The configuration file 'appsettings.json' was not found and is not optional

The Azure error is:

.Net Core: Application startup exception: System.IO.FileNotFoundException: The configuration file 'appsettings.json' was not found and is not optional.

So this is a bit vague. I can't seem to nail this down. I'm trying to deploy a .Net Core Web API project to Azure, and I'm getting this error:

:( Oops. 500 Internal Server Error An error occurred while starting the application.

I've deployed plain old .Net WebAPI's and they have worked. I've followed online tutorials and they have worked. But somehow my project is broke. Enabling stdoutLogEnabled on Web.config and looking at the Azure Streaming Logs gives me this:

2016-08-26T02:55:12  Welcome, you are now connected to log-streaming service.
Application startup exception: System.IO.FileNotFoundException: The configuration file 'appsettings.json' was not found and is not optional.
   at Microsoft.Extensions.Configuration.FileConfigurationProvider.Load(Boolean reload)
   at Microsoft.Extensions.Configuration.FileConfigurationProvider.Load()
   at Microsoft.Extensions.Configuration.ConfigurationRoot..ctor(IList`1 providers)
   at Microsoft.Extensions.Configuration.ConfigurationBuilder.Build()
   at Quanta.API.Startup..ctor(IHostingEnvironment env) in D:\Source\Workspaces\Quanta\src\Quanta.API\Startup.cs:line 50
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Extensions.Internal.ActivatorUtilities.ConstructorMatcher.CreateInstance(IServiceProvider provider)
   at Microsoft.Extensions.Internal.ActivatorUtilities.CreateInstance(IServiceProvider provider, Type instanceType, Object[] parameters)
   at Microsoft.Extensions.Internal.ActivatorUtilities.GetServiceOrCreateInstance(IServiceProvider provider, Type type)
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetServiceOrCreateInstance(IServiceProvider provider, Type type)
   at Microsoft.AspNetCore.Hosting.Internal.StartupLoader.LoadMethods(IServiceProvider services, Type startupType, String environmentName)
   at Microsoft.AspNetCore.Hosting.WebHostBuilderExtensions.<>c__DisplayClass1_0.<UseStartup>b__1(IServiceProvider sp)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.FactoryService.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.ScopedCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.SingletonCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass12_0.<RealizeService>b__0(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.EnsureStartup()
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.EnsureApplicationServices()
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication()
Hosting environment: Production
Content root path: D:\home\site\wwwroot
Now listening on: http://localhost:30261
Application started. Press Ctrl+C to shut down.

Ok, that seems simple. It can't find appsettings.json. Looking at my config ( startup.cs ) it seems very well defined. My Startup looks like this:

public class Startup
{
    private static string _applicationPath = string.Empty;
    private static string _contentRootPath = string.Empty;
    public IConfigurationRoot Configuration { get; set; }
    public Startup(IHostingEnvironment env)
    {
        _applicationPath = env.WebRootPath;
        _contentRootPath = env.ContentRootPath;
        // Setup configuration sources.

        var builder = new ConfigurationBuilder()
            .SetBasePath(_contentRootPath)
            .AddJsonFile("appsettings.json")
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);

        if (env.IsDevelopment())
        {
            // This reads the configuration keys from the secret store.
            // For more details on using the user secret store see http://go.microsoft.com/fwlink/?LinkID=532709
            builder.AddUserSecrets();
        }

        builder.AddEnvironmentVariables();
        Configuration = builder.Build();
    }
    private string GetXmlCommentsPath()
    {
        var app = PlatformServices.Default.Application;
        return System.IO.Path.Combine(app.ApplicationBasePath, "Quanta.API.xml");
    }

    // This method gets called by the runtime. Use this method to add services to the container.
    // For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=398940
    public void ConfigureServices(IServiceCollection services)
    {
        var pathToDoc = GetXmlCommentsPath();


        services.AddDbContext<QuantaContext>(options =>
            options.UseSqlServer(Configuration["Data:DefaultConnection:ConnectionString"],
            b => b.MigrationsAssembly("Quanta.API")));

        //Swagger
        services.AddSwaggerGen();
        services.ConfigureSwaggerGen(options =>
        {
            options.SingleApiVersion(new Info
            {
                Version = "v1",
                Title = "Project Quanta API",
                Description = "Quant.API",
                TermsOfService = "None"
            });
            options.IncludeXmlComments(pathToDoc);
            options.DescribeAllEnumsAsStrings();
        });

