feat(crd-generator): process generated CRDs before they are written out (6828)

feat: process generated CRDs but before they are written out

Fixes #6827
---
refactor: unify handling of post-processor with rest of configuration

Author: metacosm

CHANGELOG.md

@@ -14,6 +14,8 @@
 
 #### New Features
 
+* Fix #6827: Add CRDPostProcessor to process generated CRDs before they are written out
+
 #### _**Note**_: Breaking changes
 
 ### 7.1.0 (2025-01-30)

crd-generator/api-v2/src/main/java/io/fabric8/crdv2/generator/CRDGenerator.java

@@ -48,6 +48,8 @@
 public class CRDGenerator {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(CRDGenerator.class);
+  private static final CRDPostProcessor nullProcessor = new CRDPostProcessor() {
+  };
   private final Map<String, AbstractCustomResourceHandler> handlers = new HashMap<>(2);
   private CRDOutput<? extends OutputStream> output;
   private boolean parallel;
@@ -56,10 +58,10 @@ public class CRDGenerator {
   private KubernetesSerialization kubernetesSerialization;
   private Map<String, CustomResourceInfo> infos;
   private boolean minQuotes = false;
+  private CRDPostProcessor postProcessor = nullProcessor;
 
   public CRDGenerator inOutputDir(File outputDir) {
-    output = new DirCRDOutput(outputDir);
-    return this;
+    return withOutput(new DirCRDOutput(outputDir));
   }
 
   public CRDGenerator withOutput(CRDOutput<? extends OutputStream> output) {
@@ -88,6 +90,11 @@ public CRDGenerator withObjectMapper(ObjectMapper mapper, KubernetesSerializatio
     return this;
   }
 
+  public CRDGenerator withPostProcessor(CRDPostProcessor postProcessor) {
+    this.postProcessor = postProcessor;
+    return this;
+  }
+
   public CRDGenerator forCRDVersions(List<String> versions) {
     return versions != null && !versions.isEmpty() ? forCRDVersions(versions.toArray(new String[0]))
         : this;
@@ -115,9 +122,7 @@ Map<String, AbstractCustomResourceHandler> getHandlers() {
     return handlers;
   }
 
-  // this is public API, so we cannot change the signature, so there is no way to prevent the possible heap pollution
-  // (we also cannot use @SafeVarargs, because that requires the method to be final, which is another signature change)
-  @SuppressWarnings("unchecked")
+  @SafeVarargs
   public final CRDGenerator customResourceClasses(Class<? extends HasMetadata>... crClasses) {
     if (crClasses == null) {
       return this;
@@ -163,6 +168,12 @@ public int generate() {
     return detailedGenerate().numberOfGeneratedCRDs();
   }
 
+  /**
+   * Generates the CRDs with the provided configuration and returns detailed information about what was generated as a
+   * {@link CRDGenerationInfo} instance.
+   *
+   * @return a {@link CRDGenerationInfo} providing detailed information about what was generated
+   */
   public CRDGenerationInfo detailedGenerate() {
     if (getCustomResourceInfos().isEmpty()) {
       LOGGER.warn("No resources were registered with the 'customResources' method to be generated");
@@ -201,9 +212,10 @@ public CRDGenerationInfo detailedGenerate() {
 
         if (parallel) {
           handlers.values().stream().map(h -> ForkJoinPool.commonPool().submit(() -> h.handle(info, context.forkContext())))
-              .collect(Collectors.toList()).stream().forEach(ForkJoinTask::join);
+              .collect(Collectors.toList())
+              .forEach(ForkJoinTask::join);
         } else {
-          handlers.values().stream().forEach(h -> h.handle(info, context.forkContext()));
+          handlers.values().forEach(h -> h.handle(info, context.forkContext()));
         }
       }
     }
@@ -217,6 +229,10 @@ public CRDGenerationInfo detailedGenerate() {
   public void emitCrd(HasMetadata crd, Set<String> dependentClassNames, CRDGenerationInfo crdGenerationInfo) {
     final String version = ApiVersionUtil.trimVersion(crd.getApiVersion());
     final String crdName = crd.getMetadata().getName();
+
+    // post-process the CRD if needed
+    crd = postProcessor.process(crd, version);
+
     try {
       final String outputName = getOutputName(crdName, version);
       try (final OutputStreamWriter writer = new OutputStreamWriter(output.outputFor(outputName), StandardCharsets.UTF_8)) {

