Book seed issue: Tunez.Music.Artist.read had no matching bulk strategy that could be used

When I try to run the first seed script for artists from the book code I get the following error message:

** (Ash.Error.Invalid)
Invalid Error

* Tunez.Music.Artist.read had no matching bulk strategy that could be used.

Requested strategies: [:stream]

Could not use `:stream`: could not stream the query
Could not use `:atomic_batches`: Not in requested strategies
Could not use `:atomic`: Not in requested strategies



Non stream reason:

Action Tunez.Music.Artist.read does not support streaming with one of [:keyset].

There are two ways to handle this.

1.) Use the `allow_stream_with` or `stream_with` options to control what strategies are allowed.
2.) Enable the respective required pagination type on the action read, for example:

    # allow keyset
    pagination keyset?: true, required?: false

    # allow offset
    pagination offset?: true, required?: false

    # allow both
    pagination offset?: true, keyset?: true, required?: false

** (Ash.Error.Invalid)
Invalid Error

* Tunez.Music.Artist.read had no matching bulk strategy that could be used.

Requested strategies: [:stream]

Could not use `:stream`: could not stream the query
Could not use `:atomic_batches`: Not in requested strategies
Could not use `:atomic`: Not in requested strategies



Non stream reason:

Action Tunez.Music.Artist.read does not support streaming with one of [:keyset].

There are two ways to handle this.

1.) Use the `allow_stream_with` or `stream_with` options to control what strategies are allowed.
2.) Enable the respective required pagination type on the action read, for example:

    # allow keyset
    pagination keyset?: true, required?: false

    # allow offset
    pagination offset?: true, required?: false

    # allow both
    pagination offset?: true, keyset?: true, required?: false

This is my Artist resource. I've tried to follow the book, but might have messed something up.

defmodule Tunez.Music.Artist do
  use Ash.Resource, otp_app: :tunez, domain: Tunez.Music, data_layer: AshPostgres.DataLayer

  postgres do
    table "artists"
    repo Tunez.Repo
  end

  actions do
    create :create do
      accept [:name, :biography]
    end

    read :read do
      primary? true
    end

    update :update do
      accept [:name, :biography]
    end

    destroy :destroy do
    end
  end

  attributes do
    uuid_primary_key :id

    attribute :name, :string do
      allow_nil? false
    end

    attribute :biography, :string

    create_timestamp :inserted_at
    update_timestamp :updated_at
  end

  relationships do
    has_many :albums, Tunez.Music.Album
  end
end

defmodule Tunez.Music.Artist do
  use Ash.Resource, otp_app: :tunez, domain: Tunez.Music, data_layer: AshPostgres.DataLayer

  postgres do
    table "artists"
    repo Tunez.Repo
  end

  actions do
    create :create do
      accept [:name, :biography]
    end

    read :read do
      primary? true
    end

    update :update do
      accept [:name, :biography]
    end

    destroy :destroy do
    end
  end

  attributes do
    uuid_primary_key :id

    attribute :name, :string do
      allow_nil? false
    end

    attribute :biography, :string

    create_timestamp :inserted_at
    update_timestamp :updated_at
  end

  relationships do
    has_many :albums, Tunez.Music.Album
  end
end

I am using the unmodified seed script from the code repo: https://github.com/sevenseacat/tunez/blob/main/priv/repo/seeds/01-artists.exs If I remove strategy: :stream from Ash.bulk_destroy! it works.

GitHub

tunez/priv/repo/seeds/01-artists.exs at main · sevenseacat/tunez

The starter application for the Ash Framework book - sevenseacat/tunez

4 Replies

EAJOP•3w ago

As a side note, when cloning the repository and checking out the end-of-chapter-2 branch the seed script works fine, so it looks like I might have done somthing wrong probably

barnabasj•3w ago

Are you on the same Ash version that's also used in the tunez repo? Looked at the code, I think it happens because you created your own read action. It seems that the default read action sets up some pagination defaults as well.

      if type == :read do
        Ash.Resource.Builder.prepend_action(dsl_state, type, type,
          primary?: primary?,
          transaction?: false,
          pagination:
            Ash.Resource.Builder.build_pagination(
              required?: false,
              offset?: true,
              keyset?: true,
              countable: Ash.DataLayer.data_layer_can?(dsl_state, {:query_aggregate, :count})
            )
        )

      if type == :read do
        Ash.Resource.Builder.prepend_action(dsl_state, type, type,
          primary?: primary?,
          transaction?: false,
          pagination:
            Ash.Resource.Builder.build_pagination(
              required?: false,
              offset?: true,
              keyset?: true,
              countable: Ash.DataLayer.data_layer_can?(dsl_state, {:query_aggregate, :count})
            )
        )

so what you would need to do to make your version work is set those options in your read action.

read :read do
  primary? true

  pagination do
    required false
    offset? true
    keyset? true
   end
end

read :read do
  primary? true

  pagination do
    required false
    offset? true
    keyset? true
   end
end

EAJOP•3w ago

I think you're right! Changing it to the default :read solved the problem. Thanks! 🫶

Rebecca Le•2w ago

oooh I didn't know that default read actions did this, good to know

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Book seed issue: Tunez.Music.Artist.read had no matching bulk strategy that could be used

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