        // Repositories
        services.AddScoped<ICheckListRepository, CheckListRepository>();
        services.AddScoped<ICheckListItemRepository, CheckListItemRepository>();
        services.AddScoped<IClientRepository, ClientRepository>();
        services.AddScoped<IDocumentRepository, DocumentRepository>();
        services.AddScoped<IDocumentTypeRepository, DocumentTypeRepository>();
        services.AddScoped<IProjectRepository, ProjectRepository>();
        services.AddScoped<IProtocolRepository, ProtocolRepository>();
        services.AddScoped<IReviewRecordRepository, ReviewRecordRepository>();
        services.AddScoped<IReviewSetRepository, ReviewSetRepository>();
        services.AddScoped<ISiteRepository, SiteRepository>();

        // Automapper Configuration
        AutoMapperConfiguration.Configure();

        // Enable Cors
        services.AddCors();

        // Add MVC services to the services container.
        services.AddMvc()
            .AddJsonOptions(opts =>
            {
                // Force Camel Case to JSON
                opts.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
            });
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app)
    {
        app.UseStaticFiles();
        // Add MVC to the request pipeline.
        app.UseCors(builder =>
            builder.AllowAnyOrigin()
            .AllowAnyHeader()
            .AllowAnyMethod());

        app.UseExceptionHandler(
          builder =>
          {
              builder.Run(
                async context =>
                {
                    context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
                    context.Response.Headers.Add("Access-Control-Allow-Origin", "*");

                    var error = context.Features.Get<IExceptionHandlerFeature>();
                    if (error != null)
                    {
                        context.Response.AddApplicationError(error.Error.Message);
                        await context.Response.WriteAsync(error.Error.Message).ConfigureAwait(false);
                    }
                });
          });

        app.UseMvc(routes =>
        {
            routes.MapRoute(
                name: "default",
                template: "{controller=Home}/{action=Index}/{id?}");

            // Uncomment the following line to add a route for porting Web API 2 controllers.
            //routes.MapWebApiRoute("DefaultApi", "api/{controller}/{id?}");
        });


        //Ensure DB is created, and latest migration applied. Then seed.
        using (var serviceScope = app.ApplicationServices
          .GetRequiredService<IServiceScopeFactory>()
          .CreateScope())
        {
            QuantaContext dbContext = serviceScope.ServiceProvider.GetService<QuantaContext>();
            dbContext.Database.Migrate();
            QuantaDbInitializer.Initialize(dbContext);
        }


        app.UseSwagger();
        app.UseSwaggerUi();


    }
}

This works fine locally. But once we publish to Azure, this fails. I'm at a loss. I've created new .Net core project that deploy to Azure just find. But this one project, that I put all my time into to, seems to fail. I'm about ready to copy and paste code out of the project that fails to run and into a new project, but i'm really curious on what's breaking this.

Any ideas?

EDIT: So my Program.cs was:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Hosting;

namespace Quanta.API
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var host = new WebHostBuilder()
                .UseKestrel()
                .UseContentRoot(Directory.GetCurrentDirectory())
                .UseIISIntegration()
                .UseStartup<Startup>()
                .Build();

            host.Run();
        }
    }
}

Edit2: Per Frans, I checked the publishOptions. It was:

"publishOptions": {
"include": [
  "wwwroot",
  "web.config"
]

I took a publishOptions from a working project and changed it to:

 "publishOptions": {
  "include": [
    "wwwroot",
    "Views",
    "Areas/**/Views",
    "appsettings.json",
    "web.config"
  ]
  },

It still gave a 500 error, but it didn't give a stack trace saying it coulding load appsettings.json. Now it was complaining about a connection to SQL. I noticed that my SQL connection string code is mentioned in a lot of RC1 blog posts. RC2 of .Net Core changed it. So I updated it to:

  "Data": {
    "ConnectionStrings": {
      "DefaultConnection": "Server=(localdb)\\MSSQLLocalDB;Database=QuantaDb;Trusted_Connection=True;MultipleActiveResultSets=true"
    }
  },

And changed my startup to:

 services.AddDbContext<QuantaContext>(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"),
        b => b.MigrationsAssembly("Quanta.API")));

Finally, it worked.

I must have followed an older RC1 example and not realized it.