Ash Elixir•3y ago

How to replace Ecto.Schema modifications?

So I have my custom ULID implementation. It takes UUID format as well as BASE64 url encoded and transforms it to UUID in database layer. When taking out of DB it's transformed to BASE64 again. It creates shorter URLs which is nice. With ecto I needed just 2 lines of code to have all database IDs in this format. But I don't know what's the best way to do it in ash. Also I've modified timestamps to be utc_datetime_usec instead of naive datetime ones. It's easier to convert them to different timezones that way. Here's the code:

defmodule App.Schema do
  defmacro __using__(_env) do
    quote do
      use Ecto.Schema

      @timestamps_opts [
        type: :utc_datetime_usec
      ]
      @primary_key {:id, App.Schema.ULID, autogenerate: true}
      @foreign_key_type App.Schema.ULID

      import Ecto.Changeset
      import Ecto.Query
    end
  end
end

defmodule App.Schema do
  defmacro __using__(_env) do
    quote do
      use Ecto.Schema

      @timestamps_opts [
        type: :utc_datetime_usec
      ]
      @primary_key {:id, App.Schema.ULID, autogenerate: true}
      @foreign_key_type App.Schema.ULID

      import Ecto.Changeset
      import Ecto.Query
    end
  end
end

All I needed to do then was to use App.Schema and it was done. Is there a similar way to do it in Ash? Or at least a way to add ULID in this convenient as a separate data type? In case anyone is interested into my ULID implementation here's gist https://gist.github.com/lamp-town-guy/306694cdb510bd93894c51bb1aaf917e

Gist

ULID Elixir

ULID Elixir. GitHub Gist: instantly share code, notes, and snippets.

9 Replies

ZachDaniel•3y ago

You can do

defmodule App.Resource do
  defmacro __using__(opts) do
    quote do
       use Ash.Resource, unquote(opts)
       
       attributes do
         attribute :id, App.Schema.ULID, generated?: true, default: &App.Schema.ULID.generate/1
         timestamps type: :utc_datetime_usec)
       end
    end
  end
end

defmodule App.Resource do
  defmacro __using__(opts) do
    quote do
       use Ash.Resource, unquote(opts)
       
       attributes do
         attribute :id, App.Schema.ULID, generated?: true, default: &App.Schema.ULID.generate/1
         timestamps type: :utc_datetime_usec)
       end
    end
  end
end

for most of it For the default foreign key type, that is actually a global config currenlty

config :ash, :default_belongs_to_type, App.Schema.ULID

config :ash, :default_belongs_to_type, App.Schema.ULID

You'll need to write an Ash.Type for ULID, although other users here can likely help with that @kernel

kernel•3y ago

👋🏿

defmodule App.Type.ULID do
  use Ash.Type

  @impl Ash.Type
  def storage_type, do: Ecto.ULID.type()

  @impl Ash.Type
  def cast_input(value, _) when is_binary(value) do
    Ecto.Type.cast(Ecto.ULID, String.trim(value))
  end

  def cast_input(value, _) do
    Ecto.Type.cast(Ecto.ULID, value)
  end

  @impl Ash.Type
  def cast_stored(value, constraints) do
    case Ecto.Type.load(Ecto.ULID, value) do
      :error ->
        cast_input(value, constraints)

      {:ok, value} ->
        {:ok, value}
    end
  rescue
    _e in ArgumentError ->
      cast_input(value, constraints)
  end

  @impl Ash.Type
  def dump_to_embedded(value, constraints) do
    cast_input(value, constraints)
  end

  @impl Ash.Type
  def dump_to_native(value, _) do
    Ecto.Type.dump(Ecto.ULID, value)
  end

  def generate(timestamp \\ System.system_time(:millisecond)) do
    timestamp
    |> Ecto.ULID.bingenerate()
    |> Ecto.UUID.load!()
  end
end

defmodule App.Type.ULID do
  use Ash.Type

  @impl Ash.Type
  def storage_type, do: Ecto.ULID.type()

  @impl Ash.Type
  def cast_input(value, _) when is_binary(value) do
    Ecto.Type.cast(Ecto.ULID, String.trim(value))
  end

  def cast_input(value, _) do
    Ecto.Type.cast(Ecto.ULID, value)
  end

  @impl Ash.Type
  def cast_stored(value, constraints) do
    case Ecto.Type.load(Ecto.ULID, value) do
      :error ->
        cast_input(value, constraints)

      {:ok, value} ->
        {:ok, value}
    end
  rescue
    _e in ArgumentError ->
      cast_input(value, constraints)
  end

