feat: allow to save cluster + token to kubeconf (#23649)

Signed-off-by: Andre Dietisheim <[email protected]>
Assisted by: gemini-cli
Assisted by: cursor
Assisted by: qwen-code

Author: adietish

src/main/kotlin/com/redhat/devtools/gateway/kubeconfig/BlockStyleFilePersister.kt

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2025 Red Hat, Inc.
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *   Red Hat, Inc. - initial API and implementation
+ */
+package com.redhat.devtools.gateway.kubeconfig
+
+import io.kubernetes.client.persister.ConfigPersister
+import org.yaml.snakeyaml.DumperOptions
+import org.yaml.snakeyaml.Yaml
+import java.io.File
+
+class BlockStyleFilePersister(private val file: File) : ConfigPersister {
+
+    @Throws(java.io.IOException::class)
+    override fun save(
+        contexts: ArrayList<Any?>,
+        clusters: ArrayList<Any?>,
+        users: ArrayList<Any?>,
+        preferences: Any?,
+        currentContext: String?
+    ) {
+        val config = mapOf(
+            "apiVersion" to "v1",
+            "kind" to "Config",
+            "current-context" to currentContext,
+            "preferences" to preferences,
+
+            "clusters" to clusters,
+            "contexts" to contexts,
+            "users" to users,
+        )
+
+        synchronized(file) {
+            java.io.FileWriter(file).use { writer ->
+                val options = DumperOptions().apply {
+                    defaultFlowStyle = DumperOptions.FlowStyle.BLOCK
+                    isPrettyFlow = true
+                }
+                val yaml = Yaml(options)
+                yaml.dump(config, writer)
+                writer.flush()
+            }
+        }
+    }
+}

src/main/kotlin/com/redhat/devtools/gateway/kubeconfig/FileWatcher.kt

@@ -18,7 +18,7 @@ import kotlin.io.path.exists
 import kotlin.io.path.isRegularFile
 
 class FileWatcher(
-    private val scope: CoroutineScope = CoroutineScope(SupervisorJob() + Dispatchers.Default),
+    private val scope: CoroutineScope = CoroutineScope(SupervisorJob() + Dispatchers.IO),
     private val dispatcher: CoroutineDispatcher = Dispatchers.IO,
     private val watchService: WatchService = FileSystems.getDefault().newWatchService()
 ) {
@@ -29,23 +29,31 @@ class FileWatcher(
 
     fun start() {
         this.watchJob = scope.launch(dispatcher) {
-            while (isActive) {
-                val key = watchService.poll(100, java.util.concurrent.TimeUnit.MILLISECONDS)
-                if (key == null) {
-                    delay(100)
-                    continue
+            try {
+                while (isActive) {
+                    val key = watchService.poll(100, java.util.concurrent.TimeUnit.MILLISECONDS)
+                    if (key == null) {
+                        delay(100)
+                        continue
+                    }
+                    val dir = registeredKeys[key] ?: continue
+                    pollEvents(key, dir)
+                    key.reset()
                 }
-                val dir = registeredKeys[key] ?: continue
-                pollEvents(key, dir)
-                key.reset()
+            } catch (e: ClosedWatchServiceException) {
+                // Watch service was closed, exit gracefully
             }
         }
     }
 
     fun stop() {
         watchJob?.cancel()
         watchJob = null
-        watchService.close()
+        try {
+            watchService.close()
+        } catch (e: Exception) {
+            // Ignore exceptions when closing
+        }
     }
 
     fun addFile(path: Path): FileWatcher {