/commanded-spear-adapter

Spear event store adapter for Commanded

Primary LanguageElixirMIT LicenseMIT

CI Hex.pm Hex Docs

Spear EventStoreDB adapter for Commanded

Commanded EvenstoreDB adapter based on spear. The code is based on commanded-extreme-adapter.

Hex package

Changelog

Getting started

The package can be installed from hex as follows.

  1. Add commanded_spear_adapter to your list of dependencies in mix.exs:

    def deps do
  [{:commanded_spear_adapter, "~> 0.2"}]
end

  2. Define and configure your Commanded application:

    defmodule MyApp.Application do
  use Commanded.Application, otp_app: :my_app
end

  3. Configure the Commanded application to use the Commanded.EventStore.Adapters.Spear adapter and set the connection settings for the Event Store you are using:

    # config/config.exs
config :my_app, MyApp.Application,
  event_store: [
    adapter: Commanded.EventStore.Adapters.Spear,
    serializer: Commanded.Serialization.JsonSerializer,
    stream_prefix: "myapp",
    spear: [
      connection_string: "esdb://localhost:2113"
    ]
  ]

    Refer to the Spear library documentation for details on the available connection settings.

    Note: Stream prefix must not contain a dash character ("-").

Partition

This adapter does not support partitioning via the partition_by option.

Multi-node setup

commanded_spear_adapter uses Erlang's :global registry to prevent duplicate subscriptions by stream/name.

Use a serializer other than JSON

To serialize and deserialize events in formats other than JSON, you must specify the content-type of the event body.

# config/config.exs
config :my_app, MyApp.Application,
  event_store: [
    adapter: Commanded.EventStore.Adapters.Spear,
    serializer: MyApp.MessagePackSerializer,
    content_type: "application/x-msgpack"
    ...
  ]

The content_type settings defaults to application/json.

Running the Event Store

You must run the Event Store with all projections enabled and standard projections started.

Use the --run-projections=all --start-standard-projections=true flags when running the Event Store executable.

Credits