4.2. Changing Event Store

AWS DynamoDB

To use AWS DynamoDB event store we need to add localstack container. This way we can use a fully functional local AWS cloud stack.

helm/requirements.yaml

dependencies:
+# AWS localstack (for local development)
+  - name: microservice
+    version: 0.1.0
+    repository: "file://../microservice"
+    alias: localstack
+    condition: localstack.enabled

helm/values.yaml

ingress:
  paths:
+    - path: /localstack
+      backend:
+        serviceName: go-api-boilerplate-localstack
+        servicePort: 4567

+ # AWS localstack https://github.com/localstack/localstack
+ localstack:
+   enabled: true
+   nameOverride: localstack
+   image:
+     repository: localstack/localstack
+     tag: 0.8.10
+     pullPolicy: IfNotPresent
+   service:
+     ports:
+       - name: dynamodb
+         internalPort: 4569
+         externalPort: 4569
+       - name: ui
+         internalPort: 4567
+         externalPort: 4567
+   env:
+     - name: SERVICES
+       valueFrom: "dynamodb:4569"
+     - name: PORT_WEB_UI
+       valueFrom: 4567

user:
  env:
+    - name: AWS_REGION
+      valueFrom:
+        configMapKeyRef:
+          key: AWS_REGION
+          name: go-api-boilerplate-app
+    - name: AWS_ENDPOINT
+      valueFrom:
+        configMapKeyRef:
+          key: AWS_ENDPOINT
+          name: go-api-boilerplate-app

configMap:
  data:
+    AWS_REGION: 'us-east-1'
+    AWS_ENDPOINT: 'http://go-api-boilerplate-localstack:4569'

Finally we can switch memory event store to DynamoDB one as follow:

cmd/user/main.go

package main

import (
+	"github.com/aws/aws-sdk-go/aws"
-	"github.com/vardius/go-api-boilerplate/pkg/eventstore/memory"
+	"github.com/vardius/go-api-boilerplate/pkg/eventstore/dynamodb"
)

type config struct {
+	AwsRegion   string `env:"AWS_REGION"   envDefault:"us-east-1"`
+	AwsEndpoint string `env:"AWS_ENDPOINT" envDefault:"http://localhost:4569"`
}

func main() {
	ctx := context.Background()

	cfg := config{}
	env.Parse(&cfg)

+	awsConfig := &aws.Config{
+		Region:   aws.String(cfg.AwsRegion),
+		Endpoint: aws.String(cfg.AwsEndpoint),
+	}

-	eventStore := eventstore.New()
+	eventStore := eventstore.New("events", awsConfig)