feat: aerich.Command support async with syntax (#427)

* feat: `aerich.Command` support `async with` syntax

* docs: update readme

README.md

@@ -226,14 +226,14 @@ from tortoise import Model, fields
 
 
 class Test(Model):
-    date = fields.DateField(null=True, )
+    date = fields.DateField(null=True)
-    datetime = fields.DatetimeField(auto_now=True, )
+    datetime = fields.DatetimeField(auto_now=True)
-    decimal = fields.DecimalField(max_digits=10, decimal_places=2, )
+    decimal = fields.DecimalField(max_digits=10, decimal_places=2)
-    float = fields.FloatField(null=True, )
+    float = fields.FloatField(null=True)
-    id = fields.IntField(pk=True, )
+    id = fields.IntField(primary_key=True)
-    string = fields.CharField(max_length=200, null=True, )
+    string = fields.CharField(max_length=200, null=True)
-    time = fields.TimeField(null=True, )
+    time = fields.TimeField(null=True)
-    tinyint = fields.BooleanField(null=True, )
+    tinyint = fields.BooleanField(null=True)
 ```
 
 Note that this command is limited and can't infer some fields, such as `IntEnumField`, `ForeignKeyField`, and others.
@@ -243,8 +243,8 @@ Note that this command is limited and can't infer some fields, such as `IntEnumF
 ```python
 tortoise_orm = {
     "connections": {
-        "default": expand_db_url(db_url, True),
+        "default": "postgres://postgres_user:postgres_pass@127.0.0.1:5432/db1",
-        "second": expand_db_url(db_url_second, True),
+        "second": "postgres://postgres_user:postgres_pass@127.0.0.1:5432/db2",
     },
     "apps": {
         "models": {"models": ["tests.models", "aerich.models"], "default_connection": "default"},
@@ -253,7 +253,7 @@ tortoise_orm = {
 }
 ```
 
-You only need to specify `aerich.models` in one app, and must specify `--app` when running `aerich migrate` and so on.
+You only need to specify `aerich.models` in one app, and must specify `--app` when running `aerich migrate` and so on, e.g. `aerich --app models_second migrate`.
 
 ## Restore `aerich` workflow
 
@@ -273,9 +273,9 @@ You can use `aerich` out of cli by use `Command` class.
 ```python
 from aerich import Command
 
-command = Command(tortoise_config=config, app='models')
+async with Command(tortoise_config=config, app='models') as command:
-await command.init()
     await command.migrate('test')
+    await command.upgrade()
 ```
 
 ## Upgrade/Downgrade with `--fake` option

aerich/__init__.py

@@ -2,11 +2,12 @@ from __future__ import annotations
 
 import os
 import platform
+from contextlib import AbstractAsyncContextManager
 from pathlib import Path
 from typing import TYPE_CHECKING
 
 import tortoise
-from tortoise import Tortoise, generate_schema_for_client
+from tortoise import Tortoise, connections, generate_schema_for_client
 from tortoise.exceptions import OperationalError
 from tortoise.transactions import in_transaction
 from tortoise.utils import get_schema_sql
@@ -59,10 +60,9 @@ def _init_tortoise_0_24_1_patch():
     from tortoise.backends.base.schema_generator import BaseSchemaGenerator, cast, re
 
     def _get_m2m_tables(
-        self, model: type[Model], table_name: str, safe: bool, models_tables: list[str]
+        self, model: type[Model], db_table: str, safe: bool, models_tables: list[str]
-    ) -> list[str]:
+    ) -> list[str]:  # Copied from tortoise-orm
         m2m_tables_for_create = []
-        db_table = table_name
         for m2m_field in model._meta.m2m_fields:
             field_object = cast("ManyToManyFieldInstance", model._meta.fields_map[m2m_field])
             if field_object._generated or field_object.through in models_tables:
@@ -88,15 +88,15 @@ def _init_tortoise_0_24_1_patch():
             else:
                 backward_fk = forward_fk = ""
             exists = "IF NOT EXISTS " if safe else ""
-            table_name = field_object.through
+            through_table_name = field_object.through
             backward_type = self._get_pk_field_sql_type(model._meta.pk)
             forward_type = self._get_pk_field_sql_type(field_object.related_model._meta.pk)
             comment = ""
             if desc := field_object.description:
-                comment = self._table_comment_generator(table=table_name, comment=desc)
+                comment = self._table_comment_generator(table=through_table_name, comment=desc)
             m2m_create_string = self.M2M_TABLE_TEMPLATE.format(
                 exists=exists,
-                table_name=table_name,
+                table_name=through_table_name,
                 backward_fk=backward_fk,
                 forward_fk=forward_fk,
                 backward_key=backward_key,
@@ -116,7 +116,7 @@ def _init_tortoise_0_24_1_patch():
             m2m_create_string += self._post_table_hook()
             if field_object.create_unique_index:
                 unique_index_create_sql = self._get_unique_index_sql(
-                    exists, table_name, [backward_key, forward_key]
+                    exists, through_table_name, [backward_key, forward_key]
                 )
                 if unique_index_create_sql.endswith(";"):
                     m2m_create_string += "\n" + unique_index_create_sql
@@ -136,7 +136,7 @@ _init_asyncio_patch()
 _init_tortoise_0_24_1_patch()
 
 
-class Command:
+class Command(AbstractAsyncContextManager):
     def __init__(
         self,
         tortoise_config: dict,
@@ -151,6 +151,16 @@ class Command:
     async def init(self) -> None:
         await Migrate.init(self.tortoise_config, self.app, self.location)
 
+    async def __aenter__(self) -> Command:
+        await self.init()
+        return self
+
+    async def close(self) -> None:
+        await connections.close_all()
+
+    async def __aexit__(self, *args, **kw) -> None:
+        await self.close()
+
     async def _upgrade(self, conn, version_file, fake: bool = False) -> None:
         file_path = Path(Migrate.migrate_location, version_file)
         m = import_py_file(file_path)

tests/test_command.py

@@ -0,0 +1,11 @@
+from aerich import Command
+from conftest import tortoise_orm
+
+
+async def test_command(mocker):
+    mocker.patch("os.listdir", return_value=[])
+    async with Command(tortoise_orm) as command:
+        history = await command.history()
+        heads = await command.heads()
+    assert history == []
+    assert heads == []