SwaggerEndPoints configuration section is missing or empty exception

I am using SwaggerForOcelot with .net core 3.1 for api gateway.

Our ocelot json is divided into modules like below:-

ocelot.call-log.json ocelot.column-chooser.json ocelot.contact-list.json ocelot.documentation.json ocelot.global.json ocelot.inventory-list.json ocelot.json <= this is generated automatically. ocelot.swagger.json <=define here swagger related configuration , pls find below

{ “ReRoutes”: [ { “DownstreamPathTemplate”: “/api/{everything}”, “DownstreamScheme”: “http”, “DownstreamHostAndPorts”: [ { “Host”: “xx.xx.xx.xx”, “Port”: 6004 } ], “UpstreamPathTemplate”: “{everything}”, “UpstreamHttpMethod”: [ “GET”, “POST”, “PUT”, “DELETE” ], “SwaggerKey”: “all” } ], “SwaggerEndPoints”: [ { “Key”: “all”, “Config”: [ { “Name”: “Test API V1”, “Version”: “v1”, “Url”: “http://xx.xx.xx.xx:6004/swagger/v1/swagger.json” } ] } ] }

On running it giving exception on below line:-

app.UseSwaggerForOcelotUI(Configuration, opt => { opt.PathToSwaggerGenerator = “/swagger/docs”; });

Exception details:- at Microsoft.AspNetCore.Builder.BuilderExtensions.GetConfiguration(IConfiguration configuration) at Microsoft.AspNetCore.Builder.BuilderExtensions.<>c__DisplayClass1_0.<UseSwaggerForOcelotUI>b__0(SwaggerUIOptions c) at Microsoft.AspNetCore.Builder.SwaggerUIBuilderExtensions.UseSwaggerUI(IApplicationBuilder app, Action1 setupAction) at Microsoft.AspNetCore.Builder.BuilderExtensions.UseSwaggerForOcelotUI(IApplicationBuilder app, IConfiguration configuration, Action1 setupAction) at SMARTS2.ApiGateway.Startup.Configure(IApplicationBuilder app, IWebHostEnvironment env) in C:\Users\rajesh.agrawal\source\repos\SMARTS 2.0 API\SMARTS2.0\SMARTS2.ApiGateway\Startup.cs:line 63 at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at Microsoft.AspNetCore.Hosting.ConfigureBuilder.Invoke(Object instance, IApplicationBuilder builder) at Microsoft.AspNetCore.Hosting.ConfigureBuilder.<>c__DisplayClass4_0.<Build>b__0(IApplicationBuilder builder) at Microsoft.AspNetCore.Hosting.ConventionBasedStartup.Configure(IApplicationBuilder app)

Let me know why this error coming ?

[amadard]

Sure thing! I will get it done this weekend.

[amadard]

First step is to replace the Ocelot FileReRoute, which is why the SwaggerKey is being dropped:

	public class SwaggerFileReRoute: FileReRoute
	{
		public string SwaggerKey { get; set; }
	}

Then we need to replace the FileConfiguration to have the ReRoutes property use our new SwaggerFileReRoute model. This is a full redo, since we cant inherit and replace the ReRoutes property.

	public class SwaggerFileConfiguration
	{
		public List<SwaggerFileReRoute> ReRoutes { get; set; } = new List<SwaggerFileReRoute>();

		public List<FileDynamicReRoute> DynamicReRoutes { get; set; } = new List<FileDynamicReRoute>();

		// Seperate field for aggregates because this let's you re-use ReRoutes in multiple Aggregates
		public List<FileAggregateReRoute> Aggregates { get; set; } = new List<FileAggregateReRoute>();

		public FileGlobalConfiguration GlobalConfiguration { get; set; } = new FileGlobalConfiguration();

		public List<SwaggerEndPointOptions> SwaggerEndPoints { get; set; } = new List<SwaggerEndPointOptions>();
	}

Then we are replacing the AddOcelot(this IConfigurationBuilder builder, string folder, IWebHostEnvironment env) method with our own version that properly uses the above models, and handles the SwaggerEndPoints. This is copy and update of the AddOcelot.

        public static IConfigurationBuilder AddOcelotWithSwaggerSupport(this IConfigurationBuilder builder, string folder, IWebHostEnvironment env)
        {
            string primaryConfigFile = "ocelot.json";

            string globalConfigFile = "ocelot.global.json";

            string SwaggerEndPointsConfigFile = "ocelot.SwaggerEndPoints.json";

            string subConfigPattern = @"^ocelot\.(.*?)\.json$";

            string excludeConfigName = env?.EnvironmentName != null ? $"ocelot.{env.EnvironmentName}.json" : string.Empty;

            var reg = new Regex(subConfigPattern, RegexOptions.IgnoreCase | RegexOptions.Singleline);

            var files = new DirectoryInfo(folder)
                .EnumerateFiles()
                .Where(fi => reg.IsMatch(fi.Name) && (fi.Name != excludeConfigName))
                .ToList();

            var fileConfiguration = new SwaggerFileConfiguration();

            foreach (var file in files)
            {
                if (files.Count > 1 && file.Name.Equals(primaryConfigFile, StringComparison.OrdinalIgnoreCase))
                {
                    continue;
                }

                var lines = File.ReadAllText(file.FullName);

                var config = JsonConvert.DeserializeObject<SwaggerFileConfiguration>(lines);

                if (file.Name.Equals(globalConfigFile, StringComparison.OrdinalIgnoreCase))
                {
                    fileConfiguration.GlobalConfiguration = config.GlobalConfiguration;
                }

                if (file.Name.Equals(SwaggerEndPointsConfigFile, StringComparison.OrdinalIgnoreCase))
                {
                    fileConfiguration.SwaggerEndPoints = config.SwaggerEndPoints;
                }

                fileConfiguration.Aggregates.AddRange(config.Aggregates);
                fileConfiguration.ReRoutes.AddRange(config.ReRoutes);
            }

            var json = JsonConvert.SerializeObject(fileConfiguration);

            File.WriteAllText(primaryConfigFile, json);

            builder.AddJsonFile(primaryConfigFile, false, false);

            return builder;
        }

This requires your SwaggerEndPoints be in a file named “ocelot.SwaggerEndPoints.json”.

Then you call that extension method in replacement of AddOcelot()

  webBuilder
  .ConfigureAppConfiguration((hostingContext, config) =>
  {
	  config
		  .SetBasePath(hostingContext.HostingEnvironment.ContentRootPath)
		  .AddOcelotWithSwaggerSupport(folder, hostingContext.HostingEnvironment);
  })