Deploy A .NET API To Heroku Through GitHub Actions

using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace NETToDoDemo.Entities
{
    public class ToDo
    {
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }

        [MaxLength(30)]
        public string Name { get; set; }
        public string? Description { get; set; }

        [Range(1, 3)]
        public int Priority { get; set; }
        public bool IsCompleted { get; set; }
    }
}

using Microsoft.EntityFrameworkCore;
using NETToDoDemo.Entities;

namespace NETToDoDemo.Contexts
{
    public class ToDoContext : DbContext
    {
        public ToDoContext(DbContextOptions<ToDoContext> options) : base(options)
        {
        }

        public DbSet<ToDo> ToDos { get; set; }
    }
}

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "ConnectionStrings": {
    "DefaultConnection": "Host=localhost;Database=ToDoDemo;Username=postgres;Password=12345678"
  }
}

using Microsoft.EntityFrameworkCore;
using NETToDoDemo.Contexts;

var builder = WebApplication.CreateBuilder(args);
var configurationBuilder = new ConfigurationBuilder()
                            .SetBasePath(builder.Environment.ContentRootPath)
                            .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
                            .AddJsonFile($"appsettings.{builder.Environment.EnvironmentName}.json", optional: true)
                            .AddEnvironmentVariables();

builder.Configuration.AddConfiguration(configurationBuilder.Build());

// Add services to the container.

var defaultConnectionString = builder.Configuration.GetConnectionString("DefaultConnection");
builder.Services.AddDbContext<ToDoContext>(options =>
   options.UseNpgsql(defaultConnectionString));

...

2. Create Heroku project and PostgreSQL database

Go to Heroku and create an account if you haven't one. Click in New / Create new app.

Type a name for the app and then Create app.

Go to Resources tab and click in Find more add-ons.

In the search box, type postgres and hit Enter.

Select Heroku Postgres and click on Install Heroku Postgres.

Select the app you created and click on Submit Order Form.

Click in Heroku Postgres.

Go to the Settings tab and click on view credentials.

The same credentials you can see in the Settings tab from the app panel.

Add ASPNETCORE_ENVIRONMENT config var.

In .NET project, in Program.cs, add the following below builder.Services.AddDbContext.

var serviceProvider = builder.Services.BuildServiceProvider();
try
{
    var dbContext = serviceProvider.GetRequiredService<ToDoContext>();
    dbContext.Database.Migrate();
}
catch
{
}

Also, add the following above builder.Services.AddDbContext.

var defaultConnectionString = string.Empty;

if (builder.Environment.EnvironmentName == "Development") {
    defaultConnectionString = builder.Configuration.GetConnectionString("DefaultConnection");
}
else
{
    // Use connection string provided at runtime by Heroku.
    var connectionUrl = Environment.GetEnvironmentVariable("DATABASE_URL");

    connectionUrl = connectionUrl.Replace("postgres://", string.Empty);
    var userPassSide = connectionUrl.Split("@")[0];
    var hostSide = connectionUrl.Split("@")[1];

    var user = userPassSide.Split(":")[0];
    var password = userPassSide.Split(":")[1];
    var host = hostSide.Split("/")[0];
    var database = hostSide.Split("/")[1].Split("?")[0];

    defaultConnectionString = $"Host={host};Database={database};Username={user};Password={password};SSL Mode=Require;Trust Server Certificate=true";
}

Move Dockerfile to the solution directory and update it. Make sure it's as the following structure.

FROM mcr.microsoft.com/dotnet/aspnet:6.0 AS base
WORKDIR /app
EXPOSE 80
EXPOSE 443

FROM mcr.microsoft.com/dotnet/sdk:6.0 AS build
WORKDIR /src
COPY ["NETToDoDemo/NETToDoDemo.csproj", "NETToDoDemo/"]
RUN dotnet restore "NETToDoDemo/NETToDoDemo.csproj"
COPY . .
WORKDIR "/src/NETToDoDemo"
RUN dotnet build "NETToDoDemo.csproj" -c Release -o /app/build

FROM build AS publish
RUN dotnet publish "NETToDoDemo.csproj" -c Release -o /app/publish

FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
CMD ASPNETCORE_URLS=http://*:$PORT dotnet NETToDoDemo.dll

From Heroku, click in your avatar image / Account settings.

Go to API Key, click in reveal. Copy the API Key, we are going to use it in the next section.

3. Create a repository in GitHub and implement CI/CD workflow

Go to your GitHub account, create a repository and push the project. Then, click on the Settings tab.

Go to Secrets tab and click in New repository secret.

Add the following secrets:

• Your Heroku API KEY
• Your Heroku email
• Your Heroku App Name

Click on Actions tab.

Click in set up a workflow yourself.

Replace the main.yml file with the following.

name: Deploy to Heroku

on:
  push:
    branches:
      - main

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: akhileshns/[email protected]
        with:
          heroku_api_key: ${{secrets.HEROKU_API_KEY}}
          heroku_app_name: ${{secrets.HEROKU_APP_NAME}}
          heroku_email: ${{secrets.HEROKU_EMAIL}}
          usedocker: true

This file is responsible to deploy automatically to Heroku using the secrets we created and the Dockerfile in the .NET project.

Click in Start commit and then Commit new file.

We have to wait until the GitHub action finishes. As you can see it was successful.

If you go to the Overview tab in your Heroku app. You can notice it was added something in Dyno information.

You can test your API with the following base URL https://<APP_NAME>.herokuapp.com.

You can find the source code here.

Thanks for reading

Thank you very much for reading, I hope you found this article interesting and may be useful in the future. If you have any questions or ideas that you need to discuss, it will be a pleasure to be able to collaborate and exchange knowledge together.