Refactor container k8s to use plugin resource management.

- Closes #2096.
- Storing resources in a macOS resource bundle won't work
  for unix-layout plugins.
- Rework the kindnet resource fetch to create a plugin
  loader, find the plugin based on the plugin executable
  path, and use the plugin's resourceURL to locate the
  resource.
- Add a findPlugin function to locate the plugin that
  contains a pathname.
- Fix help text to insure example runs regardless of
  the default registry configuration.

Author: jglogan

Makefile

@@ -134,6 +134,7 @@ $(STAGING_DIR):
 	@mkdir -p "$(join $(STAGING_DIR), libexec/container/plugins/machine-apiserver/bin)"
 	@mkdir -p "$(join $(STAGING_DIR), libexec/container/plugins/machine-apiserver/resources)"
 	@mkdir -p "$(join $(STAGING_DIR), libexec/container/plugins/k8s/bin)"
+	@mkdir -p "$(join $(STAGING_DIR), libexec/container/plugins/k8s/resources)"
 
 	@install "$(BUILD_BIN_DIR)/container" "$(join $(STAGING_DIR), bin/container)"
 	@install "$(BUILD_BIN_DIR)/container-apiserver" "$(join $(STAGING_DIR), bin/container-apiserver)"
@@ -149,6 +150,7 @@ $(STAGING_DIR):
 	@install Sources/Plugins/MachineAPIServer/Resources/create-user.sh "$(join $(STAGING_DIR), libexec/container/plugins/machine-apiserver/resources/create-user.sh)"
 	@install "$(BUILD_BIN_DIR)/k8s" "$(join $(STAGING_DIR), libexec/container/plugins/k8s/bin/k8s)"
 	@install Sources/Plugins/K8s/config.toml "$(join $(STAGING_DIR), libexec/container/plugins/k8s/config.toml)"
+	@install Sources/Plugins/K8s/Resources/kindnet.yaml "$(join $(STAGING_DIR), libexec/container/plugins/k8s/resources/kindnet.yaml)"
 
 	@echo Install update script
 	@install scripts/update-container.sh "$(join $(STAGING_DIR), bin/update-container.sh)"

Package.swift

@@ -186,18 +186,18 @@ let package = Package(
                 "ContainerAPIClient",
                 "ContainerLog",
                 "ContainerPersistence",
+                "ContainerPlugin",
                 "ContainerResource",
                 "ContainerVersion",
                 "TerminalProgress",
                 "Yams",
-            ],
-            resources: [.process("Resources/kindnet.yaml")]
+            ]
         ),
         .executableTarget(
             name: "k8s",
             dependencies: ["ContainerK8s"],
             path: "Sources/Plugins/K8s",
-            exclude: ["config.toml"]
+            exclude: ["config.toml", "Resources"]
         ),
         .executableTarget(
             name: "container-apiserver",

Sources/ContainerK8s/K8sHelper.swift

@@ -16,6 +16,7 @@
 
 import ContainerAPIClient
 import ContainerPersistence
+import ContainerPlugin
 import ContainerResource
 import ContainerVersion
 import ContainerizationError
@@ -257,7 +258,7 @@ struct K8sHelper {
             arguments: ["taint", "nodes", "--all", "node-role.kubernetes.io/control-plane-"])
 
         log.info("Applying kindnet CNI", metadata: ["node": "\(nodeID)"])
-        let manifest = try loadKindnetManifest()
+        let manifest = try await loadKindnetManifest(log: log)
         let apply =
             "cat > /tmp/kindnet.yaml <<'EOF'\n\(manifest)\nEOF\n"
             + "\(kubeconfigEnv) kubectl apply -f /tmp/kindnet.yaml"
@@ -269,15 +270,60 @@ struct K8sHelper {
         }
     }
 
