chore(telemetry): simplify by removing conditional imports; OTEL is now a hard dependency and only initializes when endpoint is set

- Initialize OTEL only when OTEL_EXPORTER_OTLP_ENDPOINT is set
- Support both OTLP/gRPC (host:port) and OTLP/HTTP (http[s]://...)
- Map CIRRUS_SENTRY_TAGS to OTEL resource attributes
- Replace Sentry transactions/events with OTEL spans + attributes
- Add Telemetry wrapper and update code to record errors + flush
- Remove sentry-cocoa dependency; add opentelemetry-swift + NIO

This preserves existing tags and measurements under OTEL and keeps telemetry disabled by default.

CONTRIBUTING.md

@@ -29,6 +29,7 @@ Table of Contents
 
 1. Code should follow camel case
 2. Code should follow [SwiftFormat](https://github.com/nicklockwood/SwiftFormat#swift-package-manager-plugin) guidelines. You can auto-format the code by running the following command:
+
 ```bash
 swift package plugin --allow-writing-to-package-directory swiftformat --cache ignore .
 ```

Package.resolved

@@ -1,5 +1,5 @@
 {
-  "originHash" : "c5371137580239f6928cf64425e754e77680bf24430b50f02dad5558c23f68b0",
+  "originHash" : "aa0a5df26b9e35d1908d6876d045af7ce1899086d641507e5faa9d1f9bd29787",
   "pins" : [
     {
       "identity" : "antlr4",
@@ -46,6 +46,24 @@
         "version" : "1.24.2"
       }
     },
+    {
+      "identity" : "opentelemetry-swift",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/open-telemetry/opentelemetry-swift",
+      "state" : {
+        "revision" : "6a2c29d53ff0b543b551b2221538bd3d0206c6d6",
+        "version" : "1.15.0"
+      }
+    },
+    {
+      "identity" : "opentracing-objc",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/undefinedlabs/opentracing-objc",
+      "state" : {
+        "revision" : "18c1a35ca966236cee0c5a714a51a73ff33384c1",
+        "version" : "0.5.2"
+      }
+    },
     {
       "identity" : "semaphore",
       "kind" : "remoteSourceControl",
@@ -55,15 +73,6 @@
         "version" : "0.1.0"
       }
     },
-    {
-      "identity" : "sentry-cocoa",
-      "kind" : "remoteSourceControl",
-      "location" : "https://github.com/getsentry/sentry-cocoa",
-      "state" : {
-        "revision" : "65b3d2a7608685e8d4a37c68fa2c64f28d0b537e",
-        "version" : "8.51.1"
-      }
-    },
     {
       "identity" : "swift-algorithms",
       "kind" : "remoteSourceControl",
@@ -78,8 +87,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-argument-parser",
       "state" : {
-        "revision" : "41982a3656a71c768319979febd796c6fd111d5c",
-        "version" : "1.5.0"
+        "revision" : "309a47b2b1d9b5e991f36961c983ecec72275be3",
+        "version" : "1.6.1"
       }
     },
     {
@@ -127,6 +136,15 @@
         "version" : "1.6.1"
       }
     },
+    {
+      "identity" : "swift-metrics",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-metrics.git",
+      "state" : {
+        "revision" : "4c83e1cdf4ba538ef6e43a9bbd0bcc33a0ca46e3",
+        "version" : "2.7.0"
+      }
+    },
     {
       "identity" : "swift-nio",
       "kind" : "remoteSourceControl",
@@ -261,6 +279,15 @@
         "branch" : "master",
         "revision" : "e03289289155b4e7aa565e32862f9cb42140596a"
       }
+    },
+    {
+      "identity" : "thrift-swift",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/undefinedlabs/Thrift-Swift",
+      "state" : {
+        "revision" : "18ff09e6b30e589ed38f90a1af23e193b8ecef8e",
+        "version" : "1.1.2"
+      }
     }
   ],
   "version" : 3

