Ecto: run sql script before or after each migration - dynamic

Question

I would like to create(if not exists) partition tables for each month for some time in the future:
execute """
CREATE TABLE IF NOT EXISTS #{table}_p#{start_date.year}_#{month}
PARTITION OF #{table} FOR VALUES
FROM ('#{start_date}')
TO ('#{stop_date}')
"""
I run it dynamically, eg: for next 12 month starting from today.
I would like to make it during migration, but run it each time migration starts. I can't use Repo since in time of the migration it's not yet started. I didn't find any ability to do it with Ecto.Migration api.
Do you have any ideas how to achieve this?

Answer 1

I made it with support of feature added in ecto 3.5.0. I added separate migration folder wich is used for so called 'repeated_migrations'.
#doc """
repeated migrations are run each deploy(e.g: ensure partitions). Repetition achieved by down method that does nothing.
"""
def run_repeated_migrations do
for repo <- repos() do
path = Ecto.Migrator.migrations_path(repo, "repeated_migrations")
{:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, path, :up, all: true))
{:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, path, :down, all: true))
end
end
method in repeated_migrations/20210427134701_partition_creation.exs
def down do
# to make this migration repeatable we run 'up' following by 'down'. Down do nothing.
execute "SELECT 1"
end