-    private static func loadKindnetManifest() throws -> String {
-        guard let url = Bundle.module.url(forResource: "kindnet", withExtension: "yaml"),
-            let contents = try? String(contentsOf: url, encoding: .utf8)
+    private static func loadKindnetManifest(log: Logger) async throws -> String {
+        let pluginLoader = try await makePluginLoader(log: log)
+        guard let plugin = pluginLoader.findPlugin(forExecutable: CommandLine.executablePath),
+            let resourceURL = plugin.resourceURL
         else {
-            throw ContainerizationError(.internalError, message: "kindnet manifest resource missing")
+            throw ContainerizationError(.internalError, message: "unable to locate k8s plugin installation or resources")
+        }
+        let url = resourceURL.appendingPathComponent("kindnet.yaml")
+        guard let contents = try? String(contentsOf: url, encoding: .utf8) else {
+            throw ContainerizationError(.internalError, message: "kindnet manifest resource missing at \(url.path)")
         }
         return contents
     }
 
+    /// NOTE: This duplicates `Application.createPluginLoader()` in
+    /// Sources/ContainerCommands/Application.swift. `ContainerK8s` cannot depend on
+    /// `ContainerCommands`, so the plugin directory/factory list here is kept in sync
+    /// by hand — if that logic changes, update this copy too (or factor a shared
+    /// constructor into `ContainerPlugin`).
+    private static func makePluginLoader(log: Logger) async throws -> PluginLoader {
+        let health = try await ClientHealthCheck.ping(timeout: .seconds(10))
+
+        let installRootPath = FilePath(health.installRoot.path(percentEncoded: false))
+        let userPluginsURL = PluginLoader.userPluginsDir(installRoot: health.installRoot)
+        var directoryExists: ObjCBool = false
+        _ = FileManager.default.fileExists(atPath: userPluginsURL.path, isDirectory: &directoryExists)
+
+        let appBundlePluginsURL = Bundle.main.resourceURL?.appending(path: "plugins")
+        let installRootPluginsPath =
+            installRootPath
+            .appending(FilePath.Component("libexec"))
+            .appending(FilePath.Component("container"))
+            .appending(FilePath.Component("plugins"))
+        let installRootPluginsURL = URL(fileURLWithPath: installRootPluginsPath.string)
+
+        let pluginDirectories = [
+            directoryExists.boolValue ? userPluginsURL : nil,
+            appBundlePluginsURL,
+            installRootPluginsURL,
+        ].compactMap { $0 }
+
+        return try PluginLoader(
+            appRoot: health.appRoot,
+            installRoot: health.installRoot,
+            logRoot: health.logRoot,
+            pluginDirectories: pluginDirectories,
+            pluginFactories: [
+                DefaultPluginFactory(logger: log),
+                AppBundlePluginFactory(logger: log),
+            ],
+            log: log
+        )
+    }
+
     private static let nodePrepScript: String = {
         """
         set -e

Sources/ContainerPlugin/PluginLoader.swift

@@ -15,6 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 import ContainerizationOS
+import Darwin
 import Foundation
 import Logging
 import SystemPackage
@@ -198,6 +199,32 @@ extension PluginLoader {
 
         return nil
     }
+
+    /// Locate the plugin whose executable resolves to `path`, e.g. to let a
+    /// running plugin process identify its own `Plugin` (and thus its
+    /// `resourceURL`) from `CommandLine.executablePath`.
+    public func findPlugin(forExecutable path: FilePath) -> Plugin? {
+        guard let resolvedPath = Self.resolveSymlinks(path.string) else {
+            return nil
+        }
+        for plugin in findPlugins() {
+            guard let binaryPath = Self.resolveSymlinks(plugin.binaryURL.path(percentEncoded: false)) else {
+                continue
+            }
+            if binaryPath == resolvedPath {
+                return plugin
+            }
+        }
+        return nil
+    }
+
+    private static func resolveSymlinks(_ path: String) -> String? {
+        guard let resolved = Darwin.realpath(path, nil) else {
+            return nil
+        }
+        defer { free(resolved) }
+        return String(cString: resolved)
+    }
 }
 
 extension PluginLoader {

Sources/Plugins/K8s/K8sCommand.swift

@@ -39,9 +39,9 @@ public struct K8sCommand: AsyncParsableCommand {
 
               Load a local image into the cluster and run it:
                 $ container image pull docker.io/library/hello-world:latest
-                $ container image tag docker.io/library/hello-world:latest my-hello-world:latest
-                $ container k8s load-image --name my-cluster my-hello-world:latest
-                $ kubectl run hello-job --image=my-hello-world:latest --restart=Never --attach --rm -i
+                $ container image tag docker.io/library/hello-world:latest registry.example.com/max_mustermann/my-hello-world:latest
+                $ container k8s load-image --name my-cluster registry.example.com/max_mustermann/my-hello-world:latest
+                $ kubectl run hello-job --image=registry.example.com/max_mustermann/my-hello-world:latest --image-pull-policy=Never --restart=Never --attach --rm -i
 