Package.swift

@@ -10,14 +10,14 @@ let package = Package(
     .executable(name: "tart", targets: ["tart"])
   ],
   dependencies: [
-    .package(url: "https://github.com/apple/swift-argument-parser", from: "1.3.1"),
+    .package(url: "https://github.com/apple/swift-argument-parser", from: "1.6.1"),
     .package(url: "https://github.com/mhdhejazi/Dynamic", branch: "master"),
     .package(url: "https://github.com/apple/swift-algorithms", from: "1.2.0"),
     .package(url: "https://github.com/malcommac/SwiftDate", from: "7.0.0"),
     .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: "8.51.1"),
+    .package(url: "https://github.com/open-telemetry/opentelemetry-swift", from: "1.7.0"),
     .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"),
@@ -25,6 +25,7 @@ let package = Package(
     .package(url: "https://github.com/fumoboy007/swift-retry", from: "0.2.3"),
     .package(url: "https://github.com/jozefizso/swift-xattr", from: "3.0.0"),
     .package(url: "https://github.com/grpc/grpc-swift.git", .upToNextMajor(from: "1.24.2")),
+    .package(url: "https://github.com/apple/swift-nio.git", from: "2.83.0"),
     .package(url: "https://buf.build/gen/swift/git/1.24.2-00000000000000-17d7dedafb88.1/cirruslabs_tart-guest-agent_grpc_swift.git", revision: "1.24.2-00000000000000-17d7dedafb88.1"),
   ],
   targets: [
@@ -35,7 +36,11 @@ let package = Package(
       .product(name: "SwiftDate", package: "SwiftDate"),
       .product(name: "Antlr4Static", package: "Antlr4"),
       .product(name: "Atomics", package: "swift-atomics"),
-      .product(name: "Sentry", package: "sentry-cocoa"),
+      .product(name: "OpenTelemetryApi", package: "opentelemetry-swift"),
+      .product(name: "OpenTelemetrySdk", package: "opentelemetry-swift"),
+      .product(name: "OpenTelemetryProtocolExporter", package: "opentelemetry-swift"),
+      .product(name: "OpenTelemetryProtocolExporterHTTP", package: "opentelemetry-swift"),
+      .product(name: "NIO", package: "swift-nio"),
       .product(name: "TextTable", package: "TextTable"),
       .product(name: "Sysctl", package: "swift-sysctl"),
       .product(name: "SwiftRadix", package: "SwiftRadix"),

README.md

@@ -66,8 +66,8 @@ Try running a Tart VM on your Apple Silicon device running macOS 13.0 (Ventura)
 
 ```bash
 brew install cirruslabs/cli/tart
-tart clone ghcr.io/cirruslabs/macos-sequoia-base:latest sequoia-base
-tart run sequoia-base
+tart clone ghcr.io/cirruslabs/macos-tahoe-base:latest tahoe-base
+tart run tahoe-base
 ```
 
 Please check the [official documentation](https://tart.run) for more information and/or feel free to use [discussions](https://github.com/cirruslabs/tart/discussions)

Sources/tart/Commands/Clone.swift

@@ -31,6 +31,9 @@ struct Clone: AsyncParsableCommand {
   @Flag(help: .hidden)
   var deduplicate: Bool = false
 
+  @Option(help: ArgumentHelp("limit automatic pruning to n gigabytes", valueName: "n"))
+  var pruneLimit: UInt = 100
+
   func validate() throws {
     if newName.contains("/") {
       throw ValidationError("<new-name> should be a local name")
@@ -76,8 +79,10 @@ struct Clone: AsyncParsableCommand {
       //
       // So, once we clone the VM let's try to claim the rest of space for the VM to run without errors.
       let unallocatedBytes = try sourceVM.sizeBytes() - sourceVM.allocatedSizeBytes()
-      if unallocatedBytes > 0 {
-        try Prune.reclaimIfNeeded(UInt64(unallocatedBytes), sourceVM)
+      // Avoid reclaiming an excessive amount of disk space.
+      let reclaimBytes = min(unallocatedBytes, Int(pruneLimit) * 1024 * 1024 * 1024)
+      if reclaimBytes > 0 {
+        try Prune.reclaimIfNeeded(UInt64(reclaimBytes), sourceVM)
       }
     }, onCancel: {
       try? FileManager.default.removeItem(at: tmpVMDir.baseURL)

Sources/tart/Commands/Exec.swift

@@ -87,11 +87,13 @@ struct Exec: AsyncParsableCommand {
         $0.args = Array(command.dropFirst(1))
         $0.interactive = interactive
         $0.tty = tty
-        $0.terminalSize = .with {
-          let (width, height) = try! Term.GetSize()
+        if tty {
+          $0.terminalSize = .with {
+            let (width, height) = try! Term.GetSize()
 
