Publish not getting connection string from appsettings.production.json

Question

I am not able to get my published ASP.net Core application to switch to using the connection string in my appsettings.production.json file.

I have setup the launchSettings to use the ASPNETCORE_ENVIRONMENT environment variable for my Development and Production profiles. When I switch the profiles and run them in visual studio, my connection string changes properly.

When I run the published app on my Ubuntu server, it does not switch. I have set the ASPNETCORE_ENVIRONMENT variable to "Production" on my server. I have also verified that both the appSettings.json and appSettings.production.json exist in the root directory for the application.

My appsettings.json file:

{
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Debug",
      "System": "Information",
      "Microsoft": "Information"
    }
  },
  "ConnectionStrings": {
    "DefaultConnection": "server=localhost;user id=root;password=dev;database=testdb;sslmode=none",
  }
}

my appsettings.production.json file:

{
  "ConnectionStrings": {
    "DefaultConnection": "server=localhost;user id=root;password=prod;database=testdb;sslmode=none"
  }
}

My launchSettings.json file:

{
  "iisSettings": {
    "windowsAuthentication": false,
    "anonymousAuthentication": true,
    "iisExpress": {
      "applicationUrl": "http://localhost:50824/",
      "sslPort": 0
    }
  },
  "profiles": {
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "launchUrl": "home/index",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    },
    "IIS Express (Production)": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "launchUrl": "home/index",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Production"
      }
    }
  }
}

My Startup.cs:

public Startup(IHostingEnvironment env)
{
    var builder = new ConfigurationBuilder()
        .SetBasePath(env.ContentRootPath)
        .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
        .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);

    if (env.IsEnvironment("Development"))
    {
        // This will push telemetry data through Application Insights pipeline faster, allowing you to view results immediately.
        builder.AddApplicationInsightsSettings(developerMode: true);
    }

    builder.AddEnvironmentVariables();
    Configuration = builder.Build();


    Console.WriteLine("Root Path: " + env.ContentRootPath);
    Console.WriteLine("Connection String: " + Configuration.GetConnectionString("DefaultConnection"));
}

I have referenced these questions already but no luck:

asp.net core 1 appsettings.production.json not updating connection strings

dotnet publish doesn´t publish correct appsettings.{env.EnvironmentName}.json

Answer 1

As it turns out this "Note" in the official documentation is VERY important:

On Windows and macOS, the specified environment name is case insensitive. Whether you set the variable to Development or development or DEVELOPMENT the results will be the same. However, Linux is a case sensitive OS by default. Environment variables, file names and settings should assume case sensitivity for best practice.

Mainly the line "Linux is a case sensitive OS by default"!!!!! Whoops :)

Once I changed my environment variable to "production" instead of "Production", it worked.

Further Explanation:

The key is understanding this line of code in the Startup.cs Startup method:

.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);

It replaces the {env.EnvironmentName} with your environment variable, so if you are operating in linux, it needs to match your file name exactly. In my case "appSettings.production.json" so ASPNETCORE_ENVIRONMENT must be "production".