feat(storage): choose where the container runtime keeps its data

Sources/AppleDockerApp/AppState.swift

@@ -75,6 +75,10 @@ final class AppState {
     var diskUsage = SystemDiskUsage()
     /// Whether a cleanup operation is in flight (disables the cleanup buttons).
     var isCleaning = false
+    /// Whether the runtime store is being moved.
+    var isMovingStorage = false
+    /// Progress or result of the last storage move, shown in Settings > Storage.
+    var storageMessage: String?
     /// Whether a CLI install is in flight.
     var isInstalling = false
     /// Whether an app install into /Applications is in flight.
@@ -692,6 +696,63 @@ final class AppState {
         }
     }
 
+    /// Moves the runtime store into `parent`. The daemon is stopped for the copy
+    /// and started again on the new location. If the move fails, the daemon is
+    /// started on the original location; if the start fails after the move, the
+    /// original is restored.
+    func moveStorage(toParent parent: URL) async {
+        guard !isMovingStorage else { return }
+        isMovingStorage = true
+        defer { isMovingStorage = false }
+        let opID = beginOperation("moveStorage", section: .settings)
+        defer { endOperation(opID) }
+
+        let location = StorageLocation.standard
+        storageMessage = "Stopping the runtime…"
+        do {
+            try await service.daemon.stop()
+            storageMessage = "Copying the storage to \(parent.path)…"
+            let result: StorageMoveResult
+            do {
+                // The copy can take minutes; keep it off the main thread so the window stays responsive.
+                result = try await Task.detached(priority: .userInitiated) {
+                    try location.move(toParent: parent)
+                }.value
+            } catch {
+                try? await service.daemon.start()
+                throw error
+            }
+            storageMessage = "Starting the runtime on the new location…"
+            do {
+                try await service.daemon.start(environment: [StorageLocation.environmentName: result.newRoot.path])
+            } catch {
+                // Back to the original: put it back, drop the unused copy, and
+                // start the daemon on the original location.
+                try? location.restoreBackup()
+                try? FileManager.default.removeItem(at: result.newRoot)
+                try? await service.daemon.start()
+                throw error
+            }
+            reconnect()
+            await refresh()
+            errorMessage = nil
+            storageMessage = "Storage moved to \(result.newRoot.path). The original is kept as a backup."
+        } catch {
+            storageMessage = "Move failed: \(error.localizedDescription)"
+            errorMessage = error.localizedDescription
+        }
+    }
+
+    /// Deletes the backup left by `moveStorage`, once the moved store is in use.
+    func deleteStorageBackup() {
+        do {
+            try StorageLocation.standard.deleteBackup()
+            errorMessage = nil
+        } catch {
+            errorMessage = error.localizedDescription
+        }
+    }
+
     /// Delete the buildkit builder container (frees the build cache).
     func deleteBuildkitBuilder() async {
         let opID = beginOperation("deleteBuildkitBuilder", section: .images)

Sources/AppleDockerApp/Views/SettingsView.swift

@@ -3,6 +3,7 @@
 //===----------------------------------------------------------------------===//
 
 import SwiftUI
+import AppKit
 import ServiceManagement
 import ContainerBackend
 
@@ -21,6 +22,11 @@ struct SettingsView: View {
     @State private var confirmFull = false
     @State private var confirmInstall = false
     @State private var confirmInstallApp = false
+    @State private var storageSizes: [(name: String, bytes: UInt64)] = []
+    @State private var storageRedirected = false
+    @State private var storageHasBackup = false
+    @State private var pendingStorageParent: URL?
+    @State private var confirmDeleteBackup = false
     @State private var confirmRuntimeUpgrade = false
 
     var body: some View {
@@ -293,9 +299,126 @@ struct SettingsView: View {
         }
     }
 