crd-generator/api-v2/src/main/java/io/fabric8/crdv2/generator/CRDPostProcessor.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2015 Red Hat, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *         http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.fabric8.crdv2.generator;
+
+import io.fabric8.kubernetes.api.model.HasMetadata;
+
+public interface CRDPostProcessor {
+
+  /**
+   * Processes the specified CRD (passed as {@link HasMetadata} to be able to handle multiple versions of the CRD spec) after
+   * they are generated but before they are written out
+   *
+   * @param crd the CRD to process as a {@link HasMetadata}
+   * @param crdSpecVersion the CRD specification version of the CRD to process (to be able to cast to the appropriate CRD class)
+   * @return the modified CRD (though, typically, this would just be the CRD specified as input, modified in place)
+   */
+  default HasMetadata process(HasMetadata crd, String crdSpecVersion) {
+    return crd;
+  }
+}

crd-generator/api-v2/src/test/java/io/fabric8/crdv2/generator/CRDGeneratorTest.java

@@ -38,6 +38,7 @@
 import io.fabric8.kubernetes.api.model.apiextensions.v1.CustomResourceValidation;
 import io.fabric8.kubernetes.api.model.apiextensions.v1.JSONSchemaProps;
 import io.fabric8.kubernetes.client.CustomResource;
+import io.fabric8.kubernetes.client.utils.KubernetesSerialization;
 import io.fabric8.kubernetes.client.utils.Serialization;
 import io.fabric8.kubernetes.model.Scope;
 import org.junit.jupiter.api.RepeatedTest;
@@ -49,6 +50,7 @@
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
+import java.io.FileInputStream;
 import java.net.URL;
 import java.nio.file.Files;
 import java.util.ArrayList;
@@ -595,6 +597,38 @@ void checkK8sValidationRules() throws Exception {
     assertTrue(outputDir.delete());
   }
 
+  @Test
+  void checkPostProcessing() throws Exception {
+    // generated CRD
+    final File outputDir = Files.createTempDirectory("crd-").toFile();
+    final String crdName = CustomResourceInfo.fromClass(Simplest.class).crdName();
+
+    final CRDGenerationInfo crdInfo = newCRDGenerator()
+        .inOutputDir(outputDir)
+        .customResourceClasses(Simplest.class)
+        .forCRDVersions("v1")
+        .withPostProcessor(new CRDPostProcessor() {
+          @Override
+          public HasMetadata process(HasMetadata crd, String crdSpecVersion) {
+            final var meta = crd.getMetadata().edit().addToLabels("foo", "bar").build();
+            crd.setMetadata(meta);
+            return crd;
+          }
+        })
+        .detailedGenerate();
+
+    final File crdFile = new File(crdInfo.getCRDInfos(crdName).get("v1").getFilePath());
+    final var serialization = new KubernetesSerialization();
+    final var crd = serialization.unmarshal(new FileInputStream(crdFile), HasMetadata.class);
+    assertNotNull(crd);
+    assertEquals(crdName, crd.getMetadata().getName());
+    assertEquals("bar", crd.getMetadata().getLabels().get("foo"));
+
+    // only delete the generated files if the test is successful
+    assertTrue(crdFile.delete());
+    assertTrue(outputDir.delete());
+  }
+
   private CustomResourceDefinitionVersion checkCRD(Class<? extends CustomResource<?, ?>> customResource, String kind,
       String plural,
       Scope scope) {

doc/CRD-generator-migration-v2.md

@@ -16,7 +16,8 @@ _Deprecated since 7.0.0_
 _GA since 7.0.0_
 
 - **CRD Generator API v2** - `io.fabric8:crd-generator-api-v2`  
-  _Core implementation of the new generator, based on [Jackson/jsonSchema](https://github.com/FasterXML/jackson-module-jsonSchema)._
+  _Core implementation of the new generator, based
+  on [Jackson/jsonSchema](https://github.com/FasterXML/jackson-module-jsonSchema)._
 - **CRD Generator Collector** - `io.fabric8:crd-generator-collector`  
   _Shared component to find and load compiled Custom Resource classes in directories and Jar files._
 - **CRD Generator Maven Plugin** - `io.fabric8:crd-generator-maven-plugin`   
@@ -101,7 +102,12 @@ myMap:
 
 ## Default values for CRD fields can be numeric or boolean
 
-Previously default values defined by `@Default` could only be used on string fields. 
+Previously default values defined by `@Default` could only be used on string fields.
 With CRD Generator v2 defaults can be set on numeric and boolean fields, too.
 In the same way is `@JsonProperty(defaultValue)` now working.
 
