feat(crd generation): add validators

this closes #8. added various validation
attributes for the crd generation. described
in the readme.

Author: Christoph Bühler

README.md

@@ -68,6 +68,22 @@ public class Foo : CustomKubernetesEntity<FooSpec>
 
 Now a CRD for your "Foo" class is generated on build.
 
+#### Validation
+
+You can use the various validator attributes to customize your crd:
+
+(all attributes are on properties with the exception of the Description)
+
+- `Description`: Describe the property or class
+- `ExternalDocs`: Add a link to an external documentation
+- `Items`: Customize MinItems / MaxItems and if the items should be unique
+- `Lenght`: Customize the length of something
+- `MultipleOf`: A number should be a multiple of
+- `Pattern`: A valid ECMA script regex (e.g. `/\d*/`)
+- `RangeMaximum`: The maximum of a value (with option to exclude the max itself)
+- `RangeMinimum`: The minimum of a value (with option to exclude the min itself)
+- `Required`: The field is listed in the required fields
+
 ### Write Controllers
 
 ```csharp

src/KubeOps/KubeOps.csproj

@@ -28,6 +28,7 @@
         <PackageReference Include="KubernetesClient" Version="2.0.21" />
         <PackageReference Include="McMaster.Extensions.CommandLineUtils" Version="3.0.0" />
         <PackageReference Include="McMaster.Extensions.Hosting.CommandLine" Version="3.0.0" />
+        <PackageReference Include="Namotion.Reflection" Version="1.0.11" />
         <PackageReference Include="YamlDotNet" Version="8.1.1" />
     </ItemGroup>
 
@@ -40,4 +41,10 @@
         </Content>
     </ItemGroup>
 
+    <ItemGroup>
+        <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
+            <_Parameter1>$(MSBuildProjectName).Test</_Parameter1>
+        </AssemblyAttribute>
+    </ItemGroup>
+
 </Project>

src/KubeOps/Operator/Commands/Generators/CrdGenerator.cs

@@ -1,13 +1,11 @@
 using System;
 using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations;
 using System.IO;
 using System.Linq;
 using System.Reflection;
 using System.Text;
 using System.Threading.Tasks;
 using k8s.Models;
-using KubeOps.Operator.Entities;
 using KubeOps.Operator.Entities.Extensions;
 using KubeOps.Operator.Entities.Kustomize;
 using KubeOps.Operator.Serialization;
@@ -18,18 +16,6 @@ namespace KubeOps.Operator.Commands.Generators
     [Command("crd", "crds", Description = "Generates the needed CRD for kubernetes.")]
     internal class CrdGenerator : GeneratorBase
     {
-        private const string Integer = "integer";
-        private const string Number = "number";
-        private const string String = "string";
-        private const string Boolean = "boolean";
-        private const string Object = "object";
-
-        private const string Int32 = "int32";
-        private const string Int64 = "int64";
-        private const string Float = "float";
-        private const string Double = "double";
-        private const string DateTime = "date-time";
-
         private readonly EntitySerializer _serializer;
 
         public CrdGenerator(EntitySerializer serializer)
@@ -47,15 +33,19 @@ public async Task<int> OnExecuteAsync(CommandLineApplication app)
             {
                 Directory.CreateDirectory(OutputPath);
 
-                var kustomizeOutput = Encoding.UTF8.GetBytes(_serializer.Serialize(new KustomizationConfig
-                {
-                    Resources = crds
-                        .Select(crd => $"{crd.Metadata.Name.Replace('.', '_')}.{Format.ToString().ToLower()}").ToList(),
-                    CommonLabels = new Dictionary<string, string>
-                    {
-                        {"operator-element", "crd"},
-                    },
-                }, Format));
+                var kustomizeOutput = Encoding.UTF8.GetBytes(
+                    _serializer.Serialize(
+                        new KustomizationConfig
+                        {
+                            Resources = crds
+                                .Select(crd => $"{crd.Metadata.Name.Replace('.', '_')}.{Format.ToString().ToLower()}")
+                                .ToList(),
+                            CommonLabels = new Dictionary<string, string>
+                            {
+                                { "operator-element", "crd" },
+                            },
+                        },
+                        Format));
                 await using var kustomizationFile =
                     File.Open(Path.Join(OutputPath, $"kustomization.{Format.ToString().ToLower()}"), FileMode.Create);
                 await kustomizationFile.WriteAsync(kustomizeOutput);
@@ -69,8 +59,11 @@ public async Task<int> OnExecuteAsync(CommandLineApplication app)
 
                 if (!string.IsNullOrWhiteSpace(OutputPath))
                 {
-                    await using var file = File.Open(Path.Join(OutputPath,
