Commanded Ecto Projections

Read model projections for Commanded CQRS/ES applications using Ecto for persistence.

Read the Changelog for recent changes and the Hex Docs on API usage.

This README and the following guides follow the master branch which may not be the currently published version.

Overview

• Getting started
• Usage
  • Creating a read model
  • Creating a projector
  • Supervision
  • Error handling
    • error/3 callback
    • Error handling example
  • after_update/3 callback
  • Schema prefix
  • Rebuilding a projection

Example projector

defmodule MyApp.ExampleProjector do
  use Commanded.Projections.Ecto,
    application: MyApp.Application,
    repo: MyApp.Projections.Repo,
    name: "MyApp.ExampleProjector"

  project %AnEvent{} = event, _metadata, fn multi ->
    %AnEvent{name: name} = event

    projection = %ExampleProjection{name: name}

    Ecto.Multi.insert(multi, :example_projection, projection)
  end
end

Contributing

Pull requests to contribute new or improved features, and extend documentation are most welcome. Please follow the existing coding conventions.

You should include unit tests to cover any changes. Run mix test to execute the test suite:

mix deps.get
MIX_ENV=test mix setup
mix test

Contributors

• Andrey Akulov
• Ben Smith
• CptBreeza
• Florian Ebeling
• Sascha Wolf
• Tobiasz Małecki

Need help?

Please open an issue if you encounter a problem, or need assistance. You can also seek help in the #commanded channel in the official Elixir Slack.

Copyright and License

Copyright (c) 2017 Ben Smith

This library is released under the MIT License. See the LICENSE.md file for further details.