tart {clone,pull}: make deduplication opt-in (#924)

* Document automatic pruning in FAQ

* tart {pull,clone}: consistent automatic pruning documentation in --help

.ci/set-version.sh

@@ -3,3 +3,5 @@
 TMPFILE=$(mktemp)
 envsubst < Sources/tart/CI/CI.swift > $TMPFILE
 mv $TMPFILE Sources/tart/CI/CI.swift
+
+/usr/libexec/PlistBuddy -c "Add :CFBundleShortVersionString string ${CIRRUS_TAG}" Info.plist

Package.resolved

@@ -1,13 +1,13 @@
 {
-  "originHash" : "2c514a4a1d7e106713db744bee89edb40d75da63e6611990ec2f4b0da53c0455",
+  "originHash" : "6a15657d8cb1d3e2b447f31aff5b47d6a9655d2262e48ca76476ba525435269b",
   "pins" : [
     {
       "identity" : "antlr4",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/antlr/antlr4",
       "state" : {
-        "branch" : "dev",
+        "revision" : "cc82115a4e7f53d71d9d905caa2c2dfa4da58899",
-        "revision" : "2703a8516c0fb7fe92db6b9c40e0113f577646d2"
+        "version" : "4.13.2"
       }
     },
     {
@@ -24,8 +24,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/groue/Semaphore",
       "state" : {
-        "revision" : "f1c4a0acabeb591068dea6cffdd39660b86dec28",
+        "revision" : "2543679282aa6f6c8ecf2138acd613ed20790bc2",
-        "version" : "0.0.8"
+        "version" : "0.1.0"
       }
     },
     {
@@ -33,8 +33,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/getsentry/sentry-cocoa",
       "state" : {
-        "revision" : "ef4fec9dfb8dd5027b09a4a5c9362feafd118e1a",
+        "revision" : "5575af93efb776414f243e93d6af9f6258dc539a",
-        "version" : "8.24.0"
+        "version" : "8.36.0"
       }
     },
     {
@@ -51,8 +51,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-argument-parser",
       "state" : {
-        "revision" : "46989693916f56d1186bd59ac15124caef896560",
+        "revision" : "41982a3656a71c768319979febd796c6fd111d5c",
-        "version" : "1.3.1"
+        "version" : "1.5.0"
       }
     },
     {
@@ -61,7 +61,7 @@
       "location" : "https://github.com/apple/swift-async-algorithms",
       "state" : {
         "branch" : "main",
-        "revision" : "f05e450f0b909c0e80670a47516c4b9700b9e5da"
+        "revision" : "5c8bd186f48c16af0775972700626f0b74588278"
       }
     },
     {
@@ -78,8 +78,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-collections.git",
       "state" : {
-        "revision" : "f504716c27d2e5d4144fa4794b12129301d17729",
+        "revision" : "9bf03ff58ce34478e66aaee630e491823326fd06",
-        "version" : "1.0.3"
+        "version" : "1.1.3"
       }
     },
     {
@@ -87,8 +87,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-log.git",
       "state" : {
-        "revision" : "e97a6fcb1ab07462881ac165fdbb37f067e205d5",
+        "revision" : "9cb486020ebf03bfa5b5df985387a14a98744537",
-        "version" : "1.5.4"
+        "version" : "1.6.1"
       }
     },
     {
@@ -105,8 +105,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/fumoboy007/swift-retry",
       "state" : {
-        "revision" : "9f133487ffc2ab4539688c29efe57bb1ba31d7b0",
+        "revision" : "df9d7b185d2e433147ec0083a73c257e665eea0d",
-        "version" : "0.2.3"
+        "version" : "0.2.4"
       }
     },
     {
@@ -141,8 +141,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/nicklockwood/SwiftFormat",
       "state" : {
-        "revision" : "9df3b01f477163b33d5e63c5e2e5b9f946a49c56",
+        "revision" : "ab6844edb79a7b88dc6320e6cee0a0db7674dac3",
-        "version" : "0.53.6"
+        "version" : "0.54.5"
       }
     },
     {

