Define ignored tables in alembic.ini

Exclude_tables.md

Add this in your ini file:

[alembic:exclude]
tables = spatial_ref_sys

In env.py:

    import re 
    
    def exclude_tables_from_config(config_):
        tables_ = config_.get("tables", None)
        if tables_ is not None:
            tables = tables_.split(",")
        return tables
        
    # Changes from: https://gist.github.com/utek/6163250#gistcomment-3851168
    exclude_tables = re.sub(r"\s+", '',  # replace whitespace
                        config.get_main_option('exclude', '')).split(',')


    def include_object(object, name, type_, *args, **kwargs):
        return not (type_ == 'table' and name in exclude_tables)
     
    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 = config.get_main_option("sqlalchemy.url")
        context.configure(url=engine.url, 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.
    
        """
        if isinstance(engine, Engine):
            connection = engine.connect()
        else:
            raise Exception('Expected engine instance got %s instead' % type(engine))
    
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            include_object=include_object
        )
    
        try:
            with context.begin_transaction():
                context.run_migrations()
        finally:
            connection.close()

Looks like this is the solution I was looking for. But I got this error: NameError: global name 'engine' is not defined.

Probably some version discrepancy. This one works for me:
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 = config.get_main_option("sqlalchemy.url")
context.configure(url=url, 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.

"""
engine = engine_from_config(
            config.get_section(config.config_ini_section),
            prefix='sqlalchemy.',
            poolclass=pool.NullPool)

connection = engine.connect()
context.configure(
            connection=connection,
            target_metadata=target_metadata,
            include_object = include_object
            )

try:
    with context.begin_transaction():
        context.run_migrations()
finally:
    connection.close()

Hi,

Thanks for this. Big help.

Thanks tor this 👍

👍

You can get rid of the first function altogether by just doing

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

This is great!
Thank you.

Awesome 💯 thanks

Super useful, thanks!

Very helpful!

Very Helpful Kudos !! 👍 👍

After 6 years this gist is still being used :) Thank you :)

If you want to use it in the main config section, and want to support YAML lists:

[alembic]
exclude_tables =
    quux
    eggs, foo,
    ham, bar
    baz

def get_list_from_config(config, key):
    arr = config.get_main_option(key, [])
    if arr:
        # split on newlines and commas, then trim (I mean strip)
        arr = [token for a in arr.split('\n') for b in a.split(',') if (token := b.strip())]
    return arr


exclude_tables = get_list_from_config(config, "exclude_tables")

To get

['quux', 'eggs', 'foo', 'ham', 'bar', 'baz']

If you want to use it in the main config section, and want to support YAML lists:

[alembic]
exclude_tables =
    quux
    eggs, foo,
    ham, bar
    baz

def get_list_from_config(config, key):
    arr = config.get_main_option(key, None)
    if arr is not None:
        # split on newlines and commas, then trim (I mean strip)
        arr = [token for a in arr.split('\n') for b in a.split(',') if (token := b.strip())]
    return arr


exclude_tables = get_list_from_config(config, "exclude_tables")

To get

['quux', 'eggs', 'foo', 'ham', 'bar', 'baz']

+1

I've found that both alembic.ini and the first few functions and calls in the gist can be greatly simplified:

In alembic ini simply add a value in the main config section (by sqlalchemy.url, for example):

# Exclude the following tables from being detected for migrations
exclude = spatial_ref_sys

And in env.py all you need is:

exclude_tables = config.get_main_option('exclude', '').split(',')


def include_object(object, name, type_, *args, **kwargs):
    if type_ == 'table' and name in exclude_tables:
        return False
    else:
        return True

Then just edit run_migrations_offline and run_migrations_online to use the newly defined include_object function just like the original gist.

Still working perfectly, thanks!

works perfectly, for a single exclude!

just a little optimization so this also works:

exclude = spatial_ref_sys, us_lex, us_rules, us_gaz

env.py

exclude_tables = re.sub(r"\s+", '',  # replace whitespace
                        config.get_main_option('exclude', '')).split(',')


def include_object(object, name, type_, *args, **kwargs):
    return not (type_ == 'table' and name in exclude_tables)

Elegant! Thanks @mskoric

@mskoric Thank you. I've update the gist with your changes.

I had to make this change for exclude_tables to work:

exclude_tables = re.sub(
    r"\s+",
    "",
    config.get_section_option("alembic:exclude", "tables"),  # replace whitespace
).split(",")

Other than that, worked great. Thanks!

@xoelop Thank you, I needed alembic:exclude" and not just "exclude"

Another approach is given in the docs if instead of explicitly excluding tables, you would for example prefer to include tables only defined in the model (which turned out to my reason ending up here 😀):

target_metadata = MyModel.metadata

def include_name(name, type_, parent_names):
    if type_ == "table":
        return name in target_metadata.tables
    else:
        return True

and then passed to context in the run functions as before:

context.configure(
    # ...
    target_metadata = target_metadata,
    include_name = include_name,
    include_schemas = False
)

@heathhenley Simple! and working perfectly for me. Thanks👍

@heathhenley Works like a charm, thanks!

thanks, everything worked 👍👍

In addition to @heathhenley comment, you need to configure context in do_run_migrations, which will be executed in run_migrations online.

def do_run_migrations(connection: Connection) -> None:
    context.configure(
        connection=connection,
        target_metadata=target_metadata,
        include_name=include_name,
        include_schemas=False
    )

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