Smapp

A microservice backend written in Go for a social media app.

Table of contents

• Features
• Running the Application
  • Running with Docker Compose
  • Running with Docker Swarm
  • Applying Database Migrations
• Deploying on AWS
  • Creating Infrastructure
  • Deployment

Features

• Signup and login
• Post creation, comment/like functionality and statistics
• Presigned links for the frontend to upload post images
• Following functionality and paginated feed

Running the Application

Whether you want to run the project locally or remotely, first clone the repository:

git clone https://github.com/avoronoi/smapp

Then, generate the Go code for the gRPC client and server from the .proto files. Ensure that you have Go and the Protocol Buffer compiler (protoc) installed. Additionally, install the following packages:

go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest

Then execute:

protoc --go_out=. --go_opt=paths=source_relative --go-grpc_out=. --go-grpc_opt=paths=source_relative common/grpc/user/user.proto 
protoc --go_out=. --go_opt=paths=source_relative --go-grpc_out=. --go-grpc_opt=paths=source_relative common/grpc/image/image.proto 

You will also need to install gomplate, a template renderer that will be used to generate the docker-compose.yml file.

There are two options to run the app: using Docker Compose and Docker Swarm.

Running with Docker Compose

Docker Compose runs only on a single node, so it should only be used for development. It builds images from the services' Dockerfiles and supports rebuilding services on code changes using docker compose watch. The configurations for docker compose watch are specified in the docker-compose.override.yml file.

To run the application, first generate the docker-compose.yml file:

LOCAL=1 gomplate -f docker-compose.yml.tmpl -o docker-compose.yml

Next, create a MySQL root password and store it in the secrets/mysql_password.txt file. Then, create an RSA key pair and store it in the secrets/jwt_private_key.pem and ./jwt_public_key.pem files.

You can customize these locations in the docker-compose.override.yml file.

Running with Docker Swarm

Build and Push Images

Docker Swarm does not build images from Dockerfiles and requires prebuilt images to be stored in a registry.

You can use a container registry like Amazon ECR to store them. If you want to run Docker Swarm locally, you can create a container from Docker's registry:2 image:

docker run -d -p 5000:5000 --name registry registry:2

And then use localhost:5000 as registry.

Generate the docker-compose.yml file:

DEPLOY=1 gomplate -f docker-compose.yml.tmpl -o docker-compose.yml

You should also specify LOCAL=1 if you intend to run Swarm locally.

Next, build and push images to the registry:

docker compose build --push

Run Images on a Swarm

First, initialize the Swarm on one of the nodes with ./deployment/init_swarm.sh. This command initializes the Swarm (making the current node its only member) and sets up Swarm secrets and configs.

Run docker swarm join-token manager or docker swarm join-token worker to get a command for joining the Swarm as a manager or worker, respectively. Execute the generated command on the nodes you want to add.

Some nodes act as gateways. When running on an EC2 cluster, these nodes should be the ones that the Application Load Balancer forwards requests to. To designate a node as a gateway, execute ./deployment/set_gateway.sh on it.

Finally, deploy the application from one of the manager nodes:

./deployment/deploy.sh <REGISTRY_ENDPOINT>

Applying Database Migrations

To apply database migrations, use the Flyway migration tool from within the appropriate container.

From the user-db-migrations container:

flyway -url=jdbc:mysql://user-db:3306/user-db?allowPublicKeyRetrieval=true -user=root -password=$(cat /run/secrets/mysql_password) migrate

From the post-db-migrations container:

flyway -url=jdbc:mysql://post-db:3306/post-db?allowPublicKeyRetrieval=true -user=root -password=$(cat /run/secrets/mysql_password) migrate

Deploying on AWS

Creating Infrastructure

Ensure that you have AWS credentials configured with necessary permissions. Then run:

cd terraform
terraform init
terraform apply

Enter the variable values when prompted. You can also specify them in a terraform/variables.tfvars file (see terraform/variables.tfvars.example).

Deployment

To install the necessary packages, create a Swarm and mark necessary nodes as gateways, run:

terraform output -json | (cd ../deployment; go run ./cmd/install_all/main.go)

Then run ./deployment/scripts/deploy.sh <REGISTRY URL> from one of the nodes.