-          $0.cols = UInt32(width)
-          $0.rows = UInt32(height)
+            $0.cols = UInt32(width)
+            $0.rows = UInt32(height)
+          }
         }
       })
     })
@@ -100,28 +102,61 @@ struct Exec: AsyncParsableCommand {
     try await withThrowingTaskGroup { group in
       // Stream host's standard input if interactive mode is enabled
       if interactive {
-        let stdinStream = AsyncStream<Data> { continuation in
+        let stdinStream = AsyncThrowingStream<Data, Error> { continuation in
           let handle = FileHandle.standardInput
 
-          handle.readabilityHandler = { handle in
-            let data = handle.availableData
+          if isRegularFile(handle.fileDescriptor) {
+            // Standard input can be a regular file when input redirection (<) is used,
+            // in which case the handle won't receive any new readability events, so we
+            // just read the file normally here in chunks and consider done with it
+            //
+            // Ideally this is best handled by using non-blocking I/O, but Swift's
+            // standard library only offers inefficient bytes[1] property and SwiftNIO's
+            // NIOFileSystem doesn't seem to support opening raw file descriptors.
+            //
+            // [1]: https://developer.apple.com/documentation/foundation/filehandle/bytes
+            while true {
+              do {
+                let data = try handle.read(upToCount: 64 * 1024)
+                if let data = data {
+                  continuation.yield(data)
+                } else {
+                  continuation.finish()
+                  break
+                }
+              } catch (let error) {
+                continuation.finish(throwing: error)
+                break
+              }
+            }
+          } else {
+            handle.readabilityHandler = { handle in
+              let data = handle.availableData
 
-            continuation.yield(data)
-
-            if data.isEmpty {
-              continuation.finish()
+              if data.isEmpty {
+                continuation.finish()
+              } else {
+                continuation.yield(data)
+              }
             }
           }
         }
 
         group.addTask {
-          for await stdinData in stdinStream {
+          for try await stdinData in stdinStream {
             try await execCall.requestStream.send(.with {
               $0.type = .standardInput(.with {
                 $0.data = stdinData
               })
             })
           }
+
+          // Signal EOF as we're done reading standard input
+          try await execCall.requestStream.send(.with {
+            $0.type = .standardInput(.with {
+              $0.data = Data()
+            })
+          })
         }
       }
 
@@ -178,3 +213,13 @@ struct Exec: AsyncParsableCommand {
     }
   }
 }
+
+private func isRegularFile(_ fileDescriptor: Int32) -> Bool {
+  var stat = stat()
+
+  if fstat(fileDescriptor, &stat) != 0 {
+    return false
+  }
+
+  return (stat.st_mode & S_IFMT) == S_IFREG
+}

Sources/tart/Commands/IP.swift

@@ -2,7 +2,6 @@ import ArgumentParser
 import Foundation
 import Network
 import SystemConfiguration
-import Sentry
 
 enum IPResolutionStrategy: String, ExpressibleByArgument, CaseIterable {
   case dhcp, arp, agent

Sources/tart/Commands/Prune.swift

@@ -1,6 +1,6 @@
 import ArgumentParser
 import Dispatch
-import Sentry
+// Telemetry integration is encapsulated in Telemetry.swift
 import SwiftUI
 import SwiftDate
 
@@ -109,9 +109,10 @@ struct Prune: AsyncParsableCommand {
       return
     }
 
-    SentrySDK.configureScope { scope in
-      scope.setContext(value: ["requiredBytes": requiredBytes], key: "Prune")
-    }
+    // Record desired reclaim size as an event context
+    Telemetry.addEvent("Prune.required", attributes: [
+      "requiredBytes": .int(Int(requiredBytes))
+    ])
 
     // Figure out how much disk space is available
     let attrs = try Config().tartCacheDir.resourceValues(forKeys: [
@@ -123,18 +124,17 @@ struct Prune: AsyncParsableCommand {
       UInt64(attrs.volumeAvailableCapacityForImportantUsage!)
     )
 
