventLogAppender uses inline consts to check them. Once they are added they will be used by the mentioned EventLogAppender to mark the given entries with EventId and Category.
The filter implementation will look like the code below (stripped down gist) with the added benefit that if you make GetEventId method public, you can write some tests against it
public class ExceptionBasedLogEnhancer : FilterSkeleton
{
private const string EventLogKeyEventId = "EventID";
public override FilterDecision Decide(LoggingEvent loggingEvent)
{
var ex = loggingEvent.ExceptionObject;
if (ex != null)
{
loggingEvent.Properties[EventLogKeyEventId] = GetEventId(ex);
}
return FilterDecision.Neutral;
}
private static short GetEventId(Exception ex)
{
// more fancy implementation, like getting hash of ex properties
// can be provided, or mapping types of exceptions to eventids
// return no more than short.MaxValue, otherwise the EventLog will throw
return 0;
}
}
Extend ILog.Info() to take an event ID:
public static class LogUtils
{
public static void Info(this ILog logger, int eventId, object message)
{
log4net.ThreadContext.Properties["EventID"] = eventId;
logger.Info(message);
log4net.ThreadContext.Properties["EventID"] = 0; // back to default
}
}
Then call it like this:
using LogUtils;
private static readonly log4net.ILog _logger = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
_logger.Info(3, "First shalt thou take out the Holy Pin, then shalt thou count to three.");

External Content with Groovy BuilderSupport

I've built a custom builder in Groovy by extending BuilderSupport. It works well when configured like nearly every builder code sample out there:
def builder = new MyBuilder()
builder.foo {
"Some Entry" (property1:value1, property2: value2)
}
This, of course, works perfectly. The problem is that I don't want the information I'm building to be in the code. I want to have this information in a file somewhere that is read in and built into objects by the builder. I cannot figure out how to do this.
I can't even make this work by moving the simple entry around in the code.
This works:
def textClosure = { "Some Entry" (property1:value1, property2: value2) }
builder.foo(textClosure)
because textClosure is a closure.
If I do this:
def text = '"Some Entry" (property1:value1, property2: value2)'
def textClosure = { text }
builder.foo(textClosure)
the builder only gets called for the "foo" node. I've tried many variants of this, including passing the text block directly into the builder without wrapping it in a closure. They all yield the same result.
Is there some way I take a piece of arbitrary text and pass it into my builder so that it will be able to correctly parse and build it?
Your problem is that a String is not Groovy code. The way ConfigSlurper handles this is to compile the text into an instance of Script using GroovyClassLoader#parseClass. e.g.,
// create a Binding subclass that delegates to the builder
class MyBinding extends Binding {
def builder
Object getVariable(String name) {
return { Object... args -> builder.invokeMethod(name,args) }
}
}
// parse the script and run it against the builder
new File("foo.groovy").withInputStream { input ->
Script s = new GroovyClassLoader().parseClass(input).newInstance()
s.binding = new MyBinding(builder:builder)
s.run()
}
The subclass of Binding simply returns a closure for all variables that delegates the call to the builder. So assuming foo.groovy contains:
foo {
"Some Entry" (property1:value1, property2: value2)
}
It would be equivalent to your code above.
I think the problem you described is better solved with a slurper or parser.
See:
http://groovy.codehaus.org/Reading+XML+using+Groovy%27s+XmlSlurper
http://groovy.codehaus.org/Reading+XML+using+Groovy%27s+XmlParser
for XML based examples.
In your case. Given the XML file:
<foo>
<entry name='Some Entry' property1="value1" property2="value2"/>
</foo>
You could slurp it with:
def text = new File("test.xml").text
def foo = new XmlSlurper().parseText(text)
def allEntries = foo.entry
allEntries.each {
println it.#name
println it.#property1
println it.#property2
}
Originally, I wanted to be able to specify
"Some Entry" (property1:value1, property2: value2)
in an external file. I'm specifically trying to avoid XML and XML-like syntax to make these files easier for regular users to create and modify. My current solution uses ConfigSlurper and the file now looks like:
"Some Entry"
{
property1 = value1
property2 = value2
}
ConfigSlurper gives me a map like this:
["Some Entry":[property1:value1,property2:value2]]
It's pretty simple to use these values to create my objects, especially since I can just pass the property/value map into the constructor.

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