ASP.NET core load connection string - heroku

Question

I'm building an ASP.NET Core 2 application. I want to deploy my application to Heroku, however, I need to load the connection string from their environment variable $DATABASE_URL. In my startup.cs I have:
namespace LearningSystems
{
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc().AddJsonOptions(options =>
{
options.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
});
services.AddDistributedMemoryCache();
services.AddSession(options =>
{
options.IdleTimeout = TimeSpan.FromMinutes(20);
options.Cookie.HttpOnly = true;
});
SetupDbContext(services);
}
private void SetupDbContext(IServiceCollection services)
{
var conn = Environment.GetEnvironmentVariable("$DATABASE_URL");
var connectionString = Configuration.GetConnectionString("pmf");
services.AddEntityFrameworkNpgsql()
.AddDbContext<pmf_visualizationsContext>(options => options.UseNpgsql(connectionString));
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseExceptionHandler("/Home/Error");
}
app.UseSession();
app.UseStaticFiles();
app.UseMvc(routes =>
{
routes.MapRoute(
name: "Home",
template: "",
defaults: new {controller = "Shell", action = "Index"}
);
});
}
}
}
I want to load a different connection string when I am in a production environment (Heroku).
However, in the method SetupDbContext, I don't know how to find out in which environment I am located. Can anyone tell me what is the correct way to do this?

Answer 1

You can do this by using IHostingEnvironment and Getting the current environment.
https://learn.microsoft.com/en-us/aspnet/core/fundamentals/environments1
[Kindly refer to this link for help]