-    SentrySDK.configureScope { scope in
-      scope.setContext(value: [
-        "volumeAvailableCapacity": attrs.volumeAvailableCapacity!,
-        "volumeAvailableCapacityForImportantUsage": attrs.volumeAvailableCapacityForImportantUsage!,
-        "volumeAvailableCapacityCalculated": volumeAvailableCapacityCalculated
-      ], key: "Prune")
-    }
+    Telemetry.addEvent("Prune.capacity", attributes: [
+      "volumeAvailableCapacity": .int(Int(attrs.volumeAvailableCapacity!)),
+      "volumeAvailableCapacityForImportantUsage": .int(Int(attrs.volumeAvailableCapacityForImportantUsage!)),
+      "volumeAvailableCapacityCalculated": .int(Int(volumeAvailableCapacityCalculated))
+    ])
 
     if volumeAvailableCapacityCalculated <= 0 {
-      SentrySDK.capture(message: "Zero volume capacity reported") { scope in
-        scope.setLevel(.warning)
-      }
+      Telemetry.addEvent("Prune.warning", attributes: [
+        "message": .string("Zero volume capacity reported"),
+        "level": .string("warning")
+      ])
 
       return
     }
@@ -149,7 +149,7 @@ struct Prune: AsyncParsableCommand {
   }
 
   private static func reclaimIfPossible(_ reclaimBytes: UInt64, _ initiator: Prunable? = nil) throws {
-    let transaction = SentrySDK.startTransaction(name: "Pruning cache", operation: "prune", bindToScope: true)
+    let transaction = Telemetry.startTransaction(name: "Pruning cache", operation: "prune", bindToScope: true)
     defer { transaction.finish() }
 
     let prunableStorages: [PrunableStorage] = [VMStorageOCI(), try IPSWCache()]
@@ -177,13 +177,16 @@ struct Prune: AsyncParsableCommand {
         continue
       }
 
-      try SentrySDK.span?.setData(value: prunable.allocatedSizeBytes(), key: prunable.url.path)
+      Telemetry.addEvent("Prune.prunable", attributes: [
+        "path": .string(prunable.url.path),
+        "size_bytes": .int(try prunable.allocatedSizeBytes())
+      ])
 
       cacheReclaimedBytes += try prunable.allocatedSizeBytes()
 
       try prunable.delete()
     }
 
-    SentrySDK.span?.setMeasurement(name: "gc_disk_reclaimed", value: cacheReclaimedBytes as NSNumber, unit: MeasurementUnitInformation.byte);
+    Telemetry.setAttribute("gc_disk_reclaimed", .int(cacheReclaimedBytes))
   }
 }

Sources/tart/Commands/Run.swift

@@ -4,7 +4,7 @@ import Darwin
 import Dispatch
 import SwiftUI
 import Virtualization
-import Sentry
+// Telemetry integration is encapsulated in Telemetry.swift
 import System
 
 var vm: VM?
@@ -116,10 +116,6 @@ struct Run: AsyncParsableCommand {
   #endif
   var vncExperimental: Bool = false
 
-  // Note that the valueName here should really be "path[:options]" instead of just "path",
-  // see ArgumentParser issue[1] for more details.
-  //
-  // [1]: https://github.com/apple/swift-argument-parser/issues/761
   @Option(help: ArgumentHelp("""
   Additional disk attachments with an optional read-only and synchronization options in the form of path[:options] (e.g. --disk="disk.bin", --disk="ubuntu.iso:ro", --disk="/dev/disk0", --disk "ghcr.io/cirruslabs/xcode:16.0:ro" or --disk="nbd://localhost:10809/myDisk:sync=none")
   """, discussion: """
@@ -143,7 +139,7 @@ struct Run: AsyncParsableCommand {
   To work around this pass TART_HOME explicitly:
 
   sudo TART_HOME="$HOME/.tart" tart run sequoia --disk=/dev/disk0
-  """, valueName: "path"), completion: .file())
+  """, valueName: "path[:options]"), completion: .file())
   var disk: [String] = []
 
   #if arch(arm64)
@@ -162,10 +158,6 @@ struct Run: AsyncParsableCommand {
   #endif
   var rosettaTag: String?
 
-  // Note that the valueName here should really be "[name:]path[:options]" instead of just "path",
-  // see ArgumentParser issue[1] for more details.
-  //
-  // [1]: https://github.com/apple/swift-argument-parser/issues/761
   @Option(help: ArgumentHelp("Additional directory shares with an optional read-only and mount tag options in the form of [name:]path[:options] (e.g. --dir=\"~/src/build\" or --dir=\"~/src/sources:ro\")", discussion: """
   Requires host to be macOS 13.0 (Ventura) or newer. macOS guests must be running macOS 13.0 (Ventura) or newer too.
 