Package.swift

@@ -15,10 +15,10 @@ let package = Package(
     .package(url: "https://github.com/apple/swift-algorithms", from: "1.2.0"),
     .package(url: "https://github.com/apple/swift-async-algorithms", branch: "main"),
     .package(url: "https://github.com/malcommac/SwiftDate", from: "7.0.0"),
-    .package(url: "https://github.com/antlr/antlr4", branch: "dev"),
+    .package(url: "https://github.com/antlr/antlr4", exact: "4.13.2"),
     .package(url: "https://github.com/apple/swift-atomics.git", .upToNextMajor(from: "1.2.0")),
     .package(url: "https://github.com/nicklockwood/SwiftFormat", from: "0.53.6"),
-    .package(url: "https://github.com/getsentry/sentry-cocoa", from: "8.24.0"),
+    .package(url: "https://github.com/getsentry/sentry-cocoa", from: "8.36.0"),
     .package(url: "https://github.com/cfilipov/TextTable", branch: "master"),
     .package(url: "https://github.com/sersoft-gmbh/swift-sysctl.git", from: "1.8.0"),
     .package(url: "https://github.com/orchetect/SwiftRadix", from: "1.3.1"),

Resources/Info.plist

@@ -2,22 +2,24 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
-    <key>CFBundleName</key>
+	<key>CFBundleName</key>
-    <string>tart</string>
+	<string>Tart</string>
-    <key>CFBundleIdentifier</key>
+	<key>CFBundleDisplayName</key>
-    <string>org.cirruslabs.tart</string>
+	<string>Tart</string>
-    <key>CFBundleExecutable</key>
+	<key>CFBundleIdentifier</key>
-    <string>tart</string>
+	<string>org.cirruslabs.tart</string>
-    <key>LSBackgroundOnly</key>
+	<key>CFBundleExecutable</key>
-    <string>1</string>
+	<string>tart</string>
-    <key>CFBundleIconFiles</key>
+	<key>LSBackgroundOnly</key>
-    <array>
+	<string>1</string>
-        <string>AppIcon.png</string>
+	<key>CFBundleIconFiles</key>
-    </array>
+	<array>
-    <key>NSAppTransportSecurity</key>
+		<string>AppIcon.png</string>
-    <dict>
+	</array>
-        <key>NSAllowsArbitraryLoads</key>
+	<key>NSAppTransportSecurity</key>
-        <true/>
+	<dict>
-    </dict>
+		<key>NSAllowsArbitraryLoads</key>
+		<true/>
+	</dict>
 </dict>
 </plist>

Sources/tart/Commands/Clone.swift

@@ -9,12 +9,10 @@ struct Clone: AsyncParsableCommand {
     Creates a local virtual machine by cloning either a remote or another local virtual machine.
 
     Due to copy-on-write magic in Apple File System, a cloned VM won't actually claim all the space right away.
-    Only changes to a cloned disk will be written and claim new space. By default, Tart checks available capacity
+    Only changes to a cloned disk will be written and claim new space. This also speeds up clones enormously.
-    in Tart's home directory and checks if there is enough space for the worst possible scenario: when the whole disk
-    will be modified.
 
-    This behaviour can be disabled by setting TART_NO_AUTO_PRUNE environment variable. This might be helpful
+    By default, Tart checks available capacity in Tart's home directory and tries to reclaim minimum possible storage for the cloned image
-    for use cases when the original image is very big and a workload is known to only modify a fraction of the cloned disk.
+    to fit. This behaviour is called "automatic pruning" and can be disabled by setting TART_NO_AUTO_PRUNE environment variable.
     """
   )
 
@@ -30,6 +28,9 @@ struct Clone: AsyncParsableCommand {
   @Option(help: "network concurrency to use when pulling a remote VM from the OCI-compatible registry")
   var concurrency: UInt = 4
 
+  @Flag(help: .hidden)
+  var deduplicate: Bool = false
+
   func validate() throws {
     if newName.contains("/") {
       throw ValidationError("<new-name> should be a local name")
@@ -47,7 +48,7 @@ struct Clone: AsyncParsableCommand {
     if let remoteName = try? RemoteName(sourceName), !ociStorage.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, insecure: insecure)
-      try await ociStorage.pull(remoteName, registry: registry, concurrency: concurrency)
+      try await ociStorage.pull(remoteName, registry: registry, concurrency: concurrency, deduplicate: deduplicate)
     }
 
     let sourceVM = try VMStorageHelper.open(sourceName)

Sources/tart/Commands/Pull.swift

@@ -9,8 +9,8 @@ struct Pull: AsyncParsableCommand {
     Pulls a virtual machine from a remote OCI-compatible registry. Supports authorization via Keychain (see "tart login --help"),
     Docker credential helpers defined in ~/.docker/config.json or via TART_REGISTRY_USERNAME/TART_REGISTRY_PASSWORD environment variables.
 
