Hist: A Simple Eventstore in Go.

A data store for event sourced applications.

Usage

package main

import (
	"fmt"

	"github.com/robertreppel/hist/filestore"
)

const eventDataDirectory = "/tmp/hist-examples-helloworld"

func main() {
	eventStore, err := filestore.FileStore(eventDataDirectory)
	failIf(err)

	aggregateType := "Customer"
	aggregateID := "12345"
	eventType := "CustomerCreated"
	eventData := []byte("Bill Smith")
	err = eventStore.Save(aggregateType, aggregateID, eventType, eventData)
	failIf(err)

	eventHistory, err := eventStore.Get(aggregateType, aggregateID)
	failIf(err)

	fmt.Printf("Event: '%s' Event data: '%s'\n", eventHistory[0].Type, string(eventHistory[0].Data))
	// Output: Event: 'CustomerCreated' Event data: 'Bill Smith'
}

func failIf(err error) {
	if err != nil {
		panic(err)
	}
}

Full (minimalist) event sourcing example:

cd examples/planets
go get
go build
./planets

File Storage

Events can be stored in files. Each aggregate type is a directory. Each aggregate instance is a file, with events appended when they are saved. For example, given a data directory "/data", a "User" aggregate and a user with id "12345", when an "EmailChanged" event is saved it is appended to "/data/events/User/12345.events"

AWS DynamoDB Storage

Events can be stored in a DynamoDB table. See examples/trackmyships.

Tests

Uses http://goconvey.co/. Run it to see BDD-style details about hist's business rules and behaviour. For the integration tests to pass, a local DynamoDB instance must be running. ( https://aws.amazon.com/blogs/aws/dynamodb-local-for-desktop-development/ )

Production Use

Hist is considered alpha. Not recommended for production use.

Snapshots

Snapshots are not supported at this time.