Split remaining service routes

DorkNet.Gateway/Program.cs

@@ -1,6 +1,7 @@
 using DorkNet.Contracts;
 using DorkNet.ServiceDefaults;
 using Microsoft.Extensions.Options;
+using Yarp.ReverseProxy.Configuration;
 
 var builder = WebApplication.CreateBuilder(args);
 builder.Configuration.AddJsonFile("appsettings.Local.json",
@@ -9,6 +10,17 @@ builder.Configuration.AddJsonFile("appsettings.Local.json",
 builder.AddDorkNetServiceDefaults(ServiceNames.Gateway);
 builder.Services.Configure<DorkNetServiceMapOptions>(
     builder.Configuration.GetSection("DorkNet:Services"));
+var serviceMap = builder.Configuration
+    .GetSection("DorkNet:Services")
+    .Get<DorkNetServiceMapOptions>() ?? new DorkNetServiceMapOptions();
+var apexDomain = builder.Configuration["Domain:Apex"]
+    ?? Environment.GetEnvironmentVariable("DORKNET_DOMAIN")
+    ?? "localhost";
+builder.Services
+    .AddReverseProxy()
+    .LoadFromMemory(
+        BuildRoutes(apexDomain, serviceMap),
+        BuildClusters(serviceMap));
 
 var app = builder.Build();
 
@@ -17,6 +29,19 @@ app.MapDorkNetServiceDefaults();
 app.MapGet("/", () => Results.Redirect("/healthz"));
 app.MapGet("/internal/services", (IOptions<DorkNetServiceMapOptions> options) =>
     Results.Ok(options.Value.Endpoints()));
+app.MapGet("/internal/routes", () =>
+    Results.Ok(new
+    {
+        ApexDomain = apexDomain,
+        Routes = BuildRoutes(apexDomain, serviceMap).Select(r => new
+        {
+            r.RouteId,
+            r.ClusterId,
+            r.Match.Hosts,
+            r.Match.Path,
+            r.Order,
+        }),
+    }));
 
 app.MapGet("/internal/services/health", async (
     IOptions<DorkNetServiceMapOptions> options,
@@ -34,6 +59,8 @@ app.MapGet("/internal/services/health", async (
     return Results.Ok(probes);
 });
 
+app.MapReverseProxy();
+
 app.Run();
 