@@ -178,7 +170,7 @@ struct Run: AsyncParsableCommand {
   Mount tag can be overridden by appending tag property to the directory share (e.g. --dir=\"~/src/build:tag=build\" or --dir=\"~/src/build:ro,tag=build\"). Then it can be mounted via "mount_virtiofs build ~/build" inside guest macOS and "mount -t virtiofs build ~/build" inside guest Linux.
 
   In case of passing multiple directories per mount tag it is required to prefix them with names e.g. --dir=\"build:~/src/build\" --dir=\"sources:~/src/sources:ro\". These names will be used as directory names under the mounting point inside guests. For the example above it will be "/Volumes/My Shared Files/build" and "/Volumes/My Shared Files/sources" respectively.
-  """, valueName: "path"), completion: .directory)
+  """, valueName: "[name:]path[:options]"), completion: .directory)
   var dir: [String] = []
 
   @Flag(help: ArgumentHelp("Enable nested virtualization if possible"))
@@ -506,9 +498,9 @@ struct Run: AsyncParsableCommand {
 
         Foundation.exit(0)
       } catch {
-        // Capture the error into Sentry
-        SentrySDK.capture(error: error)
-        SentrySDK.flush(timeout: 2.seconds.timeInterval)
+        // Record the error into OpenTelemetry
+        Telemetry.recordError(error)
+        Telemetry.flush()
 
         fputs("\(error)\n", stderr)
 

Sources/tart/DiskImageFormat.swift

@@ -21,7 +21,7 @@ enum DiskImageFormat: String, CaseIterable, Codable {
     case .raw:
       return true
     case .asif:
-      if #available(macOS 15, *) {
+      if #available(macOS 26, *) {
         return true
       } else {
         return false

Sources/tart/Root.swift

@@ -1,7 +1,7 @@
 import ArgumentParser
 import Darwin
 import Foundation
-import Sentry
+// Telemetry integration is encapsulated in Telemetry.swift
 
 @main
 struct Root: AsyncParsableCommand {
@@ -54,38 +54,9 @@ struct Root: AsyncParsableCommand {
       // Parse command
       var command = try parseAsRoot()
 
-      // Initialize Sentry
-      if let dsn = ProcessInfo.processInfo.environment["SENTRY_DSN"] {
-        SentrySDK.start { options in
-          options.dsn = dsn
-          options.releaseName = CI.release
-          options.tracesSampleRate = Float(
-            ProcessInfo.processInfo.environment["SENTRY_TRACES_SAMPLE_RATE"] ?? "1.0"
-          ) as NSNumber?
-
-          // By default only 5XX are captured
-          // Let's capture everything but 401 (unauthorized)
-          options.enableCaptureFailedRequests = true
-          options.failedRequestStatusCodes = [
-            HttpStatusCodeRange(min: 400, max: 400),
-            HttpStatusCodeRange(min: 402, max: 599)
-          ]
-        }
-      }
-      defer { SentrySDK.flush(timeout: 2.seconds.timeInterval) }
-
-      SentrySDK.configureScope { scope in
-        scope.setExtra(value: ProcessInfo.processInfo.arguments, key: "Command-line arguments")
-      }
-
-      // Enrich future events with Cirrus CI-specific tags
-      if let tags = ProcessInfo.processInfo.environment["CIRRUS_SENTRY_TAGS"] {
-        SentrySDK.configureScope { scope in
-          for (key, value) in tags.split(separator: ",").compactMap({ parseCirrusSentryTag($0) }) {
-            scope.setTag(value: value, key: key)
-          }
-        }
-      }
+      // Initialize OpenTelemetry if configured
+      Telemetry.bootstrapFromEnv()
+      defer { Telemetry.flush() }
 
       // Run garbage-collection before each command (shouldn't take too long)
       if type(of: command) != type(of: Pull()) && type(of: command) != type(of: Clone()){
@@ -108,9 +79,9 @@ struct Root: AsyncParsableCommand {
         Foundation.exit(execCustomExitCodeError.exitCode)
       }
 
-      // Capture the error into Sentry
-      SentrySDK.capture(error: error)
-      SentrySDK.flush(timeout: 2.seconds.timeInterval)
+      // Record the error into OpenTelemetry
+      Telemetry.recordError(error)
+      Telemetry.flush()
 
