Setup

Prerequisite software: Docker

Creating a projects

Create a new console application project in a new folder using dotnet command.

> dotnet new console --name TaskManager.Service

Also, create a Web API project using the same folder for communicating with our Service. Then add both projects to the common solution.

 dotnet new webapi --name TaskManager.Api

Then we add the Cronus dependency.

cd TaskManager.Api
dotnet add package Cronus

cd ../TaskManager.Service
dotnet add package Cronus
dotnet add package Cronus.Transport.RabbitMQ
dotnet add package Cronus.Persistence.Cassandra
dotnet add package Cronus.Serialization.NewtonsoftJson
dotnet add package Microsoft.Extensions.Hosting

This is the minimum set of packages for our Cronus host to work.

Run docker images

• Setup Cassandra (Container memory is limited to 2GB): docker run --restart=always -d --name cassandra -p 9042:9042 -p 9160:9160 -p 7199:7199 -p 7001:7001 -p 7000:7000 cassandra

• Setup RabbitMq (Container memory is limited to 512MB): docker run --restart=always -d --hostname node1 -e RABBITMQ_NODENAME=docker-UNIQUENAME-rabbitmq --name rabbitmq -p 15672:15672 -p 5672:5672 elders/rabbitmq:3.8.3

Setup configuration file

Add appsettings.json with the following configuration into the project folder.

//This should be int the Service and in the Api.

appsettings.json

{
  "Cronus": {
    "BoundedContext": "taskmanager",
    "Tenants": [ "tenant" ],
    "Transport": {
        "RabbitMQ": {
            "Server": "127.0.0.1",
            "VHost": "taskmanager"
        },
        "PublicRabbitMQ": [
            {
                "Server": "127.0.0.1",
                "VHost": "unicom-public",
                "FederatedExchange": {
                    "UpstreamUri": "guest:guest@localhost:5672",
                    "VHost": "unicom-public",
                    "UseSsl": false,
                    "MaxHops": 1
                }
            }
        ]
    },
    "Persistence": {
        "Cassandra": {
            "ConnectionString": "Contact Points=127.0.0.1;Port=9042;Default Keyspace=taskmanager_es"
        }
    },
    "Projections": {
        "Cassandra": {
            "ConnectionString": "Contact Points=127.0.0.1;Port=9042;Default Keyspace=taskmanager_projections"
        }
    },
    "Cluster": {
        "Consul": {
            "Address": "127.0.0.1"
        }
    },
    "AtomicAction": {
        "Redis": {
            "ConnectionString": "127.0.0.1:6379"
        }
    }
}
}

You can also see how the Cronus application can be configured in more detail in Configuration.

This is the code that your Program.cs in TaskManager.Service should contain.

Program.cs

using Cronus11Service;
using Elders.Cronus;

IHost host = Host.CreateDefaultBuilder(args)
        .ConfigureServices((hostContext, services) =>
        {
            services.AddHostedService<Worker>();
            services.AddCronus(hostContext.Configuration);

        })
        .UseDefaultServiceProvider((context, options) =>
        {
            options.ValidateScopes = context.HostingEnvironment.IsDevelopment();
            options.ValidateScopes = false;
            options.ValidateOnBuild = false;
        })
        .Build();

host.Run();

This is the code that you should add in the Program.cs in TaskManager.Api.

Program.cs

builder.Services.AddCronus(builder.Configuration);

builder.Host.UseDefaultServiceProvider((context, options) =>
{
    options.ValidateScopes = context.HostingEnvironment.IsDevelopment();
    options.ValidateScopes = false;
    options.ValidateOnBuild = false;
}
);

....

app.UseCronusAspNetCore();

F5

Ensure that service has been started properly.