mirror of
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133 lines
3.7 KiB
Markdown
133 lines
3.7 KiB
Markdown
# Microservices
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A basic example of microservice architecture which demonstrates communication between a few loosely coupled services.
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* Written in Go
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* Uses RabbitMQ to communicate between services
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* Uses WebSocket to talk to the front end
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* Stores data in PostgreSQL
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* Stores cache in Redis
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* Uses React for front end development
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* Builds with Docker
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* Deployed as containers on AWS
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## Local use
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To run the example, clone the Github repository and start the services using Docker Compose. Once Docker finishes downloading and building images, the front end is accessible by visiting `localhost:8080`.
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```bash
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git clone https://github.com/ebosas/microservices
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cd microservices
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```
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```bash
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docker-compose up
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```
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### Database
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To inspect the database, launch a new container that will connect to our Postgres database. Then enter the password `demopsw` (see the `.env` file).
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```bash
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docker run -it --rm \
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--network microservices_network \
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postgres:13-alpine \
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psql -h postgres -U postgres -d microservices
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```
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Select everything from the messages table:
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```sql
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select * from messages;
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```
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### Redis
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To inspect Redis, connect to its container via redis-cli.
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```bash
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docker run -it --rm \
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--network microservices_network \
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redis:6-alpine \
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redis-cli -h redis
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```
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Get all cached messages or show the number of messages.
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```bash
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lrange messages 0 -1
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get total
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```
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### RabbitMQ
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Access the RabbitMQ management interface by visiting `localhost:15672` with `guest` as both username and password.
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### Back end
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To access the back end service, attach to its docker container from a separate terminal window. Messages from the front end will show up here. Also, standart input will be sent to the front end for two way communication.
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```bash
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docker attach microservices_backend
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```
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## Deployment to Amazon ECS/AWS Fargate
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`cd deployments` and create the CI/CD pipeline stack. Once finished, visit the `ExternalUrl` available in the load balancer's Outputs tab in CloudFormation.
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```bash
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aws cloudformation create-stack \
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--stack-name MicroservicesFargate \
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--template-body file://pipeline.yml \
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--parameters \
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ParameterKey=DeploymentType,ParameterValue=fargate \
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ParameterKey=EnvironmentName,ParameterValue=microservices-fargate \
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ParameterKey=GitHubRepo,ParameterValue=<github_repo_name> \
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ParameterKey=GitHubBranch,ParameterValue=<github_branch> \
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ParameterKey=GitHubToken,ParameterValue=<github_token> \
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ParameterKey=GitHubUser,ParameterValue=<github_user> \
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--capabilities CAPABILITY_NAMED_IAM
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```
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### Github repo setup
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Fork this repo to have a copy in your Github account.
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Then, on the [Github access token page](https://github.com/settings/tokens), generate a new token with the following access:
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* `repo`
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* `admin:repo_hook`
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### Deleting stacks
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When deleting the ECS cluster stack (`cluster-ecs.yml`) in CloudFormation, the auto scaling group needs to be manually deleted. You can do it from the Auto Scaling Groups section in the AWS EC2 console.
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With capacity providers, container instances need to be protected from scale-in. This interferes with the automatic deletion process in CloudFormation.
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### References
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Deployment is based on these templates: https://github.com/nathanpeck/ecs-cloudformation
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## Local development
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For development, run the RabbitMQ and Postgres containers with Docker Compose.
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```bash
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docker-compose -f docker-compose-dev.yml up
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```
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Generate static web assets for the server service by going to `web/react` and `web/bootstrap` and running:
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```bash
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npm run build-server
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```
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### React
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For React development, run `npm run serve` in `web/react` and change the script tag in the server's template to the following:
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```html
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<script src="http://127.0.0.1:8000/index.js"></script>
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```
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