Commanded

v0.19.1

Commanded v0.19.1 Commanded.EventStore behaviour View Source

Defines the behaviour to be implemented by an event store adapter to be used by Commanded.

Link to this section Summary

Types

error()
expected_version()
snapshot()
source_uuid()
start_from()
stream_uuid()
subscriber()
subscription()
subscription_name()

Functions

ack_event(pid, event)

Acknowledge receipt and successful processing of the given event received from a subscription to an event stream.

append_to_stream(stream_uuid, expected_version, events)

Append one or more events to a stream atomically.

child_spec()
delete_snapshot(source_uuid)

Delete a previously recorded snapshot for a given source

delete_subscription(stream_uuid, subscription_name)

Delete an existing subscription.

event_store_adapter()

Get the configured event store adapter

read_snapshot(source_uuid)

Read a snapshot, if available, for a given source.

record_snapshot(snapshot)

Record a snapshot of the data and metadata for a given source

stream_forward(stream_uuid, start_version \\ 0, read_batch_size \\ 1000)

Streams events from the given stream, in the order in which they were originally written.

subscribe(stream_uuid)

Create a transient subscription to a single event stream.

subscribe_to(stream_uuid, subscription_name, subscriber, start_from)

Create a persistent subscription to an event stream.

unsubscribe(subscription)

Unsubscribe an existing subscriber from all event notifications.

Callbacks

ack_event(pid, arg2)

Acknowledge receipt and successful processing of the given event received from a subscription to an event stream.

append_to_stream(stream_uuid, expected_version, events)

Append one or more events to a stream atomically.

child_spec()

Return a child spec defining all processes required by the event store.

delete_snapshot(source_uuid)

Delete a previously recorded snapshot for a given source

delete_subscription(arg1, subscription_name)

Delete an existing subscription.

read_snapshot(source_uuid)

Read a snapshot, if available, for a given source.

record_snapshot(snapshot)

Record a snapshot of the data and metadata for a given source

stream_forward(stream_uuid, start_version, read_batch_size)

Streams events from the given stream, in the order in which they were originally written.

subscribe(arg1)

Create a transient subscription to a single event stream.

subscribe_to(arg1, subscription_name, subscriber, start_from)

Create a persistent subscription to an event stream.

unsubscribe(subscription)

Unsubscribe an existing subscriber from event notifications.

Link to this section Types

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error()

View Source 
error() :: term()
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expected_version()

View Source 
expected_version() ::
  :any_version | :no_stream | :stream_exists | non_neg_integer()
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snapshot()

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snapshot() :: Commanded.EventStore.SnapshotData.t()
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source_uuid()

View Source 
source_uuid() :: String.t()
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start_from()

View Source 
start_from() :: :origin | :current | integer()
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stream_uuid()

View Source 
stream_uuid() :: String.t()
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subscriber()

View Source 
subscriber() :: pid()
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subscription()

View Source 
subscription() :: any()
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subscription_name()

View Source 
subscription_name() :: String.t()

Link to this section Functions

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ack_event(pid, event)

View Source 
ack_event(pid(), Commanded.EventStore.RecordedEvent.t()) :: :ok

Acknowledge receipt and successful processing of the given event received from a subscription to an event stream.

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append_to_stream(stream_uuid, expected_version, events)

View Source 
append_to_stream(
  stream_uuid(),
  expected_version(),
  events :: [Commanded.EventStore.EventData.t()]
) :: :ok | {:error, :wrong_expected_version} | {:error, error()}

Append one or more events to a stream atomically.

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child_spec()

View Source 
child_spec() :: [:supervisor.child_spec()]
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delete_snapshot(source_uuid)

View Source 
delete_snapshot(source_uuid()) :: :ok | {:error, error()}

Delete a previously recorded snapshot for a given source

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delete_subscription(stream_uuid, subscription_name)

View Source 
delete_subscription(stream_uuid() | :all, subscription_name()) ::
  :ok | {:error, :subscription_not_found} | {:error, error()}

Delete an existing subscription.

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event_store_adapter()

View Source

Get the configured event store adapter

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read_snapshot(source_uuid)

View Source 
read_snapshot(source_uuid()) ::
  {:ok, snapshot()} | {:error, :snapshot_not_found}

Read a snapshot, if available, for a given source.

