Is it possible to store the alembic connect string outside of alembic.ini?

I had the very same problem yesterday and found a following solution to work.I do the following in alembic/env.py:

# this is the Alembic Config object, which provides# access to the values within the .ini file in use.config = context.config# this will overwrite the ini-file sqlalchemy.url path# with the path given in the config of the main codeimport config as ems_configconfig.set_main_option('sqlalchemy.url', ems_config.config.get('sql', 'database'))

ems_config is an external module that holds my configuration data.

config.set_main_option(...) essentially overwrites the sqlalchemy.url key in the [alembic] section of the alembic.ini file. In my configuration I simply leave it black.

The simplest thing I could come up with to avoid commiting my user/pass was to a) add in interpolation strings to the alembic.ini file, and b) set these interpolation values in env.py

alembic.ini

sqlalchemy.url = postgresql://%(DB_USER)s:%(DB_PASS)s@35.197.196.146/nozzle-website

env.py

import osfrom logging.config import fileConfigfrom sqlalchemy import engine_from_configfrom sqlalchemy import poolfrom alembic import context# this is the Alembic Config object, which provides# access to the values within the .ini file in use.config = context.config# here we allow ourselves to pass interpolation vars to alembic.ini# fron the host envsection = config.config_ini_sectionconfig.set_section_option(section, "DB_USER", os.environ.get("DB_USER"))config.set_section_option(section, "DB_PASS", os.environ.get("DB_PASS"))...

Alembic documentation suggests using create_engine with the database URL (instead of modifying sqlalchemy.url in code).

Also you should modify run_migrations_offline to use the new URL. Allan Simon has an example on his blog, but in summary, modify env.py to:

1. Provide a shared function to get the URL somehow (here it comes from the command line):

   def get_url():    url = context.get_x_argument(as_dictionary=True).get('url')    assert url, "Database URL must be specified on command line with -x url=<DB_URL>"    return url

2. Use the URL in offline mode:

   def run_migrations_offline():    ...    url = get_url()    context.configure(        url=url, target_metadata=target_metadata, literal_binds=True)    ...

3. Use the URL in online mode by using create_engine instead of engine_from_config:

   def run_migrations_online():    ...    connectable = create_engine(get_url())    with connectable.connect() as connection:    ...