From f20a98bf01829676b9c91969766b4733b7bdd4ad Mon Sep 17 00:00:00 2001
From: Fedor Korotkov <fedor.korotkov@gmail.com>
Date: Fri, 6 May 2022 13:38:56 -0400
Subject: [PATCH] Smart generation of new MAC addresses (#45)

* Introduce --new-mac-address flag for Clone command

Related to https://github.com/cirruslabs/tart/issues/20#issuecomment-1116732505

* Smart generation of new MAC addresses
---
 Sources/tart/Commands/Clone.swift | 31 +++++++++++++++++++++++++------
 Sources/tart/VMDirectory.swift    |  6 ++++--
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/Sources/tart/Commands/Clone.swift b/Sources/tart/Commands/Clone.swift
index d228662..a175703 100644
--- a/Sources/tart/Commands/Clone.swift
+++ b/Sources/tart/Commands/Clone.swift
@@ -13,13 +13,21 @@ struct Clone: AsyncParsableCommand {
 
   func run() async throws {
     do {
-      // Pull the VM in case it's OCI-based and doesn't exist locally yet
-      if let remoteName = try? RemoteName(sourceName), !VMStorageOCI().exists(remoteName) {
-        let registry = try Registry(host: remoteName.host, namespace: remoteName.namespace)
-        try await VMStorageOCI().pull(remoteName, registry: registry)
-      }
+      if let remoteName = try? RemoteName(sourceName) {
+        if !VMStorageOCI().exists(remoteName) {
+          // Pull the VM in case it's OCI-based and doesn't exist locally yet
+          let registry = try Registry(host: remoteName.host, namespace: remoteName.namespace)
+          try await VMStorageOCI().pull(remoteName, registry: registry)
+        }
+        let removeVM = try VMStorageHelper.open(sourceName)
 
-      try VMStorageHelper.open(sourceName).clone(to: VMStorageLocal().create(newName))
+        let removeConfig = try VMConfig.init(fromURL: removeVM.configURL)
+        let needToGenerateNewMAC = try localVMExistsWith(macAddress: removeConfig.macAddress.string)
+
+        try removeVM.clone(to: VMStorageLocal().create(newName), generateMAC: needToGenerateNewMAC)
+      } else {
+        try VMStorageHelper.open(sourceName).clone(to: VMStorageLocal().create(newName), generateMAC: true)
+      }
 
       Foundation.exit(0)
     } catch {
@@ -28,4 +36,15 @@ struct Clone: AsyncParsableCommand {
       Foundation.exit(1)
     }
   }
+
+  private func localVMExistsWith(macAddress: String) throws -> Bool {
+    var needToGenerateNewMAC = false
+    for (_, localDir) in try VMStorageLocal().list() {
+      let localConfig = try VMConfig.init(fromURL: localDir.configURL)
+      if localConfig.macAddress.string == macAddress {
+        needToGenerateNewMAC = true
+      }
+    }
+    return needToGenerateNewMAC
+  }
 }
diff --git a/Sources/tart/VMDirectory.swift b/Sources/tart/VMDirectory.swift
index a675e0b..492eda3 100644
--- a/Sources/tart/VMDirectory.swift
+++ b/Sources/tart/VMDirectory.swift
@@ -48,14 +48,16 @@ struct VMDirectory {
     }
   }
 
-  func clone(to: VMDirectory) throws {
+  func clone(to: VMDirectory, generateMAC: Bool) throws {
     try FileManager.default.copyItem(at: configURL, to: to.configURL)
     try FileManager.default.copyItem(at: nvramURL, to: to.nvramURL)
     try FileManager.default.copyItem(at: diskURL, to: to.diskURL)
 
     // Re-generate MAC address
     var newVMConfig = try VMConfig(fromURL: to.configURL)
-    newVMConfig.macAddress = VZMACAddress.randomLocallyAdministered()
+    if generateMAC {
+      newVMConfig.macAddress = VZMACAddress.randomLocallyAdministered()
+    }
     try newVMConfig.save(toURL: to.configURL)
   }