如何解决 heroku 上的应用程序错误？

Question

I am trying to create an app on django and I am trying to host it on heroku. Everything runs perfectly locally. I get an error while trying to migrate the database onto the heroku app by running command -

heroku run python manage.py migrate

This is the error I am getting -

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"

settings.py -

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

settings.py ( database section ) -

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'"
        }
    }
}
        

How can I solve this issue? Please ask if I need to add any of my files onto the question.

Answer 1

You are using MySQL for local development and PostgreSQL in production. The PostgreSQL connection is coming from the DATABASE_URL environment variable that dj_database_url uses by default.

Since you are updating your default database from the environment (not replacing it), the MySQL-specific init_command option is being left in your PostgreSQL configuration. The psycopg2 PostgreSQL driver doesn't know what to do with it.

A quick and dirty solution would be to completely your default database configuration instead of updating it:

DATABASES['default'] = prod_db

But I strongly urge you to use the same database server for development and production. As you have discovered, database engines aren't drop-in replacements for each other. In this case, it's likely easiest to switch from PostgreSQL to MySQL on Heroku.

First, let's get rid of the Postgres stuff:

• Remove psycopg2 from your dependencies. Its presence likely caused Heroku to automatically provision a PostgreSQL database for you , which added to the confusion.
• Optionally, de-provision the existing Postgres database. It's probably the free version so it isn't costing you anything, but it's a bit weird to have it hanging around if you are using a completely different database server.

Now, provision a MySQL server. I suggest you pick from the available addons . There are a few MySQL options, including JawsDB and ClearDB. Here is an example using ClearDB :

heroku addons:create cleardb:ignite

Ignite is the free tier for ClearDB. Once provisioned, your app will see a new environment variable CLEARDB_DATABASE_URL . Other addons will use other environment variable names, so make sure to read their documentation.

Finally, update your Django configuration. dj_database_url uses the DATABASE_URL environment variable by default, but we can tell it to use another :

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