-    By default, Tart checks available capacity in Tart's home directory and tries to reclaim minimum possible storage for the remote image to fit via "tart prune".
+    By default, Tart checks available capacity in Tart's home directory and tries to reclaim minimum possible storage for the remote image
-    This behaviour can be disabled by setting TART_NO_AUTO_PRUNE environment variable.
+    to fit. This behaviour is called "automatic pruning" and can be disabled by setting TART_NO_AUTO_PRUNE environment variable.
     """
   )
 
@@ -23,6 +23,9 @@ struct Pull: AsyncParsableCommand {
   @Option(help: "network concurrency to use when pulling a remote VM from the OCI-compatible registry")
   var concurrency: UInt = 4
 
+  @Flag(help: .hidden)
+  var deduplicate: Bool = false
+
   func validate() throws {
     if concurrency < 1 {
       throw ValidationError("network concurrency cannot be less than 1")
@@ -43,6 +46,6 @@ struct Pull: AsyncParsableCommand {
 
     defaultLogger.appendNewLine("pulling \(remoteName)...")
 
-    try await VMStorageOCI().pull(remoteName, registry: registry, concurrency: concurrency)
+    try await VMStorageOCI().pull(remoteName, registry: registry, concurrency: concurrency, deduplicate: deduplicate)
   }
 }

Sources/tart/Credentials/DockerConfigCredentialsProvider.swift

@@ -39,9 +39,10 @@ class DockerConfigCredentialsProvider: CredentialsProvider {
     inPipe.fileHandleForWriting.write("\(host)\n".data(using: .utf8)!)
     inPipe.fileHandleForWriting.closeFile()
 
+    let outputData = try outPipe.fileHandleForReading.readToEnd()
+
     process.waitUntilExit()
 
-    let outputData = try outPipe.fileHandleForReading.readToEnd()
     if !(process.terminationReason == .exit && process.terminationStatus == 0) {
       if let outputData = outputData {
         print(String(decoding: outputData, as: UTF8.self))

Sources/tart/MACAddressResolver/ARPCache.swift

@@ -52,6 +52,11 @@ struct ARPCache {
     process.standardInput = FileHandle.nullDevice
 
     try process.run()
+
+    guard let arpCommandOutput = try pipe.fileHandleForReading.readToEnd() else {
+      throw ARPCommandYieldedInvalidOutputError(explanation: "empty output")
+    }
+
     process.waitUntilExit()
 
     if !(process.terminationReason == .exit && process.terminationStatus == 0) {
@@ -60,10 +65,6 @@ struct ARPCache {
         terminationStatus: process.terminationStatus)
     }
 
-    guard let arpCommandOutput = try pipe.fileHandleForReading.readToEnd() else {
-      throw ARPCommandYieldedInvalidOutputError(explanation: "empty output")
-    }
-
     self.arpCommandOutput = arpCommandOutput
   }
 

Sources/tart/OCI/Layerizer/Disk.swift

@@ -2,5 +2,5 @@ import Foundation
 
 protocol Disk {
   static func push(diskURL: URL, registry: Registry, chunkSizeMb: Int, concurrency: UInt, progress: Progress) async throws -> [OCIManifestLayer]
-  static func pull(registry: Registry, diskLayers: [OCIManifestLayer], diskURL: URL, concurrency: UInt, progress: Progress, localLayerCache: LocalLayerCache?) async throws
+  static func pull(registry: Registry, diskLayers: [OCIManifestLayer], diskURL: URL, concurrency: UInt, progress: Progress, localLayerCache: LocalLayerCache?, deduplicate: Bool) async throws
 }

