Add table existence checks to migration scripts

backend/migrations/versions/7d27395c892a_new_migration.py

@@ -8,6 +8,7 @@ Create Date: 2023-01-18 14:48:23.996261
 from alembic import op
 import sqlalchemy as sa
 from sqlalchemy.dialects import mysql
+from sqlalchemy.engine.reflection import Inspector
 
 # revision identifiers, used by Alembic.
 revision = '7d27395c892a'
@@ -15,54 +16,62 @@ down_revision = None
 branch_labels = None
 depends_on = None
 
+conn = op.get_bind()
+inspector = Inspector.from_engine(conn)
+tables = inspector.get_table_names()
+
 def upgrade():
-    op.create_table(
-        "app",
-        sa.Column("id", sa.Integer(), nullable=False),
-        sa.Column("name", sa.String(length=64), nullable=True),
-        sa.Column("slug", sa.String(length=64), nullable=True),
-        sa.Column('external', sa.Boolean(), server_default='0', nullable=False),
-        sa.Column('url', sa.String(length=128), nullable=True),
-        sa.PrimaryKeyConstraint("id"),
-        sa.UniqueConstraint("slug"),
-    )
+    if "app" not in tables:
+        op.create_table(
+            "app",
+            sa.Column("id", sa.Integer(), nullable=False),
+            sa.Column("name", sa.String(length=64), nullable=True),
+            sa.Column("slug", sa.String(length=64), nullable=True),
+            sa.Column("external", sa.Boolean(), server_default='0', nullable=False),
+            sa.Column("url", sa.String(length=128), nullable=True),
+            sa.PrimaryKeyConstraint("id"),
+            sa.UniqueConstraint("slug"),
+            keep_existing= True
+        )
 
-    op.create_table(
-        "app_role",
-        sa.Column("user_id", sa.String(length=64), nullable=False),
-        sa.Column("app_id", sa.Integer(), nullable=False),
-        sa.Column("role_id", sa.Integer(), nullable=True),
-        sa.ForeignKeyConstraint(
-            ["app_id"],
-            ["app.id"],
-        ),
-        sa.PrimaryKeyConstraint("user_id", "app_id"),
-    )
+    if "app_role" not in tables:
+        op.create_table(
+            "app_role",
+            sa.Column("user_id", sa.String(length=64), nullable=False),
+            sa.Column("app_id", sa.Integer(), nullable=False),
+            sa.Column("role_id", sa.Integer(), nullable=True),
+            sa.ForeignKeyConstraint(
+                ["app_id"],
+                ["app.id"],
+            ),
+            sa.PrimaryKeyConstraint("user_id", "app_id"),
+        )
 
-    op.create_table(
-        "role",
-        sa.Column("id", sa.Integer(), nullable=False),
-        sa.Column("name", sa.String(length=64), nullable=True),
-        sa.PrimaryKeyConstraint("id"),
-    )
+    if "role" not in tables:
+        op.create_table(
+            "role",
+            sa.Column("id", sa.Integer(), nullable=False),
+            sa.Column("name", sa.String(length=64), nullable=True),
+            sa.PrimaryKeyConstraint("id"),
+        )
+        op.execute("INSERT INTO `role` (id, `name`) VALUES (1, 'admin')")
+        op.execute("INSERT INTO `role` (id, `name`) VALUES (2, 'user')")
+        op.execute("INSERT INTO `role` (id, `name`) VALUES (3, 'no access')")
 
     op.create_foreign_key(None, "app_role", "role", ["role_id"], ["id"])
 
-    op.execute("INSERT INTO `role` (id, `name`) VALUES (1, 'admin')")
-    op.execute("INSERT INTO `role` (id, `name`) VALUES (2, 'user')")
-    op.execute("INSERT INTO `role` (id, `name`) VALUES (3, 'no access')")
-
-    op.create_table('oauthclient_app',
-        sa.Column('oauthclient_id', mysql.VARCHAR(length=64), nullable=False),
-        sa.Column('app_id', mysql.INTEGER(display_width=11), autoincrement=False, nullable=False),
-        sa.ForeignKeyConstraint(['app_id'], ['app.id'], name='oauthclient_app_fk_app_id'),
-        sa.PrimaryKeyConstraint('oauthclient_id'),
-        mysql_default_charset='utf8mb3',
-        mysql_engine='InnoDB'
-    )
+    if "oauthclient_app" not in tables:
+        op.create_table('oauthclient_app',
+            sa.Column('oauthclient_id', mysql.VARCHAR(length=64), nullable=False),
+            sa.Column('app_id', mysql.INTEGER(display_width=11), autoincrement=False, nullable=False),
+            sa.ForeignKeyConstraint(['app_id'], ['app.id'], name='oauthclient_app_fk_app_id'),
+            sa.PrimaryKeyConstraint('oauthclient_id'),
+            mysql_default_charset='utf8mb3',
+            mysql_engine='InnoDB'
+        )
 
 def downgrade():
     op.drop_table("role")
     op.drop_table("app_role")
     op.drop_table("app")
-    op.drop_table('oauthclient_app')
+    op.drop_table("oauthclient_app")