fix: replace flaky internet checks with explicit offline mode

Remove socket-based internet connectivity probes (1.1.1.1/8.8.8.8 every
10s) that caused false negatives. Replace with an explicit offline mode
toggled via --offline CLI flag, EXO_OFFLINE env var, or macOS app settings.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: AlexCheema

app/EXO/EXO/ExoProcessController.swift

@@ -5,6 +5,7 @@ import Foundation
 private let customNamespaceKey = "EXOCustomNamespace"
 private let hfTokenKey = "EXOHFToken"
 private let enableImageModelsKey = "EXOEnableImageModels"
+private let offlineModeKey = "EXOOfflineMode"
 private let onboardingCompletedKey = "EXOOnboardingCompleted"
 
 @MainActor
@@ -60,6 +61,14 @@ final class ExoProcessController: ObservableObject {
             UserDefaults.standard.set(enableImageModels, forKey: enableImageModelsKey)
         }
     }
+    @Published var offlineMode: Bool = {
+        return UserDefaults.standard.bool(forKey: offlineModeKey)
+    }()
+    {
+        didSet {
+            UserDefaults.standard.set(offlineMode, forKey: offlineModeKey)
+        }
+    }
 
     /// Fires once when EXO transitions to `.running` for the very first time (fresh install).
     @Published private(set) var isFirstLaunchReady = false
@@ -267,6 +276,9 @@ final class ExoProcessController: ObservableObject {
         if enableImageModels {
             environment["EXO_ENABLE_IMAGE_MODELS"] = "true"
         }
+        if offlineMode {
+            environment["EXO_OFFLINE"] = "true"
+        }
 
         var paths: [String] = []
         if let existing = environment["PATH"], !existing.isEmpty {

app/EXO/EXO/Views/SettingsView.swift

@@ -13,6 +13,7 @@ struct SettingsView: View {
     @State private var pendingNamespace: String = ""
     @State private var pendingHFToken: String = ""
     @State private var pendingEnableImageModels = false
+    @State private var pendingOfflineMode = false
     @State private var needsRestart = false
     @State private var bugReportInFlight = false
     @State private var bugReportMessage: String?
@@ -42,6 +43,7 @@ struct SettingsView: View {
             pendingNamespace = controller.customNamespace
             pendingHFToken = controller.hfToken
             pendingEnableImageModels = controller.enableImageModels
+            pendingOfflineMode = controller.offlineMode
             needsRestart = false
         }
     }
@@ -72,6 +74,13 @@ struct SettingsView: View {
                     .foregroundColor(.secondary)
             }
 
+            Section {
+                Toggle("Offline Mode", isOn: $pendingOfflineMode)
+                Text("Skip internet checks and use only locally available models.")
+                    .font(.caption)
+                    .foregroundColor(.secondary)
+            }
+
             Section {
                 HStack {
                     Spacer()
@@ -445,6 +454,7 @@ struct SettingsView: View {
 
     private var hasGeneralChanges: Bool {
         pendingNamespace != controller.customNamespace || pendingHFToken != controller.hfToken
+            || pendingOfflineMode != controller.offlineMode
     }
 
     private var hasModelChanges: Bool {
@@ -454,6 +464,7 @@ struct SettingsView: View {
     private func applyGeneralSettings() {
         controller.customNamespace = pendingNamespace
         controller.hfToken = pendingHFToken
+        controller.offlineMode = pendingOfflineMode
         restartIfRunning()
     }
 

src/exo/download/coordinator.py

@@ -1,5 +1,4 @@
 import asyncio
-import socket
 from dataclasses import dataclass, field
 from random import random
 
@@ -73,8 +72,6 @@ class DownloadCoordinator:
 
     def __post_init__(self) -> None:
         self.event_sender, self.event_receiver = channel[Event]()
-        if self.offline:
-            self.shard_downloader.set_internet_connection(False)
         self.shard_downloader.on_progress(self._download_progress_callback)
 
     def _model_dir(self, model_id: ModelId) -> str:
@@ -123,49 +120,17 @@ async def run(self) -> None:
         logger.info(
             f"Starting DownloadCoordinator{' (offline mode)' if self.offline else ''}"
         )
-        if not self.offline:
-            self._test_internet_connection()
         try:
             async with self._tg as tg:
                 tg.start_soon(self._command_processor)
                 tg.start_soon(self._forward_events)
                 tg.start_soon(self._emit_existing_download_progress)
                 tg.start_soon(self._resend_out_for_delivery)
                 tg.start_soon(self._clear_ofd)
-                if not self.offline:
-                    tg.start_soon(self._check_internet_connection)
         finally:
             for task in self.active_downloads.values():
                 task.cancel()
 
-    def _test_internet_connection(self) -> None:
-        # Try multiple endpoints since some ISPs/networks block specific IPs
-        for host in ("1.1.1.1", "8.8.8.8", "1.0.0.1"):
-            try:
-                socket.create_connection((host, 443), timeout=3).close()
-                self.shard_downloader.set_internet_connection(True)
-                logger.debug(f"Internet connectivity: True (via {host})")
-                return
-            except OSError:
-                continue
-        self.shard_downloader.set_internet_connection(False)
-        logger.debug("Internet connectivity: False")
-
-    async def _check_internet_connection(self) -> None:
-        first_connection = True
-        while True:
-            await asyncio.sleep(10)
-
-            # Assume that internet connection is set to False on 443 errors.
-            if self.shard_downloader.internet_connection:
-                continue
-
-            self._test_internet_connection()
-
-            if first_connection and self.shard_downloader.internet_connection:
-                first_connection = False
-                self._tg.start_soon(self._emit_existing_download_progress)
-
     def shutdown(self) -> None:
         self._tg.cancel_tasks()
 

src/exo/download/impl_shard_downloader.py

@@ -15,9 +15,13 @@
 )
 
