Alembic sqlalchemy迁移助手不跟踪现有表格

Question

我正在尝试设置alembic来自动生成迁移。目前，当我运行这行代码时：alembic revision --autogenerate -m 'add column' alembic检查spatial_ref_sys中的更改，我已将其忽略，然后创建一个空升级和降级定义的版本文件。它无法识别我对数据库中其他表的更改。我认为我如何定义target_metadata存在问题。我尝试打印Base.metadata.tables并得到immutabledict({})，而当我在我的应用程序中打印相同的东西时，我从我创建的所有表中得到了很长的打印。

alembic.ini

# A generic, single database configuration.

[alembic]
# path to migration scripts
script_location = alembic

# template used to generate migration files
file_template = %%(rev)s_%%(slug)s

# timezone to use when rendering the date
# within the migration file as well as the filename.
# string value is passed to dateutil.tz.gettz()
# leave blank for localtime
timezone = UTC

# max length of characters to apply to the
# "slug" field
truncate_slug_length = 40

# set to 'true' to run the environment during
# the 'revision' command, regardless of autogenerate
revision_environment = false

# set to 'true' to allow .pyc and .pyo files without
# a source .py file to be detected as revisions in the
# versions/ directory
sourceless = false

# version location specification; this defaults
# to alembic/versions.  When using multiple version
# directories, initial revisions must be specified with --version-path
# version_locations = %(here)s/bar %(here)s/bat alembic/versions

# the output encoding used when revision files
# are written from script.py.mako
output_encoding = utf-8

[alembic:exclude]
tables = spatial_ref_sys


# Logging configuration
[loggers]
keys = root,sqlalchemy,alembic

[handlers]
 keys = console

[formatters]
keys = generic

[logger_root]
level = WARN
handlers = console
qualname =

[logger_sqlalchemy]
level = WARN
handlers =
qualname = sqlalchemy.engine

[logger_alembic]
level = INFO
handlers =
qualname = alembic

[handler_console]
class = StreamHandler
args = (sys.stderr,)
level = NOTSET
formatter = generic

[formatter_generic]
format = %(levelname)-5.5s [%(name)s] %(message)s
datefmt = %H:%M:%S

env.py

    from __future__ import with_statement
import os
import sys
from alembic import context
from sqlalchemy import engine_from_config, pool
from logging.config import fileConfig

parent_dir = os.path.abspath(os.path.join(os.getcwd(), "./app"))
sys.path.append(parent_dir)
from frameworks.database import Base, engine, MetaData
print Base.metadata.tables

# 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)

# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
target_metadata = Base.metadata

# 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.


exclude_tables = config.get_section('alembic:exclude').get('tables', '').split(',')


def include_object(object, name, type_, reflected, compare_to):
    if type_ == "table" and name in exclude_tables:
        return False
    else:
        return True


def get_url():
    return os.getenv('DATABASE_URL', "postgres://localhost/public")


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 = os.getenv('DATABASE_URL', "postgres://localhost/public")
    context.configure(
        url=url, target_metadata=target_metadata, literal_binds=True,
        include_object=include_object)

    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online():
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    """
    print target_metadata.tables
    connectable = engine

    with connectable.connect() as connection:
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            include_object=include_object
        )

        with context.begin_transaction():
            context.run_migrations()

if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()

alembic版本文件

"""add column

Revision ID: 04806a82f806
Revises: 8d27a8fcd1ec
Create Date: 2018-01-29 18:25:19.911399+00:00

"""
from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision = '04806a82f806'
down_revision = '8d27a8fcd1ec'
branch_labels = None
depends_on = None


def upgrade():
    # ### commands auto generated by Alembic - please adjust! ###
    pass
    # ### end Alembic commands ###


def downgrade():
    # ### commands auto generated by Alembic - please adjust! ###
    pass
    # ### end Alembic commands ###

Answer 1

我能够通过设置include_schemas=True（检查数据库端的所有模式）并在env.py中导入模型来解决这个问题（允许alembic检查sqlalchemy端的更新）。 / p>