DEV Community: Uthman Rahimi

Deploy .NET Core worker Service on Linux

Uthman Rahimi — Wed, 29 Dec 2021 20:00:09 +0000

In the previous post, we learned how to deploy an ASP.NET Core Application on Linux and configure it, in this post we are going to learn about deploying a Worker Service on a Linux machine.

What is Worker Service?

Before talking about our main topic, for those of you who do not know what is a worker service, let's learn about what is worker service.
Worker Service is a built-in feature in .NET Core for creating background services. One example of using Worker Service is running periodical schedules like sending newsletter emails for clients every morning. To learn more about worker service, refer to this link.

We assume that you have created a Worker Service and now you want to deploy it on a Linux machine. First of all, as you learned in the previous article, we need to create a new service file, so use the below command to create a service file:

sudo nano /etc/systemd/system/appbackground.service

and edit its content with the following content to it:

[Unit]
Description=Your description 

[Service]
Type=notify
WorkingDirectory=/home/centos/Desktop/services/

ExecStart=/usr/bin/dotnet /home/centos/Desktop/services/myapp.WorkerServic$


Environment=ASPNETCORE_ENVIRONMENT=Production
[Install]
WantedBy=multi-user.target

Then press ctrl+x to save its content and run the following commands:

sudo systemctl daemon-reload
sudo systemctl start appbackground.service

If you get an error after running sudo systemctl start appbackground.service you will need to add a small change to your worker service project.

Install Microsoft.Extensions.Hosting.Systemd by nuget:

dotnet add package Microsoft.Extensions.Hosting.Systemd

Then change CreateHostBuilder in program.cs like below:

 public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .UseSystemd() // this method must be added
                .ConfigureServices((hostContext, services) =>
                {
                    services.AddHostedService<appWorker>();
                });
    }

After applying this change, get a new publish of your project and put it in the path on the Linux then run start its service.

Deploy ASP.NET CORE Applications on Centos 8

Uthman Rahimi — Sun, 26 Dec 2021 09:09:30 +0000

A couple of weeks ago I needed to deploy an ASP.NET Core application on a centos 8 machine and that was the first time I wanted to use Linux because I had no experience working with Linux, it took me a whole day to finish this task.
In this article, I am going to share whatever you need to know about deploying the asp.net core application on a Linux machine.

First of all, if you are using Windows or Mac OS and you want to have a Linux OS you can use VirtualBox which is free and open-source to run a Linux OS as a gust on your Windows.

In order to install a package, you need to use its command which is like this:

sudo dnf install PackageName

To deploy the ASP.NET Core application we need to install some packages. These packages are required and we have to install them.

Prerequisites:

- SDK
- AspNetCoreRuntime

Open a terminal and run the following command to install them :

sudo dnf install dotnet-sdk-5.0
sudo dnf install aspnetcore-runtime-5.0

PackageManager for CentOs 8 is dnf and yum is for CentOs 7.

Install Nginx

I am using Nginx as a web server but you can choose Apache if you do not want to use Nginx.

So use below command to install nginx

sudo dnf install nginx

After installation is finished, you need to enable and start Nginx. To enable and run Nginx (or any other services) you can use the below command :

sudo systemctl enable nginx

sudo systemctm start nginx

This will enable and start Nginx. But if you want to make sure that it is running, you can check its status by using the below command to see its status.

sudo systemctl status nginx

bear in mind that whenever you want to check the status of a service you can use the above command and I think it's one of the most used commands at the beginning.

If you get a result like below, it means Nginx is working and it's ready to use.

Good job, we have installed all the things that are required to deploy our application, next we have to create a new service to run our application.

Configure Nginx

The next step is configuring Nginx to forward HTTP Requests to our ASP.NET Core application, to do this we should modify its default configuration which is located in /etc/nginx/nginx.conf
run following command to open it and modify it like below:

sudo nano /etc/nginx/nginx.conf

this will open the file and now replace its content with the following :

location / {
    proxy_pass http://0.0.0.0:5000;
    proxy_redirect off;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;

}

To verify if the change we applied is fine and there is no mistake in our syntax, run sudo nginx -t, if the test is successful then we need to reload nginx: sudo nginx -s reload.

If you open a browser and enter http:localhost you should see the default page of Nginx.

Create a new Service

Up until now we installed the required packages and configured Nginx, now we should create a new service to run our application.

To create a new Service File, use the following command :

sudo nano /etc/systemd/system/myapp.service

And add following example to it, then save it by ctrl+x:

[Unit]
Description=Example .NET Web API App running on CentOs 8

[Service]
WorkingDirectory=/var/www/myapp
ExecStart=/usr/bin/dotnet /var/www/myapp/myapp.dll
Restart=always
# Restart service after 10 seconds if the dotnet service crashes:
RestartSec=10
KillSignal=SIGINT
SyslogIdentifier=dotnet-example
User=www-data
Environment=ASPNETCORE_ENVIRONMENT=Production
Environment=DOTNET_PRINT_TELEMETRY_MESSAGE=false

[Install]
WantedBy=multi-user.target

And copy published Project to var/www/myapp.

Note that www-data user must exist, otherwise your service could not be run.

If you have done all the things above, now we should enable and start our service to run the application:

sudo systemctl enable myapp.service
sudo systemctl start myapp.service

After running it, make sure it's running by checking its status sudo systemctl satatus myapp.service , if you get a green running result, it is working and you can access it by entering http:localhost:5000.

Redirect Traffic to 5000

If you want to access your project on port 80 and also access to it from other computers, you will need to add below line in your appSetting.json file:

 "Urls": "http://0.0.0.0:5000",

in this way, we just need to enter Server IP Address in browser, Nginx will redirect to port 5000.

Render html tags based on condition in asp.net core

Uthman Rahimi — Fri, 17 Dec 2021 09:57:18 +0000

If you are using Razor in your applications based on ASP.NET CORE, sometimes you might want to check something and according to that generate HTML tags and show them to clients. For example one of the common things is when we check to know if a user is logged-in or not, if User is not logged-In we would show the Login button otherwise show the Sign-out button.
To accomplish this, we end up with a code like this:

if (User.Identity.IsAuthenticated)
{
    <a href="/Account/Signout">SignOut</a>
}
else {
<a href="/Account/SignIn">SignIn</a>
}

This is fine and does what we want, but there is one more way that I think is much more cleaner and that is using Tag Helper.
After implementing a custom Tag Helper, we can refactor our code and render HTML tags like below:

<a href="/Account/Signout" condition=="@User.Identity.IsAuthenticated">SignOut</a>

As you can see above, there is no if statement and just used condition in HTML tag and passed it a boolean value.

Implementation of Condition tag helper is:


 using Microsoft.AspNetCore.Razor.TagHelpers;

namespace CustomTagHelpers.TagHelpers
{
    [HtmlTargetElement(Attributes = nameof(Condition))]
     public class ConditionTagHelper : TagHelper
    {
        public bool Condition { get; set; }

        public override void Process(TagHelperContext context, TagHelperOutput output)
        {
            if (!Condition)
            {
                output.SuppressOutput();
            }
        }
    }
}

To make this tag helpe available throughout all views, add its namespace to _ViewImports.cshtml

Condition tag helper renders output when passed a true value.

What do you do when you have nothing to do at work.

Uthman Rahimi — Sat, 05 Oct 2019 07:52:53 +0000