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record_snapshot(snapshot)

View Source 
record_snapshot(snapshot()) :: :ok | {:error, error()}

Record a snapshot of the data and metadata for a given source

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stream_forward(stream_uuid, start_version \\ 0, read_batch_size \\ 1000)

View Source 
stream_forward(
  stream_uuid(),
  start_version :: non_neg_integer(),
  read_batch_size :: non_neg_integer()
) :: Enumerable.t() | {:error, :stream_not_found} | {:error, error()}

Streams events from the given stream, in the order in which they were originally written.

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subscribe(stream_uuid)

View Source 
subscribe(stream_uuid() | :all) :: :ok | {:error, error()}

Create a transient subscription to a single event stream.

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subscribe_to(stream_uuid, subscription_name, subscriber, start_from)

View Source 
subscribe_to(
  stream_uuid() | :all,
  subscription_name(),
  subscriber(),
  start_from()
) ::
  {:ok, subscription()}
  | {:error, :subscription_already_exists}
  | {:error, error()}

Create a persistent subscription to an event stream.

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unsubscribe(subscription)

View Source 
unsubscribe(subscription()) :: :ok

Unsubscribe an existing subscriber from all event notifications.

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ack_event(pid, arg2)

View Source 
ack_event(pid(), Commanded.EventStore.RecordedEvent.t()) :: :ok

Acknowledge receipt and successful processing of the given event received from a subscription to an event stream.

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append_to_stream(stream_uuid, expected_version, events)

View Source 
append_to_stream(
  stream_uuid(),
  expected_version(),
  events :: [Commanded.EventStore.EventData.t()]
) :: :ok | {:error, :wrong_expected_version} | {:error, error()}

Append one or more events to a stream atomically.

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child_spec()

View Source 
child_spec() :: [:supervisor.child_spec()]

Return a child spec defining all processes required by the event store.

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delete_snapshot(source_uuid)

View Source 
delete_snapshot(source_uuid()) :: :ok | {:error, error()}

Delete a previously recorded snapshot for a given source

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delete_subscription(arg1, subscription_name)

View Source 
delete_subscription(stream_uuid() | :all, subscription_name()) ::
  :ok | {:error, :subscription_not_found} | {:error, error()}

Delete an existing subscription.

Example 

:ok = Commanded.EventStore.delete_subscription(:all, "Example")
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read_snapshot(source_uuid)

View Source 
read_snapshot(source_uuid()) ::
  {:ok, snapshot()} | {:error, :snapshot_not_found}

Read a snapshot, if available, for a given source.

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record_snapshot(snapshot)

View Source 
record_snapshot(snapshot()) :: :ok | {:error, error()}

Record a snapshot of the data and metadata for a given source

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stream_forward(stream_uuid, start_version, read_batch_size)

View Source 
stream_forward(
  stream_uuid(),
  start_version :: non_neg_integer(),
  read_batch_size :: non_neg_integer()
) :: Enumerable.t() | {:error, :stream_not_found} | {:error, error()}

Streams events from the given stream, in the order in which they were originally written.

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subscribe(arg1)

View Source 
subscribe(stream_uuid() | :all) :: :ok | {:error, error()}

Create a transient subscription to a single event stream.

The event store will publish any events appended to the given stream to the subscriber process as an {:events, events} message.

The subscriber does not need to acknowledge receipt of the events.

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subscribe_to(arg1, subscription_name, subscriber, start_from)

View Source 
subscribe_to(
  stream_uuid() | :all,
  subscription_name(),
  subscriber(),
  start_from()
) ::
  {:ok, subscription()}
  | {:error, :subscription_already_exists}
  | {:error, error()}

Create a persistent subscription to an event stream.

To subscribe to all events appended to any stream use :all as the stream when subscribing.

The event store will remember the subscribers last acknowledged event. Restarting the named subscription will resume from the next event following the last seen.

Once subscribed, the subscriber process should be sent a {:subscribed, subscription} message to allow it to defer initialisation until the subscription has started.

The subscriber process will be sent all events persisted to any stream. It will receive a {:events, events} message for each batch of events persisted for a single aggregate.

The subscriber must ack each received, and successfully processed event, using Commanded.EventStore.ack_event/2.

Examples

Subscribe to all streams:

{:ok, subscription} =
  Commanded.EventStore.subscribe_to(:all, "Example", self(), :current)

Subscribe to a single stream:

{:ok, subscription} =
  Commanded.EventStore.subscribe_to("stream1", "Example", self(), :origin)
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unsubscribe(subscription)

View Source 
unsubscribe(subscription()) :: :ok

Unsubscribe an existing subscriber from event notifications.

This will not delete the subscription.

Example 

:ok = Commanded.EventStore.unsubscribe(subscription)