Sources/tart/OCI/Layerizer/DiskV1.swift

@@ -45,7 +45,7 @@ class DiskV1: Disk {
     return pushedLayers
   }
 
-  static func pull(registry: Registry, diskLayers: [OCIManifestLayer], diskURL: URL, concurrency: UInt, progress: Progress, localLayerCache: LocalLayerCache? = nil) async throws {
+  static func pull(registry: Registry, diskLayers: [OCIManifestLayer], diskURL: URL, concurrency: UInt, progress: Progress, localLayerCache: LocalLayerCache? = nil, deduplicate: Bool = false) async throws {
     if !FileManager.default.createFile(atPath: diskURL.path, contents: nil) {
       throw OCIError.FailedToCreateVmFile
     }

Sources/tart/OCI/Layerizer/DiskV2.swift

@@ -69,12 +69,12 @@ class DiskV2: Disk {
     }
   }
 
-  static func pull(registry: Registry, diskLayers: [OCIManifestLayer], diskURL: URL, concurrency: UInt, progress: Progress, localLayerCache: LocalLayerCache? = nil) async throws {
+  static func pull(registry: Registry, diskLayers: [OCIManifestLayer], diskURL: URL, concurrency: UInt, progress: Progress, localLayerCache: LocalLayerCache? = nil, deduplicate: Bool = false) async throws {
     // Support resumable pulls
     let pullResumed = FileManager.default.fileExists(atPath: diskURL.path)
 
     if !pullResumed {
-      if let localLayerCache = localLayerCache {
+      if deduplicate, let localLayerCache = localLayerCache {
         // Clone the local layer cache's disk and use it as a base, potentially
         // reducing the space usage since some blocks won't be written at all
         try FileManager.default.copyItem(at: localLayerCache.diskURL, to: diskURL)
@@ -151,26 +151,31 @@ class DiskV2: Disk {
 
           // Also open the disk file for reading and verifying
           // its contents in case the local layer cache is used
-          let rdisk: FileHandle? = if localLayerCache != nil {
+          let rdisk: FileHandle? = if deduplicate && localLayerCache != nil {
             try FileHandle(forReadingFrom: diskURL)
           } else {
             nil
           }
 
-          // Check if we already have this layer contents in the local layer cache
+          // Check if we already have this layer contents in the local layer cache,
-          if let localLayerCache = localLayerCache, let localLayerInfo = localLayerCache.findInfo(digest: diskLayer.digest, offsetHint: diskWritingOffset) {
+          // or perhaps even on the cloned disk (when the deduplication is enabled)
-            // indicates that the locally cloned disk image has the same content at the given offset
+          if let localLayerCache = localLayerCache,
-            let localHit = localLayerInfo.uncompressedContentDigest == uncompressedLayerContentDigest
+             let localLayerInfo = localLayerCache.findInfo(digest: diskLayer.digest, offsetHint: diskWritingOffset),
-              && localLayerInfo.range.lowerBound == diskWritingOffset
+             localLayerInfo.uncompressedContentDigest == uncompressedLayerContentDigest {
-            // doesn't seem that localHit can ever be false if the localLayerCache is not nil
+            if deduplicate && localLayerInfo.range.lowerBound == diskWritingOffset {
-            // but let's just add extra safety here and check it
+              // Do nothing, because the data is already on the disk that we've inherited from
-            if !localHit {
+            } else {
               // Fulfil the layer contents from the local blob cache
               let data = localLayerCache.subdata(localLayerInfo.range)
               _ = try zeroSkippingWrite(disk, rdisk, fsBlockSize, diskWritingOffset, data)
             }
+
             try disk.close()
 
+            if let rdisk = rdisk {
+              try rdisk.close()
+            }
+
             // Update the progress
             progress.completedUnitCount += Int64(diskLayer.size)
 