 
-def exo_shard_downloader(max_parallel_downloads: int = 8) -> ShardDownloader:
+def exo_shard_downloader(
+    max_parallel_downloads: int = 8, offline: bool = False
+) -> ShardDownloader:
     return SingletonShardDownloader(
-        CachedShardDownloader(ResumableShardDownloader(max_parallel_downloads))
+        CachedShardDownloader(
+            ResumableShardDownloader(max_parallel_downloads, offline=offline)
+        )
     )
 
 
@@ -50,10 +54,6 @@ def __init__(self, shard_downloader: ShardDownloader):
         self.shard_downloader = shard_downloader
         self.active_downloads: dict[ShardMetadata, asyncio.Task[Path]] = {}
 
-    def set_internet_connection(self, value: bool) -> None:
-        self.internet_connection = value
-        self.shard_downloader.set_internet_connection(value)
-
     def on_progress(
         self,
         callback: Callable[[ShardMetadata, RepoDownloadProgress], Awaitable[None]],
@@ -90,10 +90,6 @@ def __init__(self, shard_downloader: ShardDownloader):
         self.shard_downloader = shard_downloader
         self.cache: dict[tuple[str, ShardMetadata], Path] = {}
 
-    def set_internet_connection(self, value: bool) -> None:
-        self.internet_connection = value
-        self.shard_downloader.set_internet_connection(value)
-
     def on_progress(
         self,
         callback: Callable[[ShardMetadata, RepoDownloadProgress], Awaitable[None]],
@@ -123,8 +119,9 @@ async def get_shard_download_status_for_shard(
 
 
 class ResumableShardDownloader(ShardDownloader):
-    def __init__(self, max_parallel_downloads: int = 8):
+    def __init__(self, max_parallel_downloads: int = 8, offline: bool = False):
         self.max_parallel_downloads = max_parallel_downloads
+        self.offline = offline
         self.on_progress_callbacks: list[
             Callable[[ShardMetadata, RepoDownloadProgress], Awaitable[None]]
         ] = []
@@ -151,8 +148,7 @@ async def ensure_shard(
             self.on_progress_wrapper,
             max_parallel_downloads=self.max_parallel_downloads,
             allow_patterns=allow_patterns,
-            skip_internet=not self.internet_connection,
-            on_connection_lost=lambda: self.set_internet_connection(False),
+            skip_internet=self.offline,
         )
         return target_dir
 
@@ -168,8 +164,7 @@ async def _status_for_model(
                 shard,
                 self.on_progress_wrapper,
                 skip_download=True,
-                skip_internet=not self.internet_connection,
-                on_connection_lost=lambda: self.set_internet_connection(False),
+                skip_internet=self.offline,
             )
 
         semaphore = asyncio.Semaphore(self.max_parallel_downloads)
@@ -198,7 +193,6 @@ async def get_shard_download_status_for_shard(
             shard,
             self.on_progress_wrapper,
             skip_download=True,
-            skip_internet=not self.internet_connection,
-            on_connection_lost=lambda: self.set_internet_connection(False),
+            skip_internet=self.offline,
         )
         return progress

src/exo/download/shard_downloader.py

@@ -16,11 +16,6 @@
 
 # TODO: the PipelineShardMetadata getting reinstantiated is a bit messy. Should this be a classmethod?
 class ShardDownloader(ABC):
-    internet_connection: bool = False
-
-    def set_internet_connection(self, value: bool) -> None:
-        self.internet_connection = value
-
     @abstractmethod
     async def ensure_shard(
         self, shard: ShardMetadata, config_only: bool = False

src/exo/main.py

@@ -60,7 +60,7 @@ async def create(cls, args: "Args") -> Self:
             download_coordinator = DownloadCoordinator(
                 node_id,
                 session_id,
-                exo_shard_downloader(),
+                exo_shard_downloader(offline=args.offline),
                 download_command_receiver=router.receiver(topics.DOWNLOAD_COMMANDS),
                 local_event_sender=router.sender(topics.LOCAL_EVENTS),
                 offline=args.offline,
@@ -211,7 +211,7 @@ async def _elect_loop(self):
                         self.download_coordinator = DownloadCoordinator(
                             self.node_id,
                             result.session_id,
-                            exo_shard_downloader(),
+                            exo_shard_downloader(offline=self.offline),
                             download_command_receiver=self.router.receiver(
                                 topics.DOWNLOAD_COMMANDS
                             ),
@@ -283,7 +283,7 @@ class Args(CamelCaseModel):
     tb_only: bool = False
     no_worker: bool = False
     no_downloads: bool = False
-    offline: bool = False
+    offline: bool = os.getenv("EXO_OFFLINE", "false").lower() == "true"
     fast_synch: bool | None = None  # None = auto, True = force on, False = force off
 
     @classmethod

src/exo/shared/constants.py

@@ -78,4 +78,6 @@ def _get_xdg_dir(env_var: str, fallback: str) -> Path:
     os.getenv("EXO_ENABLE_IMAGE_MODELS", "false").lower() == "true"
 )
 
+EXO_OFFLINE = os.getenv("EXO_OFFLINE", "false").lower() == "true"
+
 EXO_TRACING_ENABLED = os.getenv("EXO_TRACING_ENABLED", "false").lower() == "true"