View Source AshPostgres.Repo behaviour (ash_postgres v2.0.5)

Resources that use AshPostgres.DataLayer use a Repo to access the database.

This repo is a thin wrapper around an Ecto.Repo.

You can use Ecto.Repo's init/2 to configure your repo like normal, but instead of returning {:ok, config}, use super(config) to pass the configuration to the AshPostgres.Repo implementation.

Installed Extensions

To configure your list of installed extensions, define installed_extensions/0

Extensions can be a string, representing a standard postgres extension, or a module that implements AshPostgres.CustomExtension. That custom extension will be called to generate migrations that serve a specific purpose.

Extensions that are relevant to ash_postgres:

def installed_extensions() do
  ["pg_trgm", "uuid-ossp", "vector", YourCustomExtension]
end

Transaction Hooks

You can define on_transaction_begin/1, which will be invoked whenever a transaction is started for Ash.

This will be invoked with a map containing a type key and metadata.

%{type: :create, %{resource: YourApp.YourResource, action: :action}}

Summary

Callbacks

Return a list of all schema names (only relevant for a multitenant implementation)

Should the repo should be created by mix ash_postgres.create?

The default prefix(postgres schema) to use when building queries

Should the repo should be dropped by mix ash_postgres.drop?

Use this to inform the data layer about what extensions are installed

The path where your migrations are stored

Configure the version of postgres that is being used.

Use this to inform the data layer about the oldest potential postgres version it will be run on.

Allows overriding a given migration type for all fields, for example if you wanted to always use :timestamptz for :utc_datetime fields

The path where your tenant migrations are stored (only relevant for a multitenant implementation)

Callbacks

@callback all_tenants() :: [String.t()]

Return a list of all schema names (only relevant for a multitenant implementation)

@callback create?() :: boolean()

Should the repo should be created by mix ash_postgres.create?

@callback default_prefix() :: String.t()

The default prefix(postgres schema) to use when building queries

@callback drop?() :: boolean()

Should the repo should be dropped by mix ash_postgres.drop?

@callback installed_extensions() :: [String.t() | module()]

Use this to inform the data layer about what extensions are installed

@callback migrations_path() :: String.t() | nil

The path where your migrations are stored

@callback min_pg_version() :: Version.t()

Configure the version of postgres that is being used.

Link to this callback

on_transaction_begin(reason)

View Source
@callback on_transaction_begin(reason :: Ash.DataLayer.transaction_reason()) :: term()

Use this to inform the data layer about the oldest potential postgres version it will be run on.

Must be an integer greater than or equal to 13.

Combining with other tools

For things like Fly.Repo, where you might need to have more fine grained control over the repo module, you can use the define_ecto_repo?: false option to use AshPostgres.Repo.

Link to this callback

override_migration_type(atom)

View Source
@callback override_migration_type(atom()) :: atom()

Allows overriding a given migration type for all fields, for example if you wanted to always use :timestamptz for :utc_datetime fields

Link to this callback

tenant_migrations_path()

View Source
@callback tenant_migrations_path() :: String.t() | nil

The path where your tenant migrations are stored (only relevant for a multitenant implementation)