@@ -198,6 +203,10 @@ class DiskV2: Disk {
           try filter.finalize()
 
           try disk.close()
+
+          if let rdisk = rdisk {
+            try rdisk.close()
+          }
         }
 
         globalDiskWritingOffset += uncompressedLayerSize

Sources/tart/OCI/Reference/Generated/ReferenceBaseListener.swift

@@ -1,4 +1,4 @@
-// Generated from java-escape by ANTLR 4.11.1
+// Generated from Reference.g4 by ANTLR 4.13.2
 
 import Antlr4
 

Sources/tart/OCI/Reference/Generated/ReferenceLexer.swift

@@ -1,4 +1,4 @@
-// Generated from java-escape by ANTLR 4.11.1
+// Generated from Reference.g4 by ANTLR 4.13.2
 import Antlr4
 
 open class ReferenceLexer: Lexer {
@@ -49,7 +49,7 @@ open class ReferenceLexer: Lexer {
 
 	public
 	required init(_ input: CharStream) {
-	    RuntimeMetaData.checkVersion("4.11.1", RuntimeMetaData.VERSION)
+	    RuntimeMetaData.checkVersion("4.13.2", RuntimeMetaData.VERSION)
 		super.init(input)
 		_interp = LexerATNSimulator(self, ReferenceLexer._ATN, ReferenceLexer._decisionToDFA, ReferenceLexer._sharedContextCache)
 	}

Sources/tart/OCI/Reference/Generated/ReferenceListener.swift

@@ -1,4 +1,4 @@
-// Generated from java-escape by ANTLR 4.11.1
+// Generated from Reference.g4 by ANTLR 4.13.2
 import Antlr4
 
 /**

Sources/tart/OCI/Reference/Generated/ReferenceParser.swift

@@ -1,4 +1,4 @@
-// Generated from java-escape by ANTLR 4.11.1
+// Generated from Reference.g4 by ANTLR 4.13.2
 import Antlr4
 
 open class ReferenceParser: Parser {
@@ -41,7 +41,7 @@ open class ReferenceParser: Parser {
 	static let VOCABULARY = Vocabulary(_LITERAL_NAMES, _SYMBOLIC_NAMES)
 
 	override open
-	func getGrammarFileName() -> String { return "java-escape" }
+	func getGrammarFileName() -> String { return "Reference.g4" }
 
 	override open
 	func getRuleNames() -> [String] { return ReferenceParser.ruleNames }
@@ -60,7 +60,7 @@ open class ReferenceParser: Parser {
 
 	override public
 	init(_ input:TokenStream) throws {
-	    RuntimeMetaData.checkVersion("4.11.1", RuntimeMetaData.VERSION)
+	    RuntimeMetaData.checkVersion("4.13.2", RuntimeMetaData.VERSION)
 		try super.init(input)
 		_interp = ParserATNSimulator(self,ReferenceParser._ATN,ReferenceParser._decisionToDFA, ReferenceParser._sharedContextCache)
 	}
@@ -460,7 +460,7 @@ open class ReferenceParser: Parser {
 		 		setState(63)
 		 		try _errHandler.sync(self)
 		 		_la = try _input.LA(1)
-		 		if ((Int64(_la) & ~0x3f) == 0 && ((Int64(1) << _la) & 88) != 0) {
+		 		if (((Int64(_la) & ~0x3f) == 0 && ((Int64(1) << _la) & 88) != 0)) {
 		 			setState(62)
 		 			try separator()
 
@@ -611,7 +611,7 @@ open class ReferenceParser: Parser {
 		 	setState(84)
 		 	try _errHandler.sync(self)
 		 	_la = try _input.LA(1)
-		 	while ((Int64(_la) & ~0x3f) == 0 && ((Int64(1) << _la) & 88) != 0) {
+		 	while (((Int64(_la) & ~0x3f) == 0 && ((Int64(1) << _la) & 88) != 0)) {
 		 		setState(79)
 		 		try separator()
 		 		setState(80)
@@ -664,7 +664,7 @@ open class ReferenceParser: Parser {
 		 	try enterOuterAlt(_localctx, 1)
 		 	setState(87)
 		 	_la = try _input.LA(1)
-		 	if (!((Int64(_la) & ~0x3f) == 0 && ((Int64(1) << _la) & 88) != 0)) {
+		 	if (!(((Int64(_la) & ~0x3f) == 0 && ((Int64(1) << _la) & 88) != 0))) {
 		 	try _errHandler.recoverInline(self)
 		 	}
 		 	else {

