README

Installation

composer require proophsoftware/mongo-read-event-store

Purpose

The package provides a read-only mongodb event-store that connects to a prooph/event-store v6 mongodb. Fetched events are upcasted on-the-fly so that they fit into the message format defined by prooph/common v4 and up. The read-only mongodb event-store can be used to migrate v6 mongodb event streams to prooph/event-store v7 event-streams using a stream-to-stream projection.

Furthermore, you can use the read-only mongodb event-store within the event-store-http-api project to read your v6 event streams via HTTP.

Limitations

With prooph/event-store v7 a new event stream position was introduced which is a sequence. This new position is addressed in the EventStore::load and EventStore::loadReverse methods, but a v6 stream does not have such a position. Therefor, we fall back to sort by created_at and use $fromNumber - 1 as skip option. This emulates iterating an event stream but may return a different event order as they were recorded due to same timestamp.

Event Store HTTP API

To use the read-only mongodb event store with the event-store-http-api you need to wrap it with the DecoratedReadOnlyEventStore ship with this package because the http api package requires a full event store implementation. This means that you cannot use write actions of the http api.

Indexing

To efficiently sort events by created_at you should add an index to your stream collections:

$collection->createIndex([
    'created_at' => 1
], ['name' => 'prooph_rom_sort']);