NetCore-Docker-Heroku

Simple guide to upload a .Net Core web API to Heroku by using Docker.

Technologies

• .Net Core 2.2
• Docker
• Heroku

Before start

This guide is directed for those who have a mininum experience with Docker and a proper environment to run it. Also, the .Net Core 2.2 SDK must be installed in the machine. You can download it here

Heroku

Heroku is a cloud platform that allows applications be hosted at will. It's mostly used for web APIs. Although it has some costs, in this example we will use its free features.

Go to Heroku website and sign up or sign in.

In the Dashboard, click on "Create new app"

Name the app and click on "Create app"

This is your app dashboard.

Install the last version of Heroku CLI here

.Net Core

Download the .Net Core project template from this Github

In the root of the project (where the "apimodelo.netcore.sln" is present), run this command in a terminal:

dotnet publish -c Release

The packages will be downloaded and the project will be built for release. Go to the publish folder:

cd "<ROOT>\apimodelo.netcore.presentation.webapi\bin\Release\netcoreapp2.2\publish\"

Create manually a file called "Dockerfile" without extension inside the folder, edit it with a notepad and copy/paste these lines:

FROM microsoft/dotnet:2.2.0-aspnetcore-runtime
WORKDIR /app
COPY . .
CMD ASPNETCORE_URLS=http://*:$PORT dotnet apimodelo.netcore.presentation.webapi.dll

Docker

Do you remember the name of the app you have created in the Heroku website? It's the time to use it. Replace MYAPP by your app's name in the following commands. Inside the publish folder, run in the terminal:

docker build -t MYAPP .

This will create a image for the .Net Core project with the same name of your app. To authenticate with Heroku, run these commands and follow the instructions:

heroku login

heroku container:login

Tag the image

docker tag MYAPP registry.heroku.com/MYAPP/web

Build the Dockerfile and push the image

heroku container:push web -a MYAPP

Release the image to deploy the app

heroku container:release web -a MYAPP

Access the URL of your app with Swagger

https://MYAPP.herokuapp.com/swagger/index.html

It's Done!

Conclusion

It was really easy to interact with Heroku. You just had to have basic knowledge about Docker and .Net Core.