       // Handle a non-ArgumentParser's exception that requires a specific exit code to be set
       if let errorWithExitCode = error as? HasExitCode {

Sources/tart/ShellCompletions/ShellCompletions.swift

@@ -5,7 +5,7 @@ fileprivate func normalizeName(_ name: String) -> String {
   return name.replacingOccurrences(of: ":", with: "\\:")
 }
 
-func completeMachines(_ arguments: [String]) -> [String] {
+func completeMachines(_ arguments: [String], _ argumentIdx: Int, _ argumentPrefix: String) -> [String] {
   let localVMs = (try? VMStorageLocal().list().map { name, _ in
     normalizeName(name)
   }) ?? []
@@ -15,12 +15,12 @@ func completeMachines(_ arguments: [String]) -> [String] {
   return (localVMs + ociVMs)
 }
 
-func completeLocalMachines(_ arguments: [String]) -> [String] {
+func completeLocalMachines(_ arguments: [String], _ argumentIdx: Int, _ argumentPrefix: String) -> [String] {
   let localVMs = (try? VMStorageLocal().list()) ?? []
   return localVMs.map { name, _ in normalizeName(name) }
 }
 
-func completeRunningMachines(_ arguments: [String]) -> [String] {
+func completeRunningMachines(_ arguments: [String], _ argumentIdx: Int, _ argumentPrefix: String) -> [String] {
   let localVMs = (try? VMStorageLocal().list()) ?? []
   return localVMs
     .filter { _, vmDir in (try? vmDir.state() == .Running) ?? false}