-                        $"{crd.Metadata.Name.Replace('.', '_')}.{Format.ToString().ToLower()}"), FileMode.Create);
+                    await using var file = File.Open(
+                        Path.Join(
+                            OutputPath,
+                            $"{crd.Metadata.Name.Replace('.', '_')}.{Format.ToString().ToLower()}"),
+                        FileMode.Create);
                     await file.WriteAsync(Encoding.UTF8.GetBytes(output));
                 }
                 else
@@ -90,151 +83,12 @@ public static IEnumerable<V1CustomResourceDefinition> GenerateCrds()
                 throw new Exception("No Entry Assembly found.");
             }
 
-            var result = new List<V1CustomResourceDefinition>();
-            foreach (var entityType in GetTypesWithAttribute<KubernetesEntityAttribute>(assembly))
-            {
-                var entityDefinition = CustomEntityDefinitionExtensions.CreateResourceDefinition(entityType);
-
-                var crd = new V1CustomResourceDefinition(
-                    new V1CustomResourceDefinitionSpec(),
-                    $"{V1CustomResourceDefinition.KubeGroup}/{V1CustomResourceDefinition.KubeApiVersion}",
-                    V1CustomResourceDefinition.KubeKind,
-                    new V1ObjectMeta {Name = $"{entityDefinition.Plural}.{entityDefinition.Group}"});
-
-                var spec = crd.Spec;
-                spec.Group = entityDefinition.Group;
-                spec.Names = new V1CustomResourceDefinitionNames
-                {
-                    Kind = entityDefinition.Kind,
-                    ListKind = entityDefinition.ListKind,
-                    Singular = entityDefinition.Singular,
-                    Plural = entityDefinition.Plural,
-                };
-                spec.Scope = entityDefinition.Scope.ToString();
-
-                var version = new V1CustomResourceDefinitionVersion();
-                spec.Versions = new[] {version};
-
-                // TODO: versions?
-                version.Name = entityDefinition.Version;
-                version.Served = true;
-                version.Storage = true;
-
-                if (entityType.GetProperty("Status") != null)
-                {
-                    version.Subresources = new V1CustomResourceSubresources(null, new { });
-                }
-
-                version.Schema = new V1CustomResourceValidation(MapType(entityType));
-
-                result.Add(crd);
-            }
-
-            return result;
-        }
-
-        private static V1JSONSchemaProps MapProperty(PropertyInfo info)
-        {
-            // TODO: get description somehow.
-            // TODO: support description via XML fields -> but describe how (generate xml file stuff)
-
-            var props = MapType(info.PropertyType);
-            props.Description ??= info.GetCustomAttribute<DisplayAttribute>()?.Description;
-            return props;
-        }
-
-        private static V1JSONSchemaProps MapType(Type type)
-        {
-            var props = new V1JSONSchemaProps();
-
-            // this description is on the class
-            props.Description = type.GetCustomAttributes<DisplayAttribute>(true).FirstOrDefault()?.Description;
-
-            if (type == typeof(V1ObjectMeta))
-            {
-                // TODO(check): is this correct? should metadata be filtered?
-                props.Type = Object;
-            }
-            else if (!IsSimpleType(type))
-            {
-                props.Type = Object;
-                props.Properties = new Dictionary<string, V1JSONSchemaProps>(
-                    type.GetProperties()
-                        .Select(
-                            prop => KeyValuePair.Create(
-                                CamelCase(prop.Name),
-                                MapProperty(prop))));
-            }
-            else if (type == typeof(int) || Nullable.GetUnderlyingType(type) == typeof(int))
-            {
-                props.Type = Integer;
-                props.Format = Int32;
-            }
-            else if (type == typeof(long) || Nullable.GetUnderlyingType(type) == typeof(long))
-            {
-                props.Type = Integer;
-                props.Format = Int64;
-            }
-            else if (type == typeof(float) || Nullable.GetUnderlyingType(type) == typeof(float))
-            {
-                props.Type = Number;
-                props.Format = Float;
-            }
-            else if (type == typeof(double) || Nullable.GetUnderlyingType(type) == typeof(double))
-            {
-                props.Type = Number;
-                props.Format = Double;
-            }
-            else if (type == typeof(string) || Nullable.GetUnderlyingType(type) == typeof(string))
-            {
-                props.Type = String;
-            }
