fix(print): copies-Replikation erzeugt UNIQUE job_ids (Round 2 #hangar-109)

[strausmann]

Akuter User-Bug-Report 2026-06-14

User druckte nach PR #115-Deploy SMA-022-003 mit Menge 3 — erneut nur 1 Etikett.

Root Cause

PR #115 hat das Image N-mal mit DERSELBEN job_id eingereiht. Live-Logs vom Hub:

Batch 7d8470f4-3b3d-4a20-ac6c-c87f493e41a3: job 711db9bc-61bb-4eed-9a87-03aa5c0d4467 skipped — state already printing (cancelled?)
Batch 7d8470f4-3b3d-4a20-ac6c-c87f493e41a3: job 711db9bc-61bb-4eed-9a87-03aa5c0d4467 skipped — state already printing (cancelled?)

PrintQueue.BatchWorker (Z.858-880) macht für jeden batch.job_ids ein JobStateMachine.transition(job, PRINTING). Der zweite Aufruf mit demselben job_id scheitert mit InvalidStateTransitionError (Job bereits PRINTING), das Image wird übersprungen.

Resultat: 1 active_payload → 1 Etikett. Mein PR #115 Test war ebenfalls falsch — er asserierte explizit len(set(job_ids)) == 1 und hat den Bug damit zementiert.

Fix

print_service.py:submit_batch_job erzeugt jetzt:

• Pro Request × pro Copy einen eigenen DB-Job mit eindeutiger UUID
• copy_index / copy_total / copy_master_id als Payload-Metadata (Audit)
• BatchWorker kann jeden Druck unabhängig transitionen → keine Skips mehr

API-Vertrag bleibt für Hangar

submit_batch_job returniert weiterhin 1 master_id pro Request (1:1 zur Hangar-Bestellung), nicht 1:N. Hangar muss nichts ändern.

Tests

TestSubmitBatchJobCopies korrigiert:

Vorher (falsch, hat den Bug zementiert)	Nachher (Bug-Verhinderung)
assert len(set(job_ids)) == 1	assert len(set(job_ids)) == 3
assert len(set(job_ids)) == 2 (mixed)	assert len(set(job_ids)) == 3

Zusätzlich Sicherstellung dass master_ids weiterhin 1 pro Request bleibt.

$ pytest tests/unit/services/test_print_service.py
16 passed in 0.48s

mypy ✓ ruff check ✓ ruff format ✓

Folge-Action

User soll nach Deploy SMA-022-003 mit Menge 3 erneut drucken → erwarte 3 Etiketten via Half-Cut.

Refs Hangar Issue #109, korrigiert PR #115

[Copilot]

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[gemini-code-assist]

Summary of Changes

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Dieser Pull Request behebt einen kritischen Fehler beim Drucken von Etiketten mit einer Kopienanzahl größer als eins. Zuvor wurden alle Kopien mit derselben Job-ID eingereiht, was dazu führte, dass der BatchWorker die nachfolgenden Kopien als bereits in Bearbeitung befindlich markierte und übersprang. Durch die Zuweisung eindeutiger UUIDs pro Kopie wird sichergestellt, dass der Worker jeden Druckvorgang korrekt verarbeiten kann, ohne die externe API-Schnittstelle zu verändern.

Highlights

• Fix für Duplikats-Druckfehler: Jede Kopie eines Druckauftrags erhält nun eine eindeutige UUID, um zu verhindern, dass der BatchWorker nachfolgende Kopien aufgrund von Zustandsübergangskonflikten überspringt.
• API-Kompatibilität: Die API gibt weiterhin eine Master-ID pro Anfrage zurück, um die Kompatibilität mit Hangar zu wahren, während intern alle Kopien für Audit-Zwecke einzeln persistiert werden.
• Test-Anpassungen: Die Unit-Tests wurden korrigiert, um sicherzustellen, dass bei mehreren Kopien tatsächlich eindeutige Job-IDs erzeugt werden, anstatt die fehlerhafte Logik zu zementieren.

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[gemini-code-assist]

Code Review

This pull request resolves an issue where enqueuing multiple copies of a print job with the same job ID caused state transition failures in the batch worker. The fix generates a unique UUID for each copy while retaining a master ID reference for the API, and persists each copy independently in the database. The unit tests have been updated to verify this behavior. Feedback on the changes suggests optimizing database persistence by saving the job records concurrently using asyncio.gather instead of sequentially inside the nested loop.

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[gemini-code-assist]

Awaiting self._store.save_queued(db_job) sequentially inside a nested loop can introduce significant latency, especially when printing multiple copies or processing large batches. Since the JobStore protocol guarantees that implementations are safe for concurrent calls from multiple asyncio tasks, we can collect all the save coroutines and execute them concurrently using asyncio.gather to improve performance.

        job_ids: list[UUID] = []  # master IDs, 1 pro request — Hangar-API
        all_job_ids: list[UUID] = []  # alle inkl. Copies — für enqueue_batch
        images: list[Image.Image] = []
        save_tasks = []
        for request, (img, ld_dump) in zip(requests, prepared, strict=True):
            n = max(1, int(request.options.copies))
            master_id = uuid4()
            job_ids.append(master_id)
            for copy_idx in range(n):
                this_id = master_id if copy_idx == 0 else uuid4()
                db_job = Job(
                    id=this_id,
                    printer_id=self._printer_id,
                    template_key=None,
                    payload={
                        "tape_mm": tape_mm,
                        "content_type": str(request.content_type),
                        "rendered_tape_mm": tape_mm,
                        "options": request.options.model_dump(),
                        "label_data": ld_dump,
                        "copy_index": copy_idx,
                        "copy_total": n,
                        "copy_master_id": str(master_id),
                    },
                    api_key_id=None,
                    source_ip=None,
                )
                save_tasks.append(self._store.save_queued(db_job))
                images.append(img)
                all_job_ids.append(this_id)

        await asyncio.gather(*save_tasks)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.33%. Comparing base (ab8c4c4) to head (92b9f97).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #120      +/-   ##
==========================================
+ Coverage   89.26%   89.33%   +0.07%     
==========================================
  Files          91       91              
  Lines        4257     4257              
  Branches      369      368       -1     
==========================================
+ Hits         3800     3803       +3     
+ Misses        359      355       -4     
- Partials       98       99       +1     

Components	Coverage Δ
Printer Backends (transport)	86.87% <ø> (ø)
Printer Models (drivers)	88.20% <ø> (ø)
Services	91.20% <100.00%> (-0.07%)	⬇️
REST API	85.23% <ø> (+0.25%)	⬆️
Pydantic Schemas	100.00% <ø> (ø)
Integration Plugins	100.00% <ø> (ø)

Files with missing lines	Coverage Δ
backend/app/services/print_service.py	89.70% <100.00%> (ø)

... and 3 files with indirect coverage changes

Flag	Coverage Δ
backend	89.33% <100.00%> (+0.07%)	⬆️

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