rf => rf.ReferenceB == myNameFact and rf => rf.ReferenceB == otherNameFact are the same. The reason the issue goes away as soon as you change or add expressions, is that the opportunity for node sharing goes away. I'm working on fixing it.
I think I have not properly mention my question.
I am writing one rule which will check log level according to their environment like for development log level is debug and for production log level must be Error.
I need you guidance how can I can I write this type of rule because their is no database model so how can I execute match and when condition.
public class LogLevelRule : Rule
{
public static ILog Log = LogManager.GetLogger("MyLogger");
public override void Define()
{
string logLevel = default;
When()
.Query(() => logLevel, q => q
.From(() => GetCurrentLogLevel(Log)));
Then()
.Do(x => Console.WriteLine($"Logging at {logLevel} with {Log.Logger.Name}"));
}
private string GetCurrentLogLevel(ILog logger)
{
if(logger.IsDebugEnabled)
return "Debug";
if(logger.IsInfoEnabled)
return "Info";
if(logger.IsWarnEnabled)
return "Warn";
if(logger.IsErrorEnabled)
return "Error";
if(logger.IsFatalEnabled)
return "Fatal";
return "None";
}
}
We are planning on using NRules as an engine in a multi-tenant environment. As such, we would like to keep the rules repo (and the associated factories) separated. In the same process.
We would setup a dictionary of tenants and their associated rules repo/factory. When a fact is generated in the app, it would pass it to the process. We will search the dictionary for the tenant. We would then use the factory returned for the tenant to setup a session and process the fact.
Do you guys think there are any problems with this design?
3 replies
I just wanted to let everyone know ahead of time. Please let me know if there are any concerns with dropping the support of the lower framework versions.
3 replies
We have a few hundred rules and we are logging RuleFired, RuleFiring, and others. We are logging everything and it is overwhelming, with thousands of events being captured. I am trying to see if there is a way that I could write some logic that captures the rules that fired for each session, captures the rule/rule info in an object, and after the last rule for that session runs can send that log.
Is there a way to tell when the rules sessions has started and is complete and will no longer be called until the next session?
1 reply
Hi all, just getting started with NRules, and we're planning on using it as a constraint mechanism; basically a bunch of rules accept the same input, and I want to get a true/false that all succeeded, or find out that some rule failed. So, it's less about having side effects executed by each rule, but using the rules as a gatekeeper for the next logic I want to execute.
A naive approach would be to use Match to find data which does not fit the rule, and use Do to throw an exception. When I catch the exception, I can log it and return 'false'.
Obviously this isn't the optimal use of exceptions for logic, and I wanted to ask if there's a better approach I'm missing? I was looking for a way to pass back some state from each rule, and check this via the session after it had fired. Is that possible?
2 replies
Also, NRules users google group (https://groups.google.com/g/nrules-users) is now retired in favor of GitHub discussions.
You can also look at the NRules integration tests on the GitHub for more examples.
3 replies
Hi,
we are very interested in NRules possibilities, but our use case is very special and I would like your point of view on what is possible or not.
We are developing a Unity3D app on iOS. This app is consuming data produced by visual editors running on Windows desktop.
We would like to use power of rules engine mechanism, and be able to design rules on windows, and use them in the iOS app.
We have tried to use directly rules engines on the ios but of course we hit the 'compile' limitation for code generation on the type of aot platforms.
My question is : could we eventually think about split NRules behavior in two steps :
on windows use it to compile rules and get a factory
then find a way to serialize this factory instance (as dylib ?), put it on database
then on iOS deserialize it and continue your "Getting Started" example , using compiled rules to avoid code generation on this platform
so, to illustrate it using your "Getting Started" example :
On Windows
//Load rules
var repository = new RuleRepository();
repository.Load(x => x.From(typeof(PreferredCustomerDiscountRule).Assembly));
//Compile rules
var factory = repository.Compile();
Find a way to save compiled rules code
and On iOS :
//retreive compiled rules code
var factory = new FactoryFromSomething()
//Create a working session
var session = factory.CreateSession();
//Load domain model
var customer = new Customer("John Doe") {IsPreferred = true};
var order1 = new Order(123456, customer, 2, 25.0);
var order2 = new Order(123457, customer, 1, 100.0);
//Insert facts into rules engine's memory
session.Insert(customer);
session.Insert(order1);
session.Insert(order2);
//Start match/resolve/act cycle
session.Fire();
Hope this strange use case is clear and hope you can help us :)
1 reply
Hello everyone,
I'm goonna start my thesis soon, my thesis is about integration of rule engine to create BIM models in Revit(AutoCAD). to create models in revit I use revit API(Also implemented in .Net). I have created ASP.Net core application to store all the data required to create a house model in revit. Revit APIs will communicate through REST APIs.
Everytime when I pull the data from database to give information to revit APIs I have to apply rules based on the user configuration of the house and modify the input data based on the rules. So I have started learning NRules and reading the Documentation. I would be very helpful to be sussceful in my thesis by getting suggestion about learning NRules and also some can I achiche everything in applying rules using NRules?
3 replies
using RuleExpert.BimModels;
using RuleExpert.RuleModels;
using System;
namespace RuleExpert
{
class Program
{
static void Main(string[] args)
{
var repository = new RuleRepository();
repository.Load(x => x.From(typeof(FloorLengthAndWidthModifiedRule).Assembly));
var factory = repository.Compile();
var session = factory.CreateSession();
var userInput = new UserInputModel() { HouseName = "flair", IsModefiedLengthAndWidth = true, X = 10, Y = 11 };
session.Insert(userInput);
session.Fire();
Console.WriteLine("Hello World!");
}
}
}namespace RuleExpert.RuleModels
{
[Name("MyRule"), Description("Test rule that demonstrates metadata usage")]
class FloorLengthAndWidthModifiedRule : Rule
{
public override void Define()
{
When()
.Match<UserInputModel>( c => c.IsModefiedLengthAndWidth == true);
Then()
.Do(c=>NotifyChange());
}
public static void NotifyChange()
{
System.Console.WriteLine("Length and width are changed");
}
}
}