Sources/tart/Telemetry.swift

@@ -0,0 +1,152 @@
+import Foundation
+import OpenTelemetryApi
+import OpenTelemetrySdk
+import OpenTelemetryProtocolExporterCommon
+import OpenTelemetryProtocolExporterGrpc
+import OpenTelemetryProtocolExporterHttp
+import GRPC
+import NIO
+
+enum TelemetrySpanStatus { case cancelled }
+
+final class TelemetrySpan {
+  private let span: Span
+
+  init(_ span: Span) { self.span = span }
+
+  func finish(status: TelemetrySpanStatus? = nil) {
+    if let status = status {
+      switch status {
+      case .cancelled:
+        span.status = .error(description: "cancelled")
+      }
+    }
+    span.end()
+    if Telemetry.currentSpan === span {
+      Telemetry.currentSpan = nil
+    }
+  }
+}
+
+enum Telemetry {
+  static var tracer: Tracer = OpenTelemetry.instance.tracerProvider.get(instrumentationName: "tart", instrumentationVersion: CI.version)
+  static var currentSpan: Span?
+  private static var eventLoopGroup: EventLoopGroup?
+  private static var providerSdk: TracerProviderSdk?
+
+  // Configure OpenTelemetry when OTEL_EXPORTER_OTLP_ENDPOINT is set.
+  static func bootstrapFromEnv() {
+    guard let endpoint = ProcessInfo.processInfo.environment["OTEL_EXPORTER_OTLP_ENDPOINT"], !endpoint.isEmpty else {
+      return
+    }
+
+    let resource = buildResource()
+
+    // Build exporter configuration
+    let headerList = parseHeaders(ProcessInfo.processInfo.environment["OTEL_EXPORTER_OTLP_HEADERS"]) // [(k,v)]
+
+    // Build exporter based on endpoint scheme
+    var exporter: SpanExporter
+    if endpoint.lowercased().hasPrefix("http://") || endpoint.lowercased().hasPrefix("https://") {
+      let url = URL(string: endpoint)!
+      let config = OtlpConfiguration(timeout: 10, headers: headerList, exportAsJson: false)
+      exporter = OtlpHttpTraceExporter(endpoint: url, config: config, envVarHeaders: nil)
+    } else {
+      // gRPC: parse host[:port]
+      let parts = endpoint.split(separator: ":", maxSplits: 1, omittingEmptySubsequences: true)
+      let host = String(parts.first!)
+      let port = parts.count > 1 ? Int(parts[1]) ?? 4317 : 4317
+      let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
+      eventLoopGroup = group
+      let channel = ClientConnection.insecure(group: group).connect(host: host, port: port)
+      let config = OtlpConfiguration(timeout: 10, headers: headerList, exportAsJson: false)
+      exporter = OtlpTraceExporter(channel: channel, config: config, envVarHeaders: nil)
+    }
+
+    let spanProcessor = BatchSpanProcessor(spanExporter: exporter)
+    let provider = TracerProviderBuilder()
+      .add(spanProcessor: spanProcessor)
+      .with(resource: resource)
+      .build()
+
+    providerSdk = provider
+    OpenTelemetry.registerTracerProvider(tracerProvider: provider)
+    tracer = OpenTelemetry.instance.tracerProvider.get(instrumentationName: "tart", instrumentationVersion: CI.version)
+  }
+
+  // Flush spans quickly on shutdown
+  static func flush() {
+    providerSdk?.forceFlush(timeout: 5)
+    if let group = eventLoopGroup {
+      try? group.syncShutdownGracefully()
+      eventLoopGroup = nil
+    }
+  }
+
+  static func startTransaction(name: String, operation: String? = nil, bindToScope: Bool = false) -> TelemetrySpan {
+    let builder = tracer.spanBuilder(spanName: name)
+    if let op = operation {
+      builder.setSpanKind(spanKind: .internal)
+      builder.setAttribute(key: "operation", value: op)
+    }
+    let span = builder.startSpan()
+    if bindToScope {
+      currentSpan = span
+    }
+    return TelemetrySpan(span)
+  }
+
+  static func recordError(_ error: Error) {
+    let span = currentSpan ?? tracer.spanBuilder(spanName: "error").startSpan()
+    span.recordException(error)
+    span.status = .error(description: String(describing: error))
+    if currentSpan == nil {
+      span.end()
+    }
+  }
+
+  static func addEvent(_ name: String, attributes: [String: AttributeValue] = [:]) {
+    currentSpan?.addEvent(name: name, attributes: attributes)
+  }
+
+  static func setAttribute(_ key: String, _ value: AttributeValue) {
+    currentSpan?.setAttribute(key: key, value: value)
+  }
+
+  // Build a Resource with service + environment tags
+  private static func buildResource() -> Resource {
+    var attributes: [String: AttributeValue] = [
+      "service.name": .string("tart"),
+      "service.version": .string(CI.version),
+      "process.command_args": AttributeValue(ProcessInfo.processInfo.arguments)
+    ]
+
+    // Migrate Sentry tags to resource attributes if present
+    if let tags = ProcessInfo.processInfo.environment["CIRRUS_SENTRY_TAGS"] {
+      for (k, v) in parseTags(tags) {
+        attributes[k] = .string(v)
+      }
+    }
+
+    return Resource(attributes: attributes)
+  }
+
+  private static func parseTags(_ raw: String) -> [(String, String)] {
+    raw.split(separator: ",").compactMap { pair in
+      let parts = pair.split(separator: "=", maxSplits: 1)
+      guard parts.count == 2 else { return nil }
+      return (String(parts[0]), String(parts[1]))
+    }
+  }
+
+  private static func parseHeaders(_ raw: String?) -> [(String, String)] {
+    guard let raw = raw else { return [] }
+    var result: [(String, String)] = []
+    for part in raw.split(separator: ",") {
+      let kv = part.split(separator: "=", maxSplits: 1)
+      guard kv.count == 2 else { continue }
+      result.append((String(kv[0]), String(kv[1])))
+    }
+    return result
+  }
+}

Sources/tart/VMDirectory+OCI.swift

@@ -1,6 +1,6 @@
 import Compression
 import Foundation
-import Sentry
+// Telemetry integration is encapsulated in Telemetry.swift
 
 enum OCIError: Error {
   case ShouldBeExactlyOneLayer
@@ -43,7 +43,7 @@ extension VMDirectory {
     }
 
     let diskCompressedSize = layers.map { Int64($0.size) }.reduce(0, +)
-    SentrySDK.span?.setMeasurement(name: "compressed_disk_size", value: diskCompressedSize as NSNumber, unit: MeasurementUnitInformation.byte)
+    Telemetry.setAttribute("compressed_disk_size", .int(Int(diskCompressedSize)))
 
     let prettyDiskSize = String(format: "%.1f", Double(diskCompressedSize) / 1_000_000_000.0)
     defaultLogger.appendNewLine("pulling disk (\(prettyDiskSize) GB compressed)...")

