Ecto Squash

This is a Mix task intended to streamline migration squashing. It replaces several migrations with a SQL-based migration, which applies schema, and a second one for making sure that all of the squashed migrations has been applied and nothing else, before migrating further. Note: only PostgreSQL is supported yet.

Installation

The package can be installed by adding ecto_squash to your list of dependencies in mix.exs:

def deps do
  [
    {:ecto_squash, "~> x.x.x", only: [:dev]}
  ]
end

Examples

Squash migrations upto and including 20210601033528 into a single one:

  mix ecto.squash --to 20210601033528
  mix ecto.squash --to 20210601033528 -r Custom.Repo

The repository must be set under :ecto_repos in the current app configuration or given via the -r option.

SQL migration will have a filename prefixed with timestamp of the latest migration squashed. That way it won't be applied if squashed migration is already there. Another generated migration will have a +1 second timestamp.

By default, the migration will be generated to the "priv/YOUR_REPO/migrations" directory of the current application but it can be configured to be any subdirectory of priv by specifying the :priv key under the repository configuration.

Command line options

• --to VERSION - squash migrations upto and including VERSION
• -y, --yes - migrate to specified version, remove squashed migrations and migrate to latest version without asking to confirm actions
• -r REPO, --repo REPO - the REPO to generate migration for
• --migrations-path PATH - the PATH to run the migrations from, defaults to priv/repo/migrations
• --no-compile - does not compile applications before running
• --no-deps-check - does not check dependencies before running

Configuration

If :ecto_sql app configuration specifies a custom migration module, the generated migration code will use that rather than the default Ecto.Migration:

  config :ecto_sql, migration_module: MyApplication.CustomMigrationModule