feat: able to specify api server flags

core/src/main/java/io/javaoperatorsdk/jenvtest/KubeAPIServerConfig.java

@@ -1,5 +1,6 @@
 package io.javaoperatorsdk.jenvtest;
 
+import java.util.List;
 import java.util.Optional;
 
 public class KubeAPIServerConfig {
@@ -20,10 +21,19 @@ public class KubeAPIServerConfig {
    */
   private final boolean offlineMode;
 
-  KubeAPIServerConfig(String jenvtestDir, String apiServerVersion, boolean offlineMode) {
+  /**
+   * Flags to pass to Kube API Server on startup. Key and value are two separated items, like
+   * specifying min-request-timeout needs to add in order two values: "--min-request-timeout" and
+   * "300" for the actual desired value.
+   */
+  private final List<String> apiServerFlags;
+
+  KubeAPIServerConfig(String jenvtestDir, String apiServerVersion, boolean offlineMode,
+      List<String> apiServerFlags) {
     this.jenvtestDir = jenvtestDir;
     this.apiServerVersion = apiServerVersion;
     this.offlineMode = offlineMode;
+    this.apiServerFlags = apiServerFlags;
   }
 
   public String getJenvtestDir() {
@@ -37,4 +47,8 @@ public Optional<String> getApiServerVersion() {
   public boolean isOfflineMode() {
     return offlineMode;
   }
+
+  public List<String> getApiServerFlags() {
+    return apiServerFlags;
+  }
 }

core/src/main/java/io/javaoperatorsdk/jenvtest/KubeAPIServerConfigBuilder.java

@@ -1,6 +1,8 @@
 package io.javaoperatorsdk.jenvtest;
 
 import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
 
 public final class KubeAPIServerConfigBuilder {
 
@@ -13,6 +15,7 @@ public final class KubeAPIServerConfigBuilder {
   private String jenvtestDir;
   private String apiServerVersion;
   private Boolean offlineMode;
+  private final List<String> apiServerFlags = new ArrayList<>(0);
 
   public KubeAPIServerConfigBuilder() {}
 
@@ -58,6 +61,28 @@ public KubeAPIServerConfig build() {
         this.apiServerVersion = apiServerVersionEnvVar;
       }
     }
-    return new KubeAPIServerConfig(jenvtestDir, apiServerVersion, offlineMode);
+    return new KubeAPIServerConfig(jenvtestDir, apiServerVersion, offlineMode, apiServerFlags);
+  }
+
+  public void withApiServerFlags(List<String> flags) {
+    apiServerFlags.addAll(flags);
+  }
+
+  public void withApiServerFlag(String key, String value) {
+    checkKeyPrefix(key);
+    apiServerFlags.add(key);
+    apiServerFlags.add(value);
+  }
+
+  public void withApiServerFlag(String key) {
+    checkKeyPrefix(key);
+    apiServerFlags.add(key);
+  }
+
+  private void checkKeyPrefix(String key) {
+    if (!key.startsWith("--")) {
+      throw new JenvtestException(
+          "Kube API Server flag needs to start with double dash: '--'; Instead found key: " + key);
+    }
   }
 }

core/src/main/java/io/javaoperatorsdk/jenvtest/process/KubeAPIServerProcess.java

@@ -1,6 +1,9 @@
 package io.javaoperatorsdk.jenvtest.process;
 
+import java.io.File;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Scanner;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -39,21 +42,9 @@ public int startApiServer(int etcdPort) {
         throw new JenvtestException(
             "Missing binary for API Server on path: " + apiServerBinary.getAbsolutePath());
       }
-      var port = Utils.findFreePort();
-      apiServerProcess = new ProcessBuilder(apiServerBinary.getAbsolutePath(),
-          "--cert-dir", config.getJenvtestDir(),
-          "--secure-port", "" + port,
-          "--etcd-servers", "http://0.0.0.0:" + etcdPort,
-          "--authorization-mode", "RBAC",
-          "--service-account-issuer", "https://localhost",
-          "--service-account-signing-key-file", certManager.getAPIServerKeyPath(),
-          "--service-account-signing-key-file", certManager.getAPIServerKeyPath(),
-          "--service-account-key-file", certManager.getAPIServerKeyPath(),
-          "--service-account-issuer", certManager.getAPIServerCertPath(),
-          "--disable-admission-plugins", "ServiceAccount",
-          "--client-ca-file", certManager.getClientCertPath(),
-          "--service-cluster-ip-range", "10.0.0.0/24",
-          "--allow-privileged")
+      var apiServerPort = Utils.findFreePort();
+      var command = createCommand(apiServerBinary, apiServerPort, etcdPort);
+      apiServerProcess = new ProcessBuilder(command)
           .start();
       Utils.redirectProcessOutputToLogger(apiServerProcess.getInputStream(), apiLog);
       Utils.redirectProcessOutputToLogger(apiServerProcess.getErrorStream(), apiLog);
@@ -66,12 +57,32 @@ public int startApiServer(int etcdPort) {
         return null;
       });
       log.debug("API Server started");
-      return port;
+      return apiServerPort;
     } catch (IOException e) {
       throw new JenvtestException(e);
     }
   }
 
+  private List<String> createCommand(File apiServerBinary, int apiServerPort, int etcdPort) {
+    var command = new ArrayList<String>();
+    command.add(apiServerBinary.getAbsolutePath());
+    command.addAll(config.getApiServerFlags());
+    command.addAll(List.of("--cert-dir", config.getJenvtestDir(),
+        "--secure-port", "" + apiServerPort,
+        "--etcd-servers", "http://0.0.0.0:" + etcdPort,
+        "--authorization-mode", "RBAC",
+        "--service-account-issuer", "https://localhost",
+        "--service-account-signing-key-file", certManager.getAPIServerKeyPath(),
+        "--service-account-signing-key-file", certManager.getAPIServerKeyPath(),
+        "--service-account-key-file", certManager.getAPIServerKeyPath(),
+        "--service-account-issuer", certManager.getAPIServerCertPath(),
+        "--disable-admission-plugins", "ServiceAccount",
+        "--client-ca-file", certManager.getClientCertPath(),
+        "--service-cluster-ip-range", "10.0.0.0/24",
+        "--allow-privileged"));
+    return command;
+  }
+
   public void waitUntilDefaultNamespaceCreated() {
     try {
       AtomicBoolean started = new AtomicBoolean(false);