如何解决 heroku 上的应用程序错误？

Question

我正在尝试在 django 上创建一个应用程序，并试图在 heroku 上托管它。一切都在本地完美运行。 尝试通过运行命令将数据库迁移到 heroku 应用程序时出现错误 -

heroku run python manage.py migrate

这是我得到的错误 -

Traceback (most recent call last):
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/base/base.py", line 230, in ensure_connection
    self.connect()
  File "/app/.heroku/python/lib/python3.9/site-packages/django/utils/asyncio.py", line 25, in inner
    return func(*args, **kwargs)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/base/base.py", line 211, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/utils/asyncio.py", line 25, in inner
    return func(*args, **kwargs)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/postgresql/base.py", line 199, in get_new_connection
    connection = Database.connect(**conn_params)
  File "/app/.heroku/python/lib/python3.9/site-packages/psycopg2/__init__.py", line 121, in connect
    dsn = _ext.make_dsn(dsn, **kwargs)
  File "/app/.heroku/python/lib/python3.9/site-packages/psycopg2/extensions.py", line 167, in make_dsn
    parse_dsn(dsn)
psycopg2.ProgrammingError: invalid dsn: invalid connection option "init_command"


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/app/manage.py", line 22, in <module>
    main()
  File "/app/manage.py", line 18, in main
    execute_from_command_line(sys.argv)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/core/management/__init__.py", line 425, in execute_from_command_line
    utility.execute()
  File "/app/.heroku/python/lib/python3.9/site-packages/django/core/management/__init__.py", line 419, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/core/management/base.py", line 373, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/core/management/base.py", line 417, in execute
    output = self.handle(*args, **options)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/core/management/base.py", line 90, in wrapped
    res = handle_func(*args, **kwargs)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/core/management/commands/migrate.py", line 75, in handle
    self.check(databases=[database])
  File "/app/.heroku/python/lib/python3.9/site-packages/django/core/management/base.py", line 438, in check
    all_issues = checks.run_checks(
  File "/app/.heroku/python/lib/python3.9/site-packages/django/core/checks/registry.py", line 77, in run_checks
    new_errors = check(app_configs=app_configs, databases=databases)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/core/checks/model_checks.py", line 34, in check_all_models
    errors.extend(model.check(**kwargs))
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/models/base.py", line 1307, in check
    *cls._check_indexes(databases),
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/models/base.py", line 1699, in _check_indexes
    connection.features.supports_covering_indexes or
  File "/app/.heroku/python/lib/python3.9/site-packages/django/utils/functional.py", line 48, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/postgresql/features.py", line 84, in is_postgresql_11
    return self.connection.pg_version >= 110000
  File "/app/.heroku/python/lib/python3.9/site-packages/django/utils/functional.py", line 48, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/postgresql/base.py", line 339, in pg_version
    with self.temporary_connection():
  File "/app/.heroku/python/lib/python3.9/contextlib.py", line 119, in __enter__
    return next(self.gen)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/base/base.py", line 614, in temporary_connection
    with self.cursor() as cursor:
  File "/app/.heroku/python/lib/python3.9/site-packages/django/utils/asyncio.py", line 25, in inner
    return func(*args, **kwargs)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/base/base.py", line 270, in cursor
    return self._cursor()
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/base/base.py", line 246, in _cursor
    self.ensure_connection()
  File "/app/.heroku/python/lib/python3.9/site-packages/django/utils/asyncio.py", line 25, in inner
    return func(*args, **kwargs)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/base/base.py", line 230, in ensure_connection
    self.connect()
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/utils.py", line 90, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/base/base.py", line 230, in ensure_connection
    self.connect()
  File "/app/.heroku/python/lib/python3.9/site-packages/django/utils/asyncio.py", line 25, in inner
    return func(*args, **kwargs)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/base/base.py", line 211, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/utils/asyncio.py", line 25, in inner
    return func(*args, **kwargs)
  File "/app/.heroku/python/lib/python3.9/site-packages/django/db/backends/postgresql/base.py", line 199, in get_new_connection
    connection = Database.connect(**conn_params)
  File "/app/.heroku/python/lib/python3.9/site-packages/psycopg2/__init__.py", line 121, in connect
    dsn = _ext.make_dsn(dsn, **kwargs)
  File "/app/.heroku/python/lib/python3.9/site-packages/psycopg2/extensions.py", line 167, in make_dsn
    parse_dsn(dsn)
django.db.utils.ProgrammingError: invalid dsn: invalid connection option "init_command"

设置.py -

prod_db  =  dj_database_url.config(conn_max_age=500)
DATABASES['default'].update(prod_db)

settings.py（数据库部分）-

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': '****',
        'USER': '****',
        'PASSWORD': '****',
        'HOST': '127.0.0.1',
        'PORT': '3306',
        'OPTIONS': {
            'init_command': "SET sql_mode='STRICT_TRANS_TABLES'"
        }
    }
}
        

我该如何解决这个问题？ 请询问我是否需要将我的任何文件添加到问题中。

Answer 1

您在本地开发中使用MySQL ，在生产中使用 PostgreSQL。 PostgreSQL 连接来自dj_database_url默认使用的DATABASE_URL环境变量。

由于您是从环境更新默认数据库（而不是替换它），因此 PostgreSQL 配置中保留了 MySQL 特定的init_command选项。 psycopg2 PostgreSQL 驱动程序不知道如何处理它。

一个快速而肮脏的解决方案是完全使用默认数据库配置而不是更新它：

DATABASES['default'] = prod_db

但我强烈建议您使用同一台数据库服务器进行开发和生产。 正如您所发现的，数据库引擎并不是彼此的直接替代品。 在这种情况下，在 Heroku 上从 PostgreSQL 切换到 MySQL 可能是最简单的。

首先，让我们摆脱 Postgres 的东西：

• 从依赖项中删除psycopg2 。 它的存在可能导致 Heroku 自动为您提供一个 PostgreSQL 数据库，这增加了混乱。
• 或者，取消供应现有的 Postgres 数据库。 它可能是免费版本，因此不会花费您任何费用，但如果您使用的是完全不同的数据库服务器，那么让它闲逛有点奇怪。

现在，提供一个 MySQL 服务器。 我建议您从可用的插件中挑选。 有几个 MySQL 选项，包括 JawsDB 和 ClearDB。 这是一个使用 ClearDB 的示例：

heroku addons:create cleardb:ignite

Ignite 是 ClearDB 的免费层。 配置后，您的应用程序将看到一个新的环境变量CLEARDB_DATABASE_URL 。 其他插件将使用其他环境变量名称，因此请务必阅读它们的文档。

最后，更新您的 Django 配置。 dj_database_url默认使用DATABASE_URL环境变量，但我们可以告诉它使用另一个：

prod_db = dj_database_url.config(env="CLEARDB_DATABASE_URL", conn_max_age=500)
DATABASES['default'].update(prod_db)