新增PDF生成并发设置

backend/app/services/system_settings.py

@@ -0,0 +1,64 @@
+from datetime import datetime
+
+from sqlalchemy.orm import Session
+
+from app.models import SystemSetting
+
+PDF_GENERATION_CONCURRENCY_KEY = "pdf_generation_concurrency_limit"
+DEFAULT_PDF_GENERATION_CONCURRENCY = 2
+MIN_PDF_GENERATION_CONCURRENCY = 1
+MAX_PDF_GENERATION_CONCURRENCY = 10
+
+
+def ensure_default_settings(db: Session) -> None:
+    if not db.get(SystemSetting, PDF_GENERATION_CONCURRENCY_KEY):
+        db.add(
+            SystemSetting(
+                key=PDF_GENERATION_CONCURRENCY_KEY,
+                value=str(DEFAULT_PDF_GENERATION_CONCURRENCY),
+                description="PDF证书同时生成数量限制",
+            )
+        )
+
+
+def get_pdf_generation_concurrency_limit(db: Session) -> int:
+    setting = db.get(SystemSetting, PDF_GENERATION_CONCURRENCY_KEY)
+    return _coerce_limit(setting.value if setting else None)
+
+
+def get_pdf_settings(db: Session) -> dict[str, object]:
+    ensure_default_settings(db)
+    setting = db.get(SystemSetting, PDF_GENERATION_CONCURRENCY_KEY)
+    return {
+        "pdf_generation_concurrency_limit": get_pdf_generation_concurrency_limit(db),
+        "updated_at": setting.updated_at if setting else None,
+    }
+
+
+def update_pdf_generation_concurrency_limit(db: Session, value: int) -> dict[str, object]:
+    limit = _coerce_limit(value)
+    ensure_default_settings(db)
+    setting = db.get(SystemSetting, PDF_GENERATION_CONCURRENCY_KEY)
+    if setting is None:
+        setting = SystemSetting(
+            key=PDF_GENERATION_CONCURRENCY_KEY,
+            value=str(limit),
+            description="PDF证书同时生成数量限制",
+        )
+        db.add(setting)
+    else:
+        setting.value = str(limit)
+        setting.updated_at = datetime.utcnow()
+    db.flush()
+    return {
+        "pdf_generation_concurrency_limit": limit,
+        "updated_at": setting.updated_at,
+    }
+
+
+def _coerce_limit(value: object) -> int:
+    try:
+        limit = int(value)
+    except (TypeError, ValueError):
+        limit = DEFAULT_PDF_GENERATION_CONCURRENCY
+    return max(MIN_PDF_GENERATION_CONCURRENCY, min(MAX_PDF_GENERATION_CONCURRENCY, limit))