               Stop and delete the cluster:
                 $ container k8s delete --name my-cluster

…rces/ContainerK8s/Resources/kindnet.yaml …urces/Plugins/K8s/Resources/kindnet.yamlSources/ContainerK8s/Resources/kindnet.yaml renamed to Sources/Plugins/K8s/Resources/kindnet.yaml Sources/ContainerK8s/Resources/kindnet.yaml renamed to Sources/Plugins/K8s/Resources/kindnet.yaml

@@ -15,6 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 import Foundation
+import SystemPackage
 import Testing
 
 @testable import ContainerPlugin
@@ -88,6 +89,122 @@ struct PluginLoaderTest {
         #expect(loader.findPlugin(name: "throw") == nil)
     }
 
+    @Test
+    func testFindPluginForExecutable() async throws {
+        let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        defer { try? FileManager.default.removeItem(at: tempURL) }
+        let (factory, cliBinaryURL, serviceBinaryURL) = try setupMockWithRealBinaries(tempURL: tempURL)
+        let loader = try PluginLoader(
+            appRoot: tempURL,
+            installRoot: URL(filePath: "/usr/local/"),
+            logRoot: nil,
+            pluginDirectories: [tempURL],
+            pluginFactories: [factory]
+        )
+
+        let cliMatch = loader.findPlugin(forExecutable: FilePath(cliBinaryURL.path(percentEncoded: false)))
+        #expect(cliMatch?.name == "cli")
+
+        let serviceMatch = loader.findPlugin(forExecutable: FilePath(serviceBinaryURL.path(percentEncoded: false)))
+        #expect(serviceMatch?.name == "service")
+    }
+
+    @Test
+    func testFindPluginForExecutableViaSymlinkedInput() async throws {
+        let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        defer { try? FileManager.default.removeItem(at: tempURL) }
+        let (factory, cliBinaryURL, _) = try setupMockWithRealBinaries(tempURL: tempURL)
+        let loader = try PluginLoader(
+            appRoot: tempURL,
+            installRoot: URL(filePath: "/usr/local/"),
+            logRoot: nil,
+            pluginDirectories: [tempURL],
+            pluginFactories: [factory]
+        )
+
+        // Simulate CommandLine.executablePath resolving to a symlink that
+        // ultimately points at the plugin's real binary on disk.
+        let otherTempURL = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        defer { try? FileManager.default.removeItem(at: otherTempURL) }
+        try FileManager.default.createDirectory(at: otherTempURL, withIntermediateDirectories: true)
+        let symlinkURL = otherTempURL.appendingPathComponent("cli-symlink")
+        try FileManager.default.createSymbolicLink(at: symlinkURL, withDestinationURL: cliBinaryURL)
+
+        let match = loader.findPlugin(forExecutable: FilePath(symlinkURL.path(percentEncoded: false)))
+        #expect(match?.name == "cli")
+    }
+
+    @Test
+    func testFindPluginForExecutableWithSymlinkedPluginBinary() async throws {
+        let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        defer { try? FileManager.default.removeItem(at: tempURL) }
+        try FileManager.default.createDirectory(at: tempURL, withIntermediateDirectories: true)
+
+        // The plugin's registered binaryURL is itself a symlink pointing at a
+        // binary that lives elsewhere on disk (e.g. a dev-mode install).
+        let realBinDir = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        defer { try? FileManager.default.removeItem(at: realBinDir) }
+        try FileManager.default.createDirectory(at: realBinDir, withIntermediateDirectories: true)
+        let realBinaryURL = realBinDir.appendingPathComponent("cli-real")
+        try Data().write(to: realBinaryURL)
+
+        let symlinkBinaryURL = tempURL.appendingPathComponent("cli-bin")
+        try FileManager.default.createSymbolicLink(at: symlinkBinaryURL, withDestinationURL: realBinaryURL)
+
+        let cliConfig = PluginConfig(abstract: "cli", author: "CLI", servicesConfig: nil)
+        let cliPlugin = Plugin(binaryURL: symlinkBinaryURL, config: cliConfig)
+        let factory = try MockPluginFactory(tempURL: tempURL, plugins: ["cli": cliPlugin])
+
+        let loader = try PluginLoader(
+            appRoot: tempURL,
+            installRoot: URL(filePath: "/usr/local/"),
+            logRoot: nil,
+            pluginDirectories: [tempURL],
+            pluginFactories: [factory]
+        )
+
+        let match = loader.findPlugin(forExecutable: FilePath(realBinaryURL.path(percentEncoded: false)))
+        #expect(match?.name == "cli")
+    }
+
+    @Test
+    func testFindPluginForExecutableNoMatch() async throws {
+        let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        defer { try? FileManager.default.removeItem(at: tempURL) }
+        let (factory, _, _) = try setupMockWithRealBinaries(tempURL: tempURL)
+        let loader = try PluginLoader(
+            appRoot: tempURL,
+            installRoot: URL(filePath: "/usr/local/"),
+            logRoot: nil,
+            pluginDirectories: [tempURL],
+            pluginFactories: [factory]
+        )
+
+        let unrelatedURL = tempURL.appendingPathComponent("unrelated-bin")
+        try Data().write(to: unrelatedURL)
+
+        let match = loader.findPlugin(forExecutable: FilePath(unrelatedURL.path(percentEncoded: false)))
+        #expect(match == nil)
+    }
+
+    @Test
+    func testFindPluginForExecutableNonexistentPath() async throws {
+        let tempURL = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+        defer { try? FileManager.default.removeItem(at: tempURL) }
+        let (factory, _, _) = try setupMockWithRealBinaries(tempURL: tempURL)
+        let loader = try PluginLoader(
+            appRoot: tempURL,
+            installRoot: URL(filePath: "/usr/local/"),
+            logRoot: nil,
+            pluginDirectories: [tempURL],
+            pluginFactories: [factory]
+        )
+
+        let missingURL = tempURL.appendingPathComponent("does-not-exist")
+        let match = loader.findPlugin(forExecutable: FilePath(missingURL.path(percentEncoded: false)))
+        #expect(match == nil)
+    }
+
     @Test
     func testFilterEnvironmentWithContainerPrefix() async throws {
         let env = [
@@ -289,4 +406,34 @@ struct PluginLoaderTest {
 
