How to use two databases: Postgres and Snowflake with alembic and sqlachemy? - python-3.x

Question

I want to use two databases: Postgres and Snowflake using alembic migration tool in a single fastapi app.
Able to perform alembic migrations and alembic upgrade if using single database i.e. Postgres but on using multiple databases alembic is creating problems.
Tried using snowflake database independently on a different app with only snowflake as a database. It is working perfectly fine with revisions and alembic upgrade but not working on a single app with two databases.
Here is my directory structure as suggested in few articles:
main-project-->
postgres-migration-->
versions/
env.py
README
script.py.mako
snowflake-migration-->
versions/
env.py
README
script.py.mako
Here is my alembic.ini file generated for postgres, but I manipulated it to support snowflake:
# A generic, single database configuration.
[alembic]
# path to migration scripts
script_location = db-migration
[A_SNOWFLAKE_SCHEMA]
# path to env.py and migration scripts for schema1
script_location = snowflake-db-migration
# template used to generate migration files
# file_template = %%(rev)s_%%(slug)s
# sys.path path, will be prepended to sys.path if present.
# defaults to the current working directory.
prepend_sys_path = .
# 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 =
# 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 db-migration/versions. When using multiple version
# directories, initial revisions must be specified with --version-path
# version_locations = %(here)s/bar %(here)s/bat db-migration/versions
# the output encoding used when revision files
# are written from script.py.mako
# output_encoding = utf-8
#sqlalchemy.url = driver://user:pass#localhost/dbname
[post_write_hooks]
# post_write_hooks defines scripts or Python functions that are run
# on newly generated revision scripts. See the documentation for further
# detail and examples
# format using "black" - use the console_scripts runner, against the "black" entrypoint
# hooks = black
# black.type = console_scripts
# black.entrypoint = black
# black.options = -l 79 REVISION_SCRIPT_FILENAME
# 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
Above file is able to create revision scripts inside versions/ folder of snowflake-db-migration. But not able to run the generated revision using(throwing errors):
alembic upgrade head
How to convert this .ini file to support multi-database .ini file?
Tried using command:
alembic init --template multidb snowflake-db-migration
But not sure how to integrate changes here.
Also don't want to hardcode sqlalchemy.url variable in .ini file as required to use snowflake variables from a .toml file which contains all environment variables.
There are few answers but none of them are accepted and exactly similar to my use case.