/*
* Copyright (c) 2024 Vaughn Nugent
*
* Library: VNLib
* Package: VNLib.Plugins.Essentials.ServiceStack
* File: ServiceDomain.cs
*
* ServiceDomain.cs is part of VNLib.Plugins.Essentials.ServiceStack which is part of the larger
* VNLib collection of libraries and utilities.
*
* VNLib.Plugins.Essentials.ServiceStack is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 2 of the
* License, or (at your option) any later version.
*
* VNLib.Plugins.Essentials.ServiceStack is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see https://www.gnu.org/licenses/.
*/
using System;
using System.Net;
using System.Linq;
using System.Collections.Generic;
using VNLib.Utils.Extensions;
namespace VNLib.Plugins.Essentials.ServiceStack
{
///
/// Represents a domain of services and thier dynamically loaded plugins
/// that will be hosted by an application service stack
///
public sealed class ServiceDomain
{
private readonly LinkedList _serviceGroups = new();
///
/// Gets all service groups loaded in the service manager
///
public IReadOnlyCollection ServiceGroups => _serviceGroups;
///
/// Uses the supplied callback to get a collection of virtual hosts
/// to build the current domain with
///
/// The callback method to build virtual hosts
/// A value that indicates if any virtual hosts were successfully loaded
public bool BuildDomain(Action> hostBuilder)
{
//LL to store created hosts
LinkedList hosts = new();
//build hosts
hostBuilder.Invoke(hosts);
return FromExisting(hosts);
}
///
/// Builds the domain from an existing enumeration of virtual hosts
///
/// The enumeration of virtual hosts
/// A value that indicates if any virtual hosts were successfully loaded
public bool FromExisting(IEnumerable hosts)
{
//Get service groups and pass service group list
CreateServiceGroups(_serviceGroups, hosts);
return _serviceGroups.Any();
}
private static void CreateServiceGroups(ICollection groups, IEnumerable hosts)
{
//Get distinct interfaces
IPEndPoint[] interfaces = hosts.Select(static s => s.TransportInfo.TransportEndpoint).Distinct().ToArray();
//Select hosts of the same interface to create a group from
foreach (IPEndPoint iface in interfaces)
{
IEnumerable groupHosts = hosts.Where(host => host.TransportInfo.TransportEndpoint.Equals(iface));
//Find any duplicate hostnames for the same service gorup
IServiceHost[] overlap = groupHosts.Where(vh => groupHosts.Select(static s => s.Processor.Hostname).Count(hostname => vh.Processor.Hostname == hostname) > 1).ToArray();
if(overlap.Length > 0)
{
throw new ArgumentException($"The hostname '{overlap.Last().Processor.Hostname}' is already in use by another virtual host");
}
//init new service group around an interface and its roots
ServiceGroup group = new(iface, groupHosts);
groups.Add(group);
}
}
///
/// Tears down the service domain by destroying all s. This instance may be rebuilt
/// if this method returns successfully.
///
public void TearDown()
{
//Manually cleanup if unload missed data
_serviceGroups.TryForeach(static sg => sg.UnloadAll());
//empty service groups
_serviceGroups.Clear();
}
}
}