DEV Community

Cover image for Flask CRUD API on AWS
Safeer Mohiuddin for TinyStacks, Inc.

Posted on • Updated on • Originally published at blog.tinystacks.com

Flask CRUD API on AWS

In this article, we’ll deploy the Flask application we created in the previous article on AWS, using:

  • Amazon RDS (Relational Database Service)
  • Amazon ECR (Elastic Container Registry)
  • Amazon ECS (Elastic Container Service)

Video Version:

image.png

Steps

  • Create RDS instance of Postgres
  • Test the RDS instance
  • Clone and build the TinyStacks GitHub repository
  • Create ECR repository
  • Tag the Docker image and push it to the ECR repository
  • Deploy to ECS using the ECR image
  • Test with Postman (and TablePlus)

Create RDS Instance

Go to the AWS Management Consoleonsole and search for RDS:

image.png

Click on Create Database.

image.png

From the list of available options, select:

  • Standard
  • Postgres version 12.5
  • Free Tier (If you’re a new customer or haven’t used RDS before, you can get up to 750 hours of usage free)

image.png

Choose a name for the instance (basically the name of the database), the master username (postgres), and the password (postgres). Confirm the password. (Make sure to use a more secure password in a production environment!)

image.png

You can leave the rest as it is, except for Connectivity:

image.png

We’ll set this up soon.

You can leave the rest as it is. Just double-check that the estimated monthly cost shows "Free Tier" (assuming you still have Free Tier credits). . Note that the cost of RDS instances may vary over time.

image.png

Then click Create Database:

While you wait, click on the database name and on the security group.

image.png

Click on the security group id, then on Edit Inbound rules. This will let us test our database with an external tool. If you want, you can skip this step. If you do, be sure that both the RDS instance and your app are in the same security group.

image.png

Now, add another inbound rule and make the RDS instance accessible:

image.png

Now we are ready to test the RDS instance.

Test the RDS instance

To test the RDS instance, we will use TablePlus, but you can use any tool you want. Alternative tools include:

Create a new PostgreSQL connection:

image.png

Fill in all the information required to connect:

  • host: (the endpoint of the RDS instance)
  • port: 5432
  • username: postgres
  • password: postgres
  • database: postgres

You can disable SSL mode. (But make sure to leave SSL enabled when working in a production environment!)

Click Test Connection. If you see a connection is ok message, you’re good to go. The database is empty for now.

image.png

Clone the repository, change branch, and build the Docker image

Clone the aws-docker-templates-flask repository from Tinystacks:

git clone https://github.com/tinystacks/aws-docker-templates-flask.git
Enter fullscreen mode Exit fullscreen mode

Step into the directory

cd aws-docker-templates-flask
Enter fullscreen mode Exit fullscreen mode

Now, switch your GitHub branch. You can check all the branches with the command git branch -a.

git checkout flask-local-postgres
Enter fullscreen mode Exit fullscreen mode

Then open this folder with your favorite IDE. IF you have Visual Studio code, you can type:

code .
Enter fullscreen mode Exit fullscreen mode

Open a terminal and, in the folder where the docker-compose.yml file is located, type:

docker compose build
Enter fullscreen mode Exit fullscreen mode

ECR

Login into your AWS CLI, using your <AWS_ACCOUNT_ID> and <REGION>:

aws ecr get-login-password --region <REGION> | docker login --username AWS --password-stdin <AWS_ACCOUNT_ID>.dkr.ecr.<REGION>.amazonaws.com
Enter fullscreen mode Exit fullscreen mode

Create a new ECR repository using the prompt. Use your <REGION>:

aws ecr create-repository --repository-name flask-app --region <REGION>
Enter fullscreen mode Exit fullscreen mode

Then you can check the Amazon Console registries on ECR:

image.png

If you click on the repository name, you won’t see any images. That’s what we expect (for now).

image.png

Tag and push the Docker image on ECR

You can use the value <IMAGE_TAG> to create an image with the tag latest.

docker tag pythonapp <IMAGE_TAG>
Enter fullscreen mode Exit fullscreen mode

Now push the image to the ECR repository:

docker push <IMAGE_TAG>
Enter fullscreen mode Exit fullscreen mode

And check the image on the ECR repository:

image.png

ECS

Now, let's deploy our service using Amazon Elastic Container Service (ECS).

Search for ecs on the AWS Management Console:

image.png

Click on Get Started:

image.png

Click on Custom and then click Configure:

image.png

This will let us configure the container task we want to run in our cluster.

Choose:

  • Container name: any you want
  • Image: the <IMAGE_TAG> (latest)
  • Port: 80

Next, in Advanced Configuration add an environment variable as defined in the docker-compose.yml file:

image.png

image.png

For the values here, use:

  • Key: <DATABASE_URL>
  • Value: postgresql://postgres:postgres@<RDS_INSTANCE_IP>:5432/postgres

Remember to replace the database entry with the <RDS_INSTANCE_IP> for your instance. You can find your <RDS_INSTANCE_IP> on TablePlus or RDS.

Leave the rest as it is and click Update.

image.png

On Task definition, click Next:

image.png

Likewise, on Service, click Next:

image.png

On Cluster configuration, define a name for your cluster and click Next:

image.png

You’re all set! !Click Create:

image.png

Creation will take a couple of minutes. Once all the check marks have turned green, click View Service:

image.png

Click on the task and copy its Public IP. We will need that to test our application.

Test With Postman and Tableplus

First, let’s get all the items. If we get an empty list [], it means that the table has been created and we are getting no items. That’s what we expect, since we just created the table with no data.

GET Request at the endpoint: /items

image.png

To create a new item, make a POST request at the endpoint /items:

image.png

Let's create 2 more items:

image.png

image.png

To get a single item, make a GET request, appending the id of the item we want to retrieve at the end of the /items path. For example /items/2 retrieves the item with id = 2.
(Don't mind the body in this request, that was from the last post request.)

image.png

To update an existing item, make a PUT request. Specify the id of the item we want to modify in the url and the new item in the body of the request:

image.png

If we try to GET the item 2 again, we’ll receive the updated item:

image.png

Finally, to delete an existing item - for example, the item with id = 3 - we can make a DELETE quest at the path /items/3:

image.png

If we try to get all the items again, we only get two:

image.png

A final test using TablePlus:

image.png

GitHub Repository (branch: flask-local-postgres): https://github.com/tinystacks/aws-docker-templates-flask.git

TinyStacks powers teams to build faster without abstractions or menial DevOps tasks.
Check TinyStacks

Video Version:
image.png

Top comments (0)