+    /// Where the runtime keeps its data, with a move action.
+    private var storageLocation: some View {
+        Section("Location") {
+            HStack {
+                Text("Current")
+                Spacer()
+                Text(StorageLocation.standard.resolvedRoot.path)
+                    .foregroundStyle(.secondary)
+                    .lineLimit(1)
+                    .truncationMode(.middle)
+            }
+            if storageRedirected {
+                Text("This folder is a link to another disk.")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+            }
+            ForEach(storageSizes, id: \.name) { folder in
+                HStack {
+                    Text(folder.name)
+                        .foregroundStyle(.secondary)
+                    Spacer()
+                    Text(Self.formatBytes(folder.bytes))
+                        .foregroundStyle(.secondary)
+                }
+                .font(.caption)
+            }
+            if storageHasBackup {
+                HStack {
+                    Text("The original data is kept as a backup until you delete it.")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                    Spacer()
+                    Button("Delete backup…", role: .destructive) {
+                        confirmDeleteBackup = true
+                    }
+                    .disabled(state.isMovingStorage)
+                }
+            }
+            HStack {
+                Button("Move storage…") {
+                    chooseStorageFolder()
+                }
+                .disabled(state.isMovingStorage)
+                if state.isMovingStorage {
+                    ProgressView()
+                        .controlSize(.small)
+                }
+            }
+            if let message = state.storageMessage {
+                Text(message)
+                    .font(.caption)
+                    .foregroundStyle(message.hasPrefix("Move failed") ? .red : .secondary)
+                    .fixedSize(horizontal: false, vertical: true)
+            }
+        }
+        .onAppear(perform: reloadStorageInfo)
+        .onChange(of: state.isMovingStorage) { _, moving in
+            if !moving { reloadStorageInfo() }
+        }
+        .confirmationDialog(
+            "Move the container storage?",
+            isPresented: Binding(
+                get: { pendingStorageParent != nil },
+                set: { if !$0 { pendingStorageParent = nil } }
+            ),
+            titleVisibility: .visible
+        ) {
+            Button("Move storage") {
+                guard let parent = pendingStorageParent else { return }
+                pendingStorageParent = nil
+                Task { @MainActor in
+                    await state.moveStorage(toParent: parent)
+                }
+            }
+            Button("Cancel", role: .cancel) {
+                pendingStorageParent = nil
+            }
+        } message: {
+            Text("Images, containers, volumes and the build cache are copied to \(pendingStorageParent?.path ?? "the chosen folder"). Running containers are stopped during the move. The original stays as a backup until you delete it.")
+        }
+        .confirmationDialog(
+            "Delete the backup?",
+            isPresented: $confirmDeleteBackup,
+            titleVisibility: .visible
+        ) {
+            Button("Delete backup", role: .destructive) {
+                state.deleteStorageBackup()
+                reloadStorageInfo()
+            }
+            Button("Cancel", role: .cancel) {}
+        } message: {
+            Text("Only do this after checking that images and containers work from the new location.")
+        }
+    }
+
+    private func reloadStorageInfo() {
+        let location = StorageLocation.standard
+        storageRedirected = location.isRedirected
+        storageHasBackup = location.backup != nil
+        storageSizes = location.sizes()
+    }
+
+    /// Lets the user pick a parent folder, then asks for confirmation.
+    private func chooseStorageFolder() {
+        let panel = NSOpenPanel()
+        panel.canChooseFiles = false
+        panel.canChooseDirectories = true
+        panel.canCreateDirectories = true
+        panel.allowsMultipleSelection = false
+        panel.prompt = "Choose"
+        panel.message = "Choose the folder where the container storage should live."
+        if panel.runModal() == .OK, let url = panel.url {
+            pendingStorageParent = url
+        }
+    }
+
     private var storage: some View {
         ScrollView {
             Form {
+            storageLocation
             Section("Disk usage") {
                 HStack {
                     Text("Total")

Sources/ContainerBackend/LaunchdManager.swift

@@ -24,9 +24,10 @@ public struct LaunchdManager: Sendable {
     }
 
     /// Start the container services. Idempotent: starting an already-running
-    /// daemon is a no-op.
-    public func start() async throws {
-        let result = try await runner.run(["system", "start"])
+    /// daemon is a no-op. `environment` is passed to `container system start`,
+    /// which records it for the daemon (for example CONTAINER_APP_ROOT).
+    public func start(environment: [String: String] = [:]) async throws {
+        let result = try await runner.run(["system", "start"], environment: environment)
         guard result.succeeded else {
             throw BackendError.operationFailed(
                 "failed to start container services: \(result.stderr.trimmingCharacters(in: .whitespacesAndNewlines))"