A News Website that uses ASP.NET Core MVC 3.1 and Docker
The solution uses Docker with Windows Containers.
-
DockerDevelopmentModeis set to Regular (yes it's much slower than the Fast Mode) in order to prevent the .NET Docker optimization tools - for maximum encapsulation (https://docs.microsoft.com/en-us/visualstudio/containers/docker-compose-properties?view=vs-2019). -
That means that, in order to run the solution on your PC, you only need Visual Studio (tested with Community 2019 Version 16.5.3 version) and Docker (tested with Docker version 19.03.8, build afacb8b).
-
The projects also uses NPM (internally in the containers). However, Visual Studio by default, restores the npm packages if it finds a reference to NPM in your solution. In our case we use the packages only in the containers, not outside of them. That's why we need to disable the automatic download of the npm packages just as explained here: https://stackoverflow.com/questions/31965425/how-to-disable-visual-studio-2015-and-above-automatic-bower-install-on-solution/42064360#42064360.
-
The current code will run automatically all the migrations on the start of the project and will seed some sample data by the following method:
private void MigrateAndSeed(IApplicationBuilder app)
{
using (var serviceScope = app.ApplicationServices.CreateScope())
{
NewsDbContext newsDbContext = serviceScope.ServiceProvider.GetService<NewsDbContext>();
while (true) // Try to connect until a successful connection, since Docker has some timing issues when initializing the database container.
{
try
{
newsDbContext.Database.Migrate();
break; // if the migrate is successful, the code flow will reach this break
}
catch (Exception ex)
{
Debug.Write(ex.ToString());
Thread.Sleep(15000);
}
}
this.Seed(newsDbContext);
}
}
(it's located in the Startup.cs file in the NewsWebsite project)
If you've completed the steps above. The project should be good and running.
docker container ls- will list all the containers. Grab the Container Id that uses themicrosoft/mssql-server-windows-express:1709image.docker container inspect <containerId>- will show info specific to the container. Grab theIPAddress' value- Connect to the database container just like you would connect to a database on your PC. For example, you can use Microsoft SQL Server Management Studio (tested with version 18). Use SQL Server Authentication, get the password from the
.envfile (located in thedocker-composeproject,saUserPasswordenvironmental variable) and theDatabaseUserenvironmental variable from thedocker-compose.override.yml. You may also need to specify the port - again from the.envfile (newsDatabasePortenvironmental variable), however at the moment we are using port1433(the default database port), so no specifying is needed.
Since we are using the .NET integrated tools for Docker and another assembly for the migrations, the migrations commands have to be more explicit.
dotnet ef migrations add <MigrationName> --startup-project .\NewsWebsite --project .\DataAccess - This will create the migration in the DataAccess assembly.
The custom exception logger uses Docker volumes, so that even if the container is removed, the logs will stay.
By default (depending on your configuration) .NET Core will log the errors to various places (console, file, etc). However, we may need to save the state of the HTTP request, when the error occurred. For example, will the following line of code logger.LogError(exceptionHandlerPathFeature.Error, "An exception with the following input occured: HttpContext.Request.Form: {@Form}, HttpContext.Request.Query: {@Query} at the following path: {@Path}", JsonConvert.SerializeObject(HttpContext.Request.Form), JsonConvert.SerializeObject(HttpContext.Request.Query), exceptionHandlerPathFeature.Path); we will log some of the input values supplied by the user (for easier debugging afterwards).
That's why we use centralized exception handling that redirects to the HomeController class, Error Action method when an unhandled exception occurs. The Error action method logs the error will additional info supplied by us, sets a generic user-friendly error message for the front-end and redirects to the Index action method.
Obviously, we can't use the user-friendly error page and the Developer error page at once. To activate our custom error logging and the user-friendly page, uncomment the following line in the in the Startup.cs file, Configure method: app.UseExceptionHandler("/Home/Error"); and comment out the following line app.UseDeveloperExceptionPage();. If you want to get back your Developer error page, do the opposite.
docker container ls- will list all the containers. Grab the Container Id that uses the image created by the Docker for the current project. (The image name should look like dockercompose13174763213979636238_newswebsite and the container name should be NewsWebsite)docker container inspect <containerId>- will show info specific to the container. In the Mounts section look for a Mount with "Type": "volume"
Should look something like this:
{
"Type": "volume",
"Name": "8fe40fd0acb6c9555a06ed0a5231fa1673db228506b60998685177e1faf42fcc",
"Source": "C:\\ProgramData\\Docker\\volumes\\8fe40fd0acb6c9555a06ed0a5231fa1673db228506b60998685177e1faf42fcc\\_data",
"Destination": "c:\\logs",
"Driver": "local",
"Mode": "",
"RW": true,
"Propagation": ""
},
Get the Source path (if you are navigating to it by using the Windows Explorer you will need to remove the double slashes and leave only one slash as a delimiter).
You will see the NewsWebsiteLogs.txt that contains the logged information.
The log name can be specified from the appsettings.Development.json file, located in the NewsWebsite project.