 static async Task<ServiceProbeResponse> ProbeServiceAsync(
@@ -66,3 +93,206 @@ static async Task<ServiceProbeResponse> ProbeServiceAsync(
             checkedAt);
     }
 }
+
+static IReadOnlyList<RouteConfig> BuildRoutes(
+    string apexDomain,
+    DorkNetServiceMapOptions services)
+{
+    var routes = new List<RouteConfig>();
+    var order = 0;
+    var webGroup = DorkNetRouteOwnership.RouteGroups
+        .First(group => group.ServiceName == ServiceNames.Web);
+
+    AddHostRoute(
+        routes,
+        ref order,
+        webGroup.ServiceName,
+        BaseUrlFor(services, webGroup.ServiceName),
+        "web-admin-host",
+        [SubdomainHost("admin", apexDomain)]);
+
+    foreach (var group in DorkNetRouteOwnership.RouteGroups.Where(group => group.ServiceName != ServiceNames.Web))
+    {
+        AddHostRoute(
+            routes,
+            ref order,
+            group.ServiceName,
+            BaseUrlFor(services, group.ServiceName),
+            $"{group.ServiceName}-hosts",
+            group.HostSubdomains.Select(subdomain => SubdomainHost(subdomain, apexDomain)).ToArray());
+    }
+
+    foreach (var group in DorkNetRouteOwnership.RouteGroups)
+    {
+        AddPathRoutes(
+            routes,
+            ref order,
+            group.ServiceName,
+            BaseUrlFor(services, group.ServiceName),
+            group.PathPrefixes);
+    }
+
+    AddHostRoute(
+        routes,
+        ref order,
+        webGroup.ServiceName,
+        BaseUrlFor(services, webGroup.ServiceName),
+        "web-hosts",
+        BuildWebHosts(webGroup, apexDomain));
+
+    if (!string.IsNullOrWhiteSpace(services.Monolith))
+    {
+        routes.Add(Route(ServiceNames.Monolith, "monolith-fallback", "/{**catch-all}", order++));
+    }
+
+    return routes;
+}
+
+static IReadOnlyList<ClusterConfig> BuildClusters(DorkNetServiceMapOptions services)
+{
+    var clusters = new List<ClusterConfig>();
+    foreach (var endpoint in services.Endpoints())
+    {
+        AddCluster(clusters, endpoint.Name, endpoint.BaseUrl);
+    }
+
+    return clusters;
+}
+
+static void AddHostRoute(
+    List<RouteConfig> routes,
+    ref int order,
+    string serviceName,
+    string baseUrl,
+    string routeId,
+    string[] hosts)
+{
+    if (string.IsNullOrWhiteSpace(baseUrl) || hosts.Length == 0)
+    {
+        return;
+    }
+
+    routes.Add(Route(
+        serviceName,
+        routeId,
+        "/{**catch-all}",
+        order++,
+        hosts));
+}
+
+static void AddPathRoutes(
+    List<RouteConfig> routes,
+    ref int order,
+    string serviceName,
+    string baseUrl,
+    IEnumerable<string> paths)
+{
+    if (string.IsNullOrWhiteSpace(baseUrl))
+    {
+        return;
+    }
+
+    foreach (var path in paths)
+    {
+        var routeId = $"{serviceName}-{path.Trim('/').Replace('/', '-').Replace("{**catch-all}", "all")}";
+        var exactPath = NormalizeRoutePrefix(path);
+        routes.Add(Route(serviceName, $"{routeId}-exact", exactPath, order++));
+        routes.Add(Route(serviceName, routeId, $"{exactPath}/{{**catch-all}}", order++));
+    }
+}
+
+static string BaseUrlFor(DorkNetServiceMapOptions services, string serviceName)
+{
+    return serviceName switch
+    {
+        ServiceNames.Identity => services.Identity,
+        ServiceNames.Rooms => services.Rooms,
+        ServiceNames.Notify => services.Notify,
+        ServiceNames.Content => services.Content,
+        ServiceNames.Social => services.Social,
+        ServiceNames.Commerce => services.Commerce,
+        ServiceNames.Platform => services.Platform,
+        ServiceNames.Moderation => services.Moderation,
+        ServiceNames.Web => services.Web,
+        ServiceNames.Monolith => services.Monolith,
+        _ => string.Empty,
+    };
+}
+
+static string[] BuildWebHosts(DorkNetRouteGroup group, string apexDomain)
+{
+    var hosts = new List<string>();
+    if (group.IncludesApexHost)
+    {
+        hosts.Add(apexDomain);
+    }
+
+    hosts.AddRange(group.HostSubdomains
+        .Where(subdomain => !string.Equals(subdomain, "admin", StringComparison.OrdinalIgnoreCase))
+        .Select(subdomain => SubdomainHost(subdomain, apexDomain)));
+
+    return hosts.ToArray();
+}
+
+static string SubdomainHost(string subdomain, string apexDomain)
+{
+    return $"{subdomain}.{apexDomain}";
+}
+
+static string NormalizeRoutePrefix(string path)
+{
+    if (string.IsNullOrWhiteSpace(path) || path == "/")
+    {
+        return "/";
+    }
+
+    return (path[0] == '/' ? path : "/" + path).TrimEnd('/');
+}
+
+static RouteConfig Route(
+    string clusterId,
+    string routeId,
+    string path,
+    int order,
+    string[]? hosts = null)
+{
+    return new RouteConfig
+    {
+        RouteId = routeId,
+        ClusterId = clusterId,
+        Order = order,
+        Match = new RouteMatch
+        {
+            Hosts = hosts,
+            Path = path,
+        },
+        Transforms =
+        [
+            new Dictionary<string, string>
+            {
+                ["RequestHeaderOriginalHost"] = "true",
+            },
+        ],
+    };
+}
+
+static void AddCluster(
+    List<ClusterConfig> clusters,
+    string serviceName,
+    string baseUrl)
+{
+    if (string.IsNullOrWhiteSpace(baseUrl))
+    {
+        return;
+    }
+
+    var address = baseUrl.EndsWith('/') ? baseUrl : baseUrl + "/";
+    clusters.Add(new ClusterConfig
+    {
+        ClusterId = serviceName,
+        Destinations = new Dictionary<string, DestinationConfig>
+        {
+            ["primary"] = new() { Address = address },
+        },
+    });
+}