csharp/src/KubernetesClient.Models/Versioning/VersionConverter.cs

// WARNING: DO NOT LEAVE COMMENTED CODE IN THIS FILE. IT GETS SCANNED BY GEN PROJECT SO IT CAN EXCLUDE ANY MANUALLY DEFINED MAPS

using AutoMapper;
using k8s.Models;
using System.Reflection;

namespace k8s.Versioning
{
    /// <summary>
    /// Provides mappers that converts Kubernetes models between different versions
    /// </summary>
    public static partial class VersionConverter
    {
        static VersionConverter()
        {
            UpdateMappingConfiguration(expression => { });
        }

        public static IMapper Mapper { get; private set; }
        internal static MapperConfiguration MapperConfiguration { get; private set; }

        /// <summary>
        /// Two level lookup of model types by Kind and then Version
        /// </summary>
        internal static Dictionary<string, Dictionary<string, Type>> KindVersionsMap { get; private set; }

        public static Type GetTypeForVersion<T>(string version)
        {
            return GetTypeForVersion(typeof(T), version);
        }

        public static Type GetTypeForVersion(Type type, string version)
        {
            return KindVersionsMap[type.GetKubernetesTypeMetadata().Kind][version];
        }

        public static void UpdateMappingConfiguration(Action<IMapperConfigurationExpression> configuration)
        {
            MapperConfiguration = new MapperConfiguration(cfg =>
            {
                GetConfigurations(cfg);
                configuration(cfg);
            });
            Mapper = MapperConfiguration.CreateMapper();
            KindVersionsMap = MapperConfiguration
                .GetAllTypeMaps()
                .SelectMany(x => new[] { x.Types.SourceType, x.Types.DestinationType })
                .Where(x => x.GetCustomAttribute<KubernetesEntityAttribute>() != null)
                .Select(x =>
                {
                    var attr = GetKubernetesEntityAttribute(x);
                    return new { attr.Kind, attr.ApiVersion, Type = x };
                })
                .GroupBy(x => x.Kind)
                .ToDictionary(x => x.Key, kindGroup => kindGroup
                    .GroupBy(x => x.ApiVersion)
                    .ToDictionary(
                        x => x.Key,
                        versionGroup => versionGroup.Select(x => x.Type).Distinct().Single())); // should only be one type for each Kind/Version combination
        }

        public static object ConvertToVersion(object source, string apiVersion)
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            var type = source.GetType();
            var attr = GetKubernetesEntityAttribute(type);
            if (attr.ApiVersion == apiVersion)
            {
                return source;
            }

            if (!KindVersionsMap.TryGetValue(attr.Kind, out var kindVersions))
            {
                throw new InvalidOperationException($"Version converter does not have any registered types for Kind `{attr.Kind}`");
            }

            if (!kindVersions.TryGetValue(apiVersion, out var targetType) || !kindVersions.TryGetValue(attr.ApiVersion, out var sourceType) || MapperConfiguration.FindTypeMapFor(sourceType, targetType) == null)
            {
                throw new InvalidOperationException($"There is no conversion mapping registered for Kind `{attr.Kind}` from ApiVersion {attr.ApiVersion} to {apiVersion}");
            }

            return Mapper.Map(source, sourceType, targetType);
        }

        private static KubernetesEntityAttribute GetKubernetesEntityAttribute(Type type)
        {
            if (type == null)
            {
                throw new ArgumentNullException(nameof(type));
            }

            var attr = type.GetCustomAttribute<KubernetesEntityAttribute>();
            if (attr == null)
            {
                throw new InvalidOperationException($"Type {type} does not have {nameof(KubernetesEntityAttribute)}");
            }

            return attr;
        }

        internal static void GetConfigurations(IMapperConfigurationExpression cfg)
        {
            AutoConfigurations(cfg);
            ManualConfigurations(cfg);
        }

        private static void ManualConfigurations(IMapperConfigurationExpression cfg)
        {
            cfg.AllowNullCollections = true;
            cfg.DisableConstructorMapping();
            cfg.ForAllMaps((typeMap, opt) =>
            {
                if (!typeof(IKubernetesObject).IsAssignableFrom(typeMap.Types.DestinationType))
                {
                    return;
                }

                var metadata = typeMap.Types.DestinationType.GetKubernetesTypeMetadata();
                opt.ForMember(nameof(IKubernetesObject.ApiVersion), x => x.Ignore());
                opt.ForMember(nameof(IKubernetesObject.Kind), x => x.Ignore());
                opt.AfterMap((from, to) =>
                {
                    var obj = (IKubernetesObject)to;
                    obj.ApiVersion = !string.IsNullOrEmpty(metadata.Group) ? $"{metadata.Group}/{metadata.ApiVersion}" : metadata.ApiVersion;
                    obj.Kind = metadata.Kind;
                });
            });
            cfg.CreateMap<V1Subject, V1beta1Subject>()
                .ForMember(dest => dest.Group, opt => opt.Ignore())
                .ForMember(dest => dest.ServiceAccount, opt => opt.Ignore())
                .ForMember(dest => dest.User, opt => opt.Ignore())
                .ReverseMap();
            cfg.CreateMap<V1Subject, V1beta2Subject>()
                .ForMember(dest => dest.Group, opt => opt.Ignore())
                .ForMember(dest => dest.ServiceAccount, opt => opt.Ignore())
                .ForMember(dest => dest.User, opt => opt.Ignore())
                .ReverseMap();


            cfg.CreateMap<V1HorizontalPodAutoscalerSpec, V2beta2HorizontalPodAutoscalerSpec>()
                .ForMember(dest => dest.Metrics, opt => opt.Ignore())
                .ForMember(dest => dest.Behavior, opt => opt.Ignore())
                .ReverseMap();

            cfg.CreateMap<V1HorizontalPodAutoscalerSpec, V2HorizontalPodAutoscalerSpec>()
                .ForMember(dest => dest.Metrics, opt => opt.Ignore())
                .ForMember(dest => dest.Behavior, opt => opt.Ignore())
                .ReverseMap();


            cfg.CreateMap<V1HorizontalPodAutoscalerStatus, V2beta2HorizontalPodAutoscalerStatus>()
                .ForMember(dest => dest.Conditions, opt => opt.Ignore())
                .ForMember(dest => dest.CurrentMetrics, opt => opt.Ignore())
                .ReverseMap();
            cfg.CreateMap<V1HorizontalPodAutoscalerStatus, V2HorizontalPodAutoscalerStatus>()
                .ForMember(dest => dest.Conditions, opt => opt.Ignore())
                .ForMember(dest => dest.CurrentMetrics, opt => opt.Ignore())
                .ReverseMap();
        }
    }
}