Sources/tart/OCI/Registry.swift

@@ -327,12 +327,12 @@ class Registry {
       request.httpBody = body
     }
 
-    var (channel, response) = try await authAwareRequest(request: request, viaFile: viaFile)
+    var (channel, response) = try await authAwareRequest(request: request, viaFile: viaFile, doAuth: doAuth)
 
     if doAuth && response.statusCode == HTTPCode.Unauthorized.rawValue {
       _ = try await channel.asData()
       try await auth(response: response)
-      (channel, response) = try await authAwareRequest(request: request, viaFile: viaFile)
+      (channel, response) = try await authAwareRequest(request: request, viaFile: viaFile, doAuth: doAuth)
     }
 
     return (channel, response)
@@ -413,11 +413,13 @@ class Registry {
     return nil
   }
 
-  private func authAwareRequest(request: URLRequest, viaFile: Bool = false) async throws -> (AsyncThrowingChannel<Data, Error>, HTTPURLResponse) {
+  private func authAwareRequest(request: URLRequest, viaFile: Bool = false, doAuth: Bool) async throws -> (AsyncThrowingChannel<Data, Error>, HTTPURLResponse) {
     var request = request
 
-    if let (name, value) = await authenticationKeeper.header() {
+    if doAuth {
-      request.addValue(value, forHTTPHeaderField: name)
+      if let (name, value) = await authenticationKeeper.header() {
+        request.addValue(value, forHTTPHeaderField: name)
+      }
     }
 
     request.setValue("Tart/\(CI.version) (\(DeviceInfo.os); \(DeviceInfo.model))",

Sources/tart/PIDLock.swift

@@ -11,7 +11,7 @@ class PIDLock {
     if fd == -1 {
       let details = Errno(rawValue: CInt(errno))
 
-      throw RuntimeError.PIDLockFailed("failed to open lock file \(url): \(details)")
+      throw RuntimeError.PIDLockMissing("failed to open lock file \(url): \(details)")
     }
   }
 

Sources/tart/VM.swift

@@ -317,15 +317,19 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
     // Audio
     let soundDeviceConfiguration = VZVirtioSoundDeviceConfiguration()
 
-    let inputAudioStreamConfiguration = VZVirtioSoundDeviceInputStreamConfiguration()
-    let outputAudioStreamConfiguration = VZVirtioSoundDeviceOutputStreamConfiguration()
-
     if audio && !suspendable {
+      let inputAudioStreamConfiguration = VZVirtioSoundDeviceInputStreamConfiguration()
+      let outputAudioStreamConfiguration = VZVirtioSoundDeviceOutputStreamConfiguration()
+
       inputAudioStreamConfiguration.source = VZHostAudioInputStreamSource()
       outputAudioStreamConfiguration.sink = VZHostAudioOutputStreamSink()
+
+      soundDeviceConfiguration.streams = [inputAudioStreamConfiguration, outputAudioStreamConfiguration]
+    } else {
+      // just a null speaker
+      soundDeviceConfiguration.streams = [VZVirtioSoundDeviceOutputStreamConfiguration()]
     }
 
-    soundDeviceConfiguration.streams = [inputAudioStreamConfiguration, outputAudioStreamConfiguration]
     configuration.audioDevices = [soundDeviceConfiguration]
 
     // Keyboard and mouse

Sources/tart/VMDirectory+OCI.swift

@@ -11,7 +11,7 @@ enum OCIError: Error {
 }
 
 extension VMDirectory {
-  func pullFromRegistry(registry: Registry, manifest: OCIManifest, concurrency: UInt, localLayerCache: LocalLayerCache?) async throws {
+  func pullFromRegistry(registry: Registry, manifest: OCIManifest, concurrency: UInt, localLayerCache: LocalLayerCache?, deduplicate: Bool) async throws {
     // Pull VM's config file layer and re-serialize it into a config file
     let configLayers = manifest.layers.filter {
       $0.mediaType == configMediaType
@@ -54,12 +54,13 @@ extension VMDirectory {
     do {
       try await diskImplType.pull(registry: registry, diskLayers: layers, diskURL: diskURL,
                                   concurrency: concurrency, progress: progress,
-                                  localLayerCache: localLayerCache)
+                                  localLayerCache: localLayerCache,
+                                  deduplicate: deduplicate)
     } catch let error where error is FilterError {
       throw RuntimeError.PullFailed("failed to decompress disk: \(error.localizedDescription)")
     }
 
-    if let llc = localLayerCache {
+    if deduplicate, let llc = localLayerCache {
       // set custom attribute to remember deduplicated bytes
       diskURL.setDeduplicatedBytes(llc.deduplicatedBytes)
     }