  @impl Ash.Type
  def dump_to_embedded(value, constraints) do
    cast_input(value, constraints)
  end

  @impl Ash.Type
  def dump_to_native(value, _) do
    Ecto.Type.dump(Ecto.ULID, value)
  end

  def generate(timestamp \\ System.system_time(:millisecond)) do
    timestamp
    |> Ecto.ULID.bingenerate()
    |> Ecto.UUID.load!()
  end
end

i.e:

lamp-town-guyOP•3y ago

Thanks @kernel but in the end I've copied UUID and changed required parts. @Zach Daniel your snippet was useful but there were few things missing. Primary key and allow nil. I have ecto and ash types defined in different files which I might merge together.

attribute :id, App.Type.AshULID,
  generated?: true,
  default: &App.Type.EctoULID.generate/0,
  primary_key?: true,
  allow_nil?: false

attribute :id, App.Type.AshULID,
  generated?: true,
  default: &App.Type.EctoULID.generate/0,
  primary_key?: true,
  allow_nil?: false

But now when I try to create new post in Phoenix example I get this error:

[debug] HANDLE EVENT "create_post" in AppWeb.ExampleLiveView
  Parameters: %{"" => "", "form" => %{"title" => "test"}}
[debug] QUERY OK source="posts" db=0.1ms idle=1995.5ms
SELECT p0."id", p0."inserted_at", p0."updated_at", p0."title", p0."content" FROM "posts" AS p0 []
↳ AshPostgres.DataLayer.run_query/2, at: lib/data_layer.ex:613

[debug] HANDLE EVENT "create_post" in AppWeb.ExampleLiveView
  Parameters: %{"" => "", "form" => %{"title" => "test"}}
[debug] QUERY OK source="posts" db=0.1ms idle=1995.5ms
SELECT p0."id", p0."inserted_at", p0."updated_at", p0."title", p0."content" FROM "posts" AS p0 []
↳ AshPostgres.DataLayer.run_query/2, at: lib/data_layer.ex:613

How do I get to more verbose error message?

ZachDaniel•3y ago

I don’t see an error there. Is that all the logs you have?

lamp-town-guyOP•3y ago

Well, that's all I get when I want to create a blog post. I have nothing in the database so it should be created.

ZachDaniel•3y ago

🤔 are you rendering errors in your form in any way? In your error branch of submitting the form, try inspecting the result of this: AshPhoenix.Form.errors(form, for_path: :all) Might shed some light on what is going on

lamp-town-guyOP•3y ago

Well, I might contribute to phoenix guide because there are no error messages in the blog example. I expected it to be there. Default value is not being generated correctly.

   errors: [
     %Ash.Error.Changes.InvalidAttribute{
       field: :id,
       message: "is invalid",
       private_vars: nil,
       value: &App.Type.EctoULID.generate/1,
       changeset: nil,
       query: nil,
       error_context: [],
       vars: [field: :id, message: "is invalid"],
       path: [],
       stacktrace: #Stacktrace<>,
       class: :invalid
     }
   ],

   errors: [
     %Ash.Error.Changes.InvalidAttribute{
       field: :id,
       message: "is invalid",
       private_vars: nil,
       value: &App.Type.EctoULID.generate/1,
       changeset: nil,
       query: nil,
       error_context: [],
       vars: [field: :id, message: "is invalid"],
       path: [],
       stacktrace: #Stacktrace<>,
       class: :invalid
     }
   ],

ZachDaniel•3y ago

Yeah, so since id isn't part of your form, and I assume there is no corresponding error tag What some people will do is something like this:

if @form.source.just_submitted? do # or just @form.just_submitted? pre 1.7
  Please address the errors with your form submission.

  for {path, errors} <- AshPhoenix.Form.errors(form, for_path: :all) do
    for {field, error} <- errors do
      <%= Enum.join(path ++ [field], ".") %>: <%= error %>
    end
  end
end

if @form.source.just_submitted? do # or just @form.just_submitted? pre 1.7
  Please address the errors with your form submission.

  for {path, errors} <- AshPhoenix.Form.errors(form, for_path: :all) do
    for {field, error} <- errors do
      <%= Enum.join(path ++ [field], ".") %>: <%= error %>
    end
  end
end

lamp-town-guyOP•3y ago

OK I feel super dumb. default: &App.Type.EctoULID.generate/1 was supposed to be default: &App.Type.EctoULID.generate/0. Thanks, it's working now.

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How to replace Ecto.Schema modifications?

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