新增PDF生成并发设置

backend/alembic/versions/20260623_0004_system_settings.py

@@ -0,0 +1,49 @@
+"""add system settings
+
+Revision ID: 20260623_0004
+Revises: 20260609_0003
+Create Date: 2026-06-23
+"""
+
+from datetime import datetime
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+revision: str = "20260623_0004"
+down_revision: Union[str, None] = "20260609_0003"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "system_settings",
+        sa.Column("key", sa.String(length=128), nullable=False),
+        sa.Column("value", sa.Text(), nullable=False),
+        sa.Column("description", sa.String(length=255), nullable=True),
+        sa.Column("updated_at", sa.DateTime(), nullable=False),
+        sa.PrimaryKeyConstraint("key"),
+    )
+    op.bulk_insert(
+        sa.table(
+            "system_settings",
+            sa.column("key", sa.String),
+            sa.column("value", sa.Text),
+            sa.column("description", sa.String),
+            sa.column("updated_at", sa.DateTime),
+        ),
+        [
+            {
+                "key": "pdf_generation_concurrency_limit",
+                "value": "2",
+                "description": "PDF证书同时生成数量限制",
+                "updated_at": datetime.utcnow(),
+            }
+        ],
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("system_settings")