Introduce "tart rename" command to rename VMs (#246)

* Introduce "tart rename" command to rename VMs

* Remove unused SystemConfiguration import

* Update Sources/tart/Commands/Rename.swift

Co-authored-by: Pete Goldsmith <peter.n.goldsmith@gmail.com>

Co-authored-by: Pete Goldsmith <peter.n.goldsmith@gmail.com>

Sources/tart/Commands/Rename.swift

@@ -0,0 +1,40 @@
+import ArgumentParser
+import Foundation
+
+struct Rename: AsyncParsableCommand {
+    static var configuration = CommandConfiguration(abstract: "Rename a VM")
+
+    @Argument(help: "VM name")
+    var name: String
+
+    @Argument(help: "new VM name")
+    var newName: String
+
+    func validate() throws {
+        if newName.contains("/") {
+            throw ValidationError("<new-name> should be a local name")
+        }
+    }
+
+    func run() async throws {
+        do {
+            let localStorage = VMStorageLocal()
+
+            if !localStorage.exists(name) {
+                throw ValidationError("failed to rename a non-existent VM: \(name)")
+            }
+
+            if localStorage.exists(newName) {
+                throw ValidationError("failed to rename VM \(name), target VM \(name) already exists, delete it first!")
+            }
+
+            try localStorage.rename(name, newName)
+
+            Foundation.exit(0)
+        } catch {
+            print(error)
+
+            Foundation.exit(1)
+        }
+    }
+}

Sources/tart/Root.swift

@@ -17,6 +17,7 @@ struct Root: AsyncParsableCommand {
       Pull.self,
       Push.self,
       Prune.self,
+      Rename.self,
       Delete.self,
     ])
 

Sources/tart/VMStorageLocal.swift

@@ -32,6 +32,10 @@ class VMStorageLocal {
     _ = try FileManager.default.replaceItemAt(vmURL(name), withItemAt: from.baseURL)
   }
 
+  func rename(_ name: String, _ newName: String) throws {
+    _ = try FileManager.default.replaceItemAt(vmURL(newName), withItemAt: vmURL(name))
+  }
+
   func delete(_ name: String) throws {
     try FileManager.default.removeItem(at: vmURL(name))
   }