Initial commit

migrations/tenant/env.py

@@ -0,0 +1,124 @@
+import logging
+from logging.config import fileConfig
+
+from flask import current_app
+
+from alembic import context
+
+from eveai_app.models.user import Tenant
+
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+fileConfig(config.config_file_name)
+logger = logging.getLogger('alembic.env')
+
+
+def get_engine():
+    try:
+        # this works with Flask-SQLAlchemy<3 and Alchemical
+        return current_app.extensions['migrate'].db.get_engine()
+    except (TypeError, AttributeError):
+        # this works with Flask-SQLAlchemy>=3
+        return current_app.extensions['migrate'].db.engine
+
+
+def get_engine_url():
+    try:
+        return get_engine().url.render_as_string(hide_password=False).replace(
+            '%', '%%')
+    except AttributeError:
+        return str(get_engine().url).replace('%', '%%')
+
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+config.set_main_option('sqlalchemy.url', get_engine_url())
+target_db = current_app.extensions['migrate'].db
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+# List of Tenants
+tenants = [tenant.id for tenant in Tenant.query.all()]
+
+
+def get_metadata():
+    if hasattr(target_db, 'metadatas'):
+        return target_db.metadatas[None]
+    return target_db.metadata
+
+
+def run_migrations_offline():
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url, target_metadata=get_metadata(), literal_binds=True
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online():
+    """Updated migration script for handling schema based multi-tenancy
+
+    ref:
+     - https://alembic.sqlalchemy.org/en/latest/cookbook.html#rudimental-schema-level-multi-tenancy-for-postgresql-databases # noqa
+    """
+
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section),
+        prefix="sqlalchemy.",
+        poolclass=NullPool,
+    )
+
+    with connectable.connect() as connection:
+        for tenant in tenants:
+            logger.info(f"Migrating tenant: {tenant}")
+            # set search path on the connection, which ensures that
+            # PostgreSQL will emit all CREATE / ALTER / DROP statements
+            # in terms of this schema by default
+            connection.execute(text(f'SET search_path TO "{tenant}"'))
+            # in SQLAlchemy v2+ the search path change needs to be committed
+            # connection.commit()
+
+            # make use of non-supported SQLAlchemy attribute to ensure
+            # the dialect reflects tables in terms of the current tenant name
+            connection.dialect.default_schema_name = tenant
+
+            context.configure(
+                connection=connection,
+                target_metadata=get_metadata(),
+            )
+
+            with context.begin_transaction():
+                context.run_migrations()
+
+            # for checking migrate or upgrade is running
+            if getattr(config.cmd_opts, "autogenerate", False):
+                break
+
+
+if context.is_offline_mode():
+    raise Exception("Offline migrations are not supported")
+else:
+    run_migrations_online()