ASP.Net Core 2 with Postgresql on Linux Part 11: Deploying to Heroku via Docker

In Part I, I discussed the rationale for porting a ASP.Net Core 2 app to my Linux system replacing SQL Server with Postgresql and place it on Heroku. 

With Part II, we transferred the SQL Server data to Postgres.

In Part III, I create the ASP.Net MVC Core 2.x app, from which we will proceed, and get Entity Framework Core installed.

Then in Part IV, I look at the configuration differences between the ASP.Net MVC app that uses SQL Server and the new app, in preparation of porting the old app to use Postgresql.

Part V, we compared the differences in both the projects' structures and ported the existing project code, starting with the data model layer, to the new project. In addition to this, we got the jquery.countdown jquery plugin installed, that is used to implement a JavaScript timer. More on that in a later article. Finally, we used the dotnet ef dbcontext scaffold command that builds a DbContext and entity types for out Postgresql database. And, oh yes, we added the project to github, which frankly should have been done day one.

In Part VI, we got the NUnit testing framework in place in order to test both the new and future code.

Part VII, saw the Service layer setup along with its unit tests.

In Part VIII we imported the Controller classes from the existing app and setup unit tests for them.

Then in Part IX, we migrated the Razor (*.cshtml) files as well as the associated JavaScript, Cascading Style Sheet (CSS), and image files from the existing app.

Part X detailed the Program.cs and Startup.cs files as well as the appsettings.json and project files (*.csproj) content that was then migrated and updated from utilizing SQL Server to accessing Postgresql for data.

Now to deploy this new app to Heroku with Docker from Visual Studio Code on my Ubuntu 16.4 laptop.

First, you will need to download and install the Heroku CLI for your system. Go here for instructions. Then create a Heroku account.

Next, make sure you have Docker installed. Start here.


A quick thing to note is that I renamed my root folder from myApp to myapp as per this. In short, the repo name must be lowercase letters. After renaming it, the following commands to deploy the app worked.

Publish your App - pack the application and its dependencies into a folder for deployment to a hosting system - in this case: .bin/Release/netcoreapp2.0/publish by issuing the following from a command prompt:

 $ dotnet publish -c Release  

Add a file named Dockerfile to the directory where the your app was published for release. In my case, the .bin/Release/netcoreapp2.0/publish directory. Here is the content:

 FROM microsoft/aspnetcore  
 WORKDIR /app  
 COPY . .  
 CMD ASPNETCORE_URLS=http://*:$PORT dotnet myapp.dll  

Build the Docker Image:

 $ docker build -t myapp.dll ./bin/Release/netcoreapp2.0/publish  

Login to Heroku and from your dashboard create a new, free Heroku app to which we will deploy this app.

In the directory of the new app I did the following:

 $ heroku login  
 $ heroku container:login  

Then I tagged the target image that will be deployed:

 $ docker tag myapp.dll:latest registry.heroku.com/newpostgresapp/web  

Now to push the docker image to Heroku:

 $ docker push registry.heroku.com/newpostgresapp/web  

Now, when browsing to the new app URL, it works!

Fell free to create an account by selecting the Register link in the upper-right hand corner of the view. Also, let me know what you think.