ArchiveBox/ArchiveBox · error · ExceptionGroup

One or more snapshot tasks failed

Error message

One or more snapshot tasks failed

What it means

wait_for_snapshot_tasks collects exceptions from concurrently running snapshot asyncio tasks; if all tasks finished and errors remain, it re-raises the single error directly, or wraps multiple in an ExceptionGroup with this message. It signals that one or more snapshots in the crawl failed rather than swallowing their errors.

Source

Thrown at archivebox/services/runner.py:449

                if task.done():
                    if self.snapshot_tasks.get(snapshot_id) is task:
                        self.snapshot_tasks.pop(snapshot_id, None)
                    try:
                        task.result()
                    except asyncio.CancelledError as err:
                        if _is_external_task_cancelled(err):
                            raise
                        stop_scheduling = True
                    except Exception as err:
                        task_errors.append(err)
                        stop_scheduling = True
                    continue
                pending_tasks.append(task)
            if not pending_tasks:
                if task_errors:
                    if len(task_errors) == 1:
                        raise task_errors[0]
                    raise ExceptionGroup("One or more snapshot tasks failed", task_errors)
                if stop_scheduling:
                    return
                await self.enqueue_pending_snapshots_from_projection()
                if not self.snapshot_tasks:
                    return
                continue
            await self.heartbeat_active_leases()
            done, _pending = await asyncio.wait(pending_tasks, timeout=10.0, return_when=asyncio.FIRST_COMPLETED)
            if not done:
                continue
            for task in done:
                for snapshot_id, tracked_task in list(self.snapshot_tasks.items()):
                    if tracked_task is task:
                        self.snapshot_tasks.pop(snapshot_id, None)
                        break
                try:
                    task.result()
                except asyncio.CancelledError as err:

View on GitHub (pinned to 74564b2822)

Solutions

1. Unwrap the ExceptionGroup and inspect each sub-exception (Python 3.11 except* or .exceptions) to find which snapshots failed
2. Fix the underlying per-snapshot failures (plugin errors, network, DB) and re-run the crawl
3. Enable verbose logging for the runner to get per-task stack traces before aggregation

Example fix

// before
try:
    await runner.wait_for_snapshot_tasks()
except Exception as e:
    print(e)
// after
try:
    await runner.wait_for_snapshot_tasks()
except* Exception as eg:
    for sub in eg.exceptions:
        log(sub)

try:
    await runner.wait_for_snapshot_tasks()
except* Exception as eg:
    for sub in eg.exceptions:
        logger.error('snapshot task failed: %r', sub)
# single-error case surfaces directly (not wrapped)

When it happens

Trigger: During a crawl (on_archivebox_CrawlStartEvent) snapshot tasks raise exceptions (plugin crashes, DB errors, subprocess failures); when no pending tasks remain, the aggregated errors are raised as an ExceptionGroup.

Common situations: Crawl 0.7+ runs where several extraction plugins fail; transient network failures across multiple snapshot tasks; inspecting why a crawl reported failure and needing to see all sub-errors.

Related errors

• Crawl setup hook {plugin.name}:{hook.name} did not start
• Crawl setup hook {plugin.name}:{hook.name} did not complete
• Snapshot events must be emitted from a CrawlStartEvent handl
• Snapshot {snapshot_id} did not complete

AI-assisted analysis of ArchiveBox/ArchiveBox@74564b2822 (2026-08-28). Data as JSON: /api/errors/86e7cb5e9187dbf6. Report an issue: GitHub.