-            else if (type == typeof(bool) || Nullable.GetUnderlyingType(type) == typeof(bool))
-            {
-                props.Type = Boolean;
-            }
-            else if (type == typeof(DateTime) || Nullable.GetUnderlyingType(type) == typeof(DateTime))
-            {
-                props.Type = String;
-                props.Format = DateTime;
-            }
-            else if (type.IsEnum)
-            {
-                props.Type = String;
-                props.EnumProperty = new List<object>(Enum.GetNames(type));
-            }
-
-            if (Nullable.GetUnderlyingType(type) != null)
-            {
-                props.Nullable = true;
-            }
-
-            // TODO: validator attributes
-
-            return props;
+            return GetTypesWithAttribute<KubernetesEntityAttribute>(assembly)
+                .Select(EntityToCrdExtensions.CreateCrd);
         }
 
         private static IEnumerable<Type> GetTypesWithAttribute<TAttribute>(Assembly assembly)
             where TAttribute : Attribute =>
             assembly.GetTypes().Where(type => type.GetCustomAttributes<TAttribute>().Any());
-
-        private static bool IsSimpleType(Type type) =>
-            type.IsPrimitive ||
-            new[]
-            {
-                typeof(string),
-                typeof(decimal),
-                typeof(DateTime),
-                typeof(DateTimeOffset),
-                typeof(TimeSpan),
-                typeof(Guid)
-            }.Contains(type) ||
-            type.IsEnum ||
-            Convert.GetTypeCode(type) != TypeCode.Object ||
-            (type.IsGenericType &&
-             type.GetGenericTypeDefinition() == typeof(Nullable<>) &&
-             IsSimpleType(type.GetGenericArguments()[0]));
-
-        private static string CamelCase(string str) => $"{str.Substring(0, 1).ToLower()}{str.Substring(1)}";
     }
 }

src/KubeOps/Operator/Entities/Annotations/DescriptionAttribute.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace KubeOps.Operator.Entities.Annotations
+{
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Class)]
+    public class DescriptionAttribute : Attribute
+    {
+        public DescriptionAttribute(string description)
+        {
+            Description = description;
+        }
+
+        public string Description { get; }
+    }
+}

src/KubeOps/Operator/Entities/Annotations/ExternalDocsAttribute.cs

@@ -0,0 +1,18 @@
+using System;
+
+namespace KubeOps.Operator.Entities.Annotations
+{
+    [AttributeUsage(AttributeTargets.Property)]
+    public class ExternalDocsAttribute : Attribute
+    {
+        public ExternalDocsAttribute(string url, string? description = null)
+        {
+            Description = description;
+            Url = url;
+        }
+
+        public string? Description { get; }
+
+        public string Url { get; }
+    }
+}

src/KubeOps/Operator/Entities/Annotations/ItemsAttribute.cs

@@ -0,0 +1,14 @@
+using System;
+
+namespace KubeOps.Operator.Entities.Annotations
+{
+    [AttributeUsage(AttributeTargets.Property)]
+    public class ItemsAttribute : Attribute
+    {
+        public long MinItems { get; set; } = -1;
+
+        public long MaxItems { get; set; } = -1;
+
+        public bool UniqueItems { get; set; }
+    }
+}

src/KubeOps/Operator/Entities/Annotations/LengthAttribute.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace KubeOps.Operator.Entities.Annotations
+{
+    [AttributeUsage(AttributeTargets.Property)]
+    public class LengthAttribute : Attribute
+    {
+        public int MinLength { get; set; } = -1;
+
+        public int MaxLength { get; set; } = -1;
+    }
+}

src/KubeOps/Operator/Entities/Annotations/MultipleOfAttribute.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace KubeOps.Operator.Entities.Annotations
+{
+    [AttributeUsage(AttributeTargets.Property)]
+    public class MultipleOfAttribute : Attribute
+    {
+        public MultipleOfAttribute(double value)
+        {
+            Value = value;
+        }
+
+        public double Value { get; }
+    }
+}

src/KubeOps/Operator/Entities/Annotations/PatternAttribute.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace KubeOps.Operator.Entities.Annotations
+{
+    [AttributeUsage(AttributeTargets.Property)]
+    public class PatternAttribute : Attribute
+    {
+        public PatternAttribute(string regexPattern)
+        {
+            RegexPattern = regexPattern;
+        }
+
+        public string RegexPattern { get; }
+    }
+}

src/KubeOps/Operator/Entities/Annotations/RangeMaximum.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace KubeOps.Operator.Entities.Annotations
+{
+    [AttributeUsage(AttributeTargets.Property)]
+    public class RangeMaximumAttribute : Attribute
+    {
+        public double Maximum { get; set; } = -1;
+
+        public bool ExclusiveMaximum { get; set; }
+    }
+}