+## Post-processing CRDs before they are written out to disk
+
+It is now possible to provide a `CRDPostProcessor` implementation when generating CRDs via the
+`CRDGenerator.detailedGenerate` method. This allows to process generated CRDs before they are written out to the disk.
+

junit/kube-api-test/core/src/test/java/io/fabric8/kubeapitest/binary/BinaryDownloaderTest.java

@@ -34,19 +34,19 @@ class BinaryDownloaderTest {
   BinaryDownloader binaryDownloader = new BinaryDownloader("target", mockBinaryRepo, mockOsInfo);
 
   @Test
-    void findsLatestBinary() {
-        when(mockOsInfo.getOSName()).thenReturn("linux");
-        when(mockOsInfo.getOSArch()).thenReturn("amd64");
+  void findsLatestBinary() {
+    when(mockOsInfo.getOSName()).thenReturn("linux");
+    when(mockOsInfo.getOSArch()).thenReturn("amd64");
 
-        when(mockBinaryRepo.listObjectNames()).thenReturn(List.of(
-                        new ArchiveDescriptor("1.17.9","amd64","linux"),
-            new ArchiveDescriptor("1.26.1","amd64","darwin"),
-            new ArchiveDescriptor(VERSION,"amd64","linux"))
-                .stream());
+    when(mockBinaryRepo.listObjectNames()).thenReturn(List.of(
+        new ArchiveDescriptor("1.17.9", "amd64", "linux"),
+        new ArchiveDescriptor("1.26.1", "amd64", "darwin"),
+        new ArchiveDescriptor(VERSION, "amd64", "linux"))
+        .stream());
 
-        var latest = binaryDownloader.findLatestVersion();
+    var latest = binaryDownloader.findLatestVersion();
 
-        assertThat(latest).isEqualTo(VERSION);
-    }
+    assertThat(latest).isEqualTo(VERSION);
+  }
 
 }

junit/kube-api-test/core/src/test/java/io/fabric8/kubeapitest/kubeconfig/KubeConfigTest.java

@@ -33,18 +33,18 @@ class KubeConfigTest {
   KubeConfig kubeConfig = new KubeConfig(certManagerMock, null);
 
   @Test
-    void generatesConfigYaml() {
-        when(certManagerMock.getAPIServerCertPath()).thenReturn(API_CERT_PATH);
-        when(certManagerMock.getClientCertPath()).thenReturn(CLIENT_KEY_PATH);
-        when(certManagerMock.getClientKeyPath()).thenReturn(CLIENT_CERT_PATH);
-
-        String yaml = kubeConfig.generateKubeConfigYaml(API_SERVER_PORT);
-
-        assertThat(yaml)
-                .contains(""+API_SERVER_PORT)
-                .contains(API_CERT_PATH)
-                .contains(CLIENT_CERT_PATH)
-                .contains(CLIENT_KEY_PATH);
-    }
+  void generatesConfigYaml() {
+    when(certManagerMock.getAPIServerCertPath()).thenReturn(API_CERT_PATH);
+    when(certManagerMock.getClientCertPath()).thenReturn(CLIENT_KEY_PATH);
+    when(certManagerMock.getClientKeyPath()).thenReturn(CLIENT_CERT_PATH);
+
+    String yaml = kubeConfig.generateKubeConfigYaml(API_SERVER_PORT);
+
+    assertThat(yaml)
+        .contains("" + API_SERVER_PORT)
+        .contains(API_CERT_PATH)
+        .contains(CLIENT_CERT_PATH)
+        .contains(CLIENT_KEY_PATH);
+  }
 
 }