eventstore v0.1.0 EventStore

EventStore client API to read and write events to a logical event stream

Each of the following client functions expects to receive an already started & initialised EventStore.Storage pid.

Example usage

# start the EventStore process
{:ok, store} = EventStore.start_link

# append events to stream
{:ok, events} = EventStore.append_to_stream(store, stream_uuid, expected_version, events)

# read all events from the stream, starting at the beginning
{:ok, recorded_events} = EventStore.read_stream_forward(store, stream_uuid)

Summary

Functions

append_to_stream(store, stream_uuid, expected_version, events)

Append one or more events to a stream atomically

read_stream_forward(store, stream_uuid, start_version \\ 0, count \\ nil)

Reads the requested number of events from the given stream, in the order in which they were originally written

start_link()

Start the EventStore process (including storage and subscriptions) and connect to PostgreSQL

subscribe_to_all_streams(store, subscription_name, subscriber)

Subscriber will be notified of each event persisted to any stream, once the subscription is established

subscribe_to_stream(store, stream_uuid, subscription_name, subscriber)

Subscriber will be notified of each event persisted to a single stream, once the subscription is established

Functions

append_to_stream(store, stream_uuid, expected_version, events)

Append one or more events to a stream atomically.

storage an already started EventStore pid.
stream_uuid is used to uniquely identify a stream.
expected_version is used for optimistic concurrency. Specify 0 for the creation of a new stream. An {:error, wrong_expected_version} response will be returned if the stream already exists. Any positive number will be used to ensure you can only append to the stream if it is at exactly that version.
events is a list of %EventStore.EventData{} structs

read_stream_forward(store, stream_uuid, start_version \\ 0, count \\ nil)

Reads the requested number of events from the given stream, in the order in which they were originally written.

storage an already started EventStore pid.
stream_uuid is used to uniquely identify a stream.
start_version optionally, the version number of the first event to read. Defaults to the beginning of the stream if not set.
count optionally, the maximum number of events to read. If not set it will return all events from the stream.

start_link()

Start the EventStore process (including storage and subscriptions) and connect to PostgreSQL.

subscribe_to_all_streams(store, subscription_name, subscriber)

Subscriber will be notified of each event persisted to any stream, once the subscription is established.

store an already started EventStore pid.
subscription_name is used to name the subscription group.
subscriber is a process that will receive {:event, event} callback messages.

Returns {:ok, subscription} when subscription succeeds.

subscribe_to_stream(store, stream_uuid, subscription_name, subscriber)

Subscriber will be notified of each event persisted to a single stream, once the subscription is established.

store an already started EventStore pid.
stream_uuid is the stream to subscribe to. Use the $all identifier to subscribe to events from all streams.
subscription_name is used to name the subscription group.
subscriber is a process that will receive {:event, event} callback messages.

Returns {:ok, subscription} when subscription succeeds.