PerhapDynamo

Perhap Dynamo is a persistance adapter for Perhap.

Current Status

Perhap dynamo is a work in progress. It can store events and will store models.

Limitations

Try to refrain from using atoms in the data store as either keys or values unless you are prepared to manually convert them. This library is able to automatically convert atoms to strings for storage in dynamo but it can't automatically convert them back.

Installation

Perhap Dynamo can be added to your project by adding perhap_dynamo to your list of dependencies in mix.exs:

def deps do
  [
    #...
    {:perhap, github: "perhap/perhap"},
    {:perhap_dynamo, github: "perhap/perhap_dynamo"}
  ]
end

You should then add perhap and perhap_dynamo to your applications in mix.exs:

# Run "mix help compile.app" to learn about applications.
def application do
  [
    applications: [:perhap, :perhap_dynamo],
    extra_applications: [:logger],
    #...
  ]
end

Config

Perhap Dynamo can then be configured like the following in config/config.exs:

config :perhap,
  port: 9000,
  eventstore: Perhap.Adapters.Eventstore.Dynamo,
  modelstore: Perhap.Adapters.Modelstore.Memory

config :logger,
  backends: [:console],
  compile_time_purge_level: :info,
  level: :warn

config :swarm,
  sync_nodes_timeout: 10

You can also set your aws credentials using the following config options:

config :ex_aws,
  access_key_id: "your-access-key",
  secret_access_key: "your-secret-key"

Don't commit that to your source control. ExAws, the AWS library this one uses will also accept the environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY. So you can also pass in your keys by setting those e.g.

AWS_ACCESS_KEY_ID="your-access-key" AWS_SECRET_ACCESS_KEY="your-secret-key" mix test

See ExAws for more AWS options.

Dynamo Tables

Set up your tables in advance using AWS web ui or ExAws. Perhap Dynamo expects a table for events with a string primary key called event_id and an index table with context as a primary key and entity_id, both strings.

Once created set the following config values:

config :perhap_dynamo,
  event_table_name: "your-event-table-name",
  event_index_table_name: "your-index-table-name"