Sources/tart/VMStorageHelper.swift

@@ -24,6 +24,8 @@ class VMStorageHelper {
   private static func missingVMWrap<R: Any>(_ name: String, closure: () throws -> R) throws -> R {
     do {
       return try closure()
+    } catch RuntimeError.PIDLockMissing {
+      throw RuntimeError.VMDoesNotExist(name: name)
     } catch {
       if error.isFileNotFound() {
         throw RuntimeError.VMDoesNotExist(name: name)
@@ -59,6 +61,7 @@ enum RuntimeError : Error {
   case InvalidDiskSize(_ message: String)
   case FailedToUpdateAccessDate(_ message: String)
   case PIDLockFailed(_ message: String)
+  case PIDLockMissing(_ message: String)
   case FailedToParseRemoteName(_ message: String)
   case VMTerminationFailed(_ message: String)
   case ImproperlyFormattedHost(_ host: String, _ hint: String)
@@ -105,6 +108,8 @@ extension RuntimeError : CustomStringConvertible {
       return message
     case .PIDLockFailed(let message):
       return message
+    case .PIDLockMissing(let message):
+      return message
     case .FailedToParseRemoteName(let cause):
       return "failed to parse remote name: \(cause)"
     case .VMTerminationFailed(let message):

Sources/tart/VMStorageOCI.swift

@@ -140,7 +140,7 @@ class VMStorageOCI: PrunableStorage {
     try list().filter { (_, _, isSymlink) in !isSymlink }.map { (_, vmDir, _) in vmDir }
   }
 
-  func pull(_ name: RemoteName, registry: Registry, concurrency: UInt) async throws {
+  func pull(_ name: RemoteName, registry: Registry, concurrency: UInt, deduplicate: Bool) async throws {
     SentrySDK.configureScope { scope in
       scope.setContext(value: ["imageName": name.description], key: "OCI")
     }
@@ -203,10 +203,14 @@ class VMStorageOCI: PrunableStorage {
           if let llc = localLayerCache {
             let deduplicatedHuman = ByteCountFormatter.string(fromByteCount: Int64(llc.deduplicatedBytes), countStyle: .file)
 
-            defaultLogger.appendNewLine("found an image \(llc.name) that will allow us to deduplicate \(deduplicatedHuman), using it as a base...")
+            if deduplicate {
+              defaultLogger.appendNewLine("found an image \(llc.name) that will allow us to deduplicate \(deduplicatedHuman), using it as a base...")
+            } else {
+              defaultLogger.appendNewLine("found an image \(llc.name) that will allow us to avoid fetching \(deduplicatedHuman), will try use it...")
+            }
           }
 
-          try await tmpVMDir.pullFromRegistry(registry: registry, manifest: manifest, concurrency: concurrency, localLayerCache: localLayerCache)
+          try await tmpVMDir.pullFromRegistry(registry: registry, manifest: manifest, concurrency: concurrency, localLayerCache: localLayerCache, deduplicate: deduplicate)
         } recoverFromFailure: { error in
           if error is Retryable {
             print("Error: \(error.localizedDescription)")

docs/faq.md

@@ -90,3 +90,21 @@ Instead of Anka Registry, Tart can work with any OCI-compatible container regist
 and scalable experience for distributing virtual machines.
 
 Tart doesn't yet have an analogue of Anka Controller for managing long living VMs but [soon will be](https://github.com/cirruslabs/tart/issues/372).
+
+## Automatic pruning
+
+`tart pull` and `tart clone` commands check the remaining space available on the volume associated with `TART_HOME` directory (defaults to `~/.tart`) before pulling or cloning anything.
+
+In case there's not enough space to fit the newly pulled or cloned VM image, Tart will remove the least recently accessed VMs from OCI cache and `.ipsw` files from IPSW cache until enough free space is available.
+
+To disable this functionality, set the `TART_NO_AUTO_PRUNE` environment variable either globally:
+
+```shell
+export TART_NO_AUTO_PRUNE=
+```
+
+...or per `tart pull` and `tart clone` invocation as follows:
+
+```shell
+TART_NO_AUTO_PRUNE= tart pull ...
+```