         return try MockPluginFactory(tempURL: tempURL, plugins: mockPlugins)
     }
+
+    // Unlike `setupMock`, the plugins here are backed by real, empty files on
+    // disk so `findPlugin(forExecutable:)` can resolve their paths with
+    // `realpath`.
+    private func setupMockWithRealBinaries(tempURL: URL) throws -> (factory: MockPluginFactory, cliBinaryURL: URL, serviceBinaryURL: URL) {
+        try FileManager.default.createDirectory(at: tempURL, withIntermediateDirectories: true)
+        let cliBinaryURL = tempURL.appendingPathComponent("cli-bin")
+        let serviceBinaryURL = tempURL.appendingPathComponent("service-bin")
+        try Data().write(to: cliBinaryURL)
+        try Data().write(to: serviceBinaryURL)
+
+        let cliConfig = PluginConfig(abstract: "cli", author: "CLI", servicesConfig: nil)
+        let cliPlugin: Plugin = Plugin(binaryURL: cliBinaryURL, config: cliConfig)
+        let serviceServicesConfig = PluginConfig.ServicesConfig(
+            loadAtBoot: false,
+            runAtLoad: false,
+            services: [PluginConfig.Service(type: .runtime, description: nil)],
+            defaultArguments: []
+        )
+        let serviceConfig = PluginConfig(abstract: "service", author: "SERVICE", servicesConfig: serviceServicesConfig)
+        let servicePlugin: Plugin = Plugin(binaryURL: serviceBinaryURL, config: serviceConfig)
+        let mockPlugins = [
+            "cli": cliPlugin,
+            MockPluginFactory.throwSuffix: nil,
+            "service": servicePlugin,
+        ]
+
+        let factory = try MockPluginFactory(tempURL: tempURL, plugins: mockPlugins)
+        return (factory, cliBinaryURL, serviceBinaryURL)
+    }
 }