Sources/tart/VMStorageOCI.swift

@@ -1,5 +1,5 @@
 import Foundation
-import Sentry
+// Telemetry integration is encapsulated in Telemetry.swift
 import Retry
 
 class VMStorageOCI: PrunableStorage {
@@ -27,12 +27,12 @@ class VMStorageOCI: PrunableStorage {
     return digest
   }
 
-  func open(_ name: RemoteName) throws -> VMDirectory {
+  func open(_ name: RemoteName, _ accessDate: Date = Date()) throws -> VMDirectory {
     let vmDir = VMDirectory(baseURL: vmURL(name))
 
     try vmDir.validate(userFriendlyName: name.description)
 
-    try vmDir.baseURL.updateAccessDate()
+    try vmDir.baseURL.updateAccessDate(accessDate)
 
     return vmDir
   }
@@ -141,9 +141,10 @@ class VMStorageOCI: PrunableStorage {
   }
 
   func pull(_ name: RemoteName, registry: Registry, concurrency: UInt, deduplicate: Bool) async throws {
-    SentrySDK.configureScope { scope in
-      scope.setContext(value: ["imageName": name.description], key: "OCI")
-    }
+    // Record image name for diagnostics
+    Telemetry.addEvent("OCI.pull.start", attributes: [
+      "imageName": .string(name.description)
+    ])
 
     defaultLogger.appendNewLine("pulling manifest...")
 
@@ -177,18 +178,22 @@ class VMStorageOCI: PrunableStorage {
     }
 
     if !exists(digestName) {
-      let transaction = SentrySDK.startTransaction(name: name.description, operation: "pull", bindToScope: true)
+      let transaction = Telemetry.startTransaction(name: name.description, operation: "pull", bindToScope: true)
       let tmpVMDir = try VMDirectory.temporaryDeterministic(key: name.description)
 
+      // Open an existing VM directory corresponding to this name, if any,
+      // marking it as outdated to speed up the garbage collection process
+      _ = try? open(name, Date(timeIntervalSince1970: 0))
+
       // Lock the temporary VM directory to prevent it's garbage collection
       let tmpVMDirLock = try FileLock(lockURL: tmpVMDir.baseURL)
       try tmpVMDirLock.lock()
 
       // Try to reclaim some cache space if we know the VM size in advance
       if let uncompressedDiskSize = manifest.uncompressedDiskSize() {
-        SentrySDK.configureScope { scope in
-          scope.setContext(value: ["imageUncompressedDiskSize": uncompressedDiskSize], key: "OCI")
-        }
+        Telemetry.addEvent("OCI.pull.uncompressed_size", attributes: [
+          "bytes": .int(Int(uncompressedDiskSize))
+        ])
 
         let otherVMFilesSize: UInt64 = 128 * 1024 * 1024
 
@@ -223,7 +228,7 @@ class VMStorageOCI: PrunableStorage {
         try move(digestName, from: tmpVMDir)
         transaction.finish()
       }, onCancel: {
-        transaction.finish(status: SentrySpanStatus.cancelled)
+        transaction.finish(status: .cancelled)
         try? FileManager.default.removeItem(at: tmpVMDir.baseURL)
       })
     } else {

Tests/TartTests/DiskImageFormatTests.swift

@@ -2,13 +2,9 @@ import XCTest
 @testable import tart
 
 final class DiskImageFormatTests: XCTestCase {
-  func testRawFormatIsAlwaysSupported() throws {
-    XCTAssertTrue(DiskImageFormat.raw.isSupported)
-  }
-
   func testASIFFormatSupport() throws {
-    // ASIF should be supported on macOS 15+
-    if #available(macOS 15, *) {
+    // ASIF should be supported on macOS 26+
+    if #available(macOS 26, *) {
       XCTAssertTrue(DiskImageFormat.asif.isSupported)
     } else {
       XCTAssertFalse(DiskImageFormat.asif.isSupported)

docs/faq.md

@@ -166,6 +166,8 @@ Tart does have an analogue of Anka Controller for managing VMs across a cluster
 
 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.
 
+The `tart clone` command limits this automatic pruning to 100 GB by default to avoid removing too many cached items. You can change this limit with the `--prune-limit` option (in gigabytes).
+
 To disable this functionality, set the `TART_NO_AUTO_PRUNE` environment variable either globally:
 
 ```shell

mkdocs.yml

@@ -46,6 +46,7 @@ plugins:
       match_path: blog/posts/.*
       date_from_meta:
         as_creation: date
+      abstract_chars_count: -1
   - social:
       cards_layout_dir: docs/layouts
       cards_layout: custom