findMe backend 📟

This repository contains the backend for the findMe application. findMe is a social media platform where users can follow each other and engage in a unique game of location riddles.

In this game, users post photos containing a geolocation. Other users then have to guess as precisely as possible where the photo was taken. The closer the guess, the higher the score. This creates a fun and engaging way for users to test their geographical knowledge and observational skills.

The backend is composed of two microservices:

• findme-location-riddles: Handles the creation and management of location riddles.
• findme-users: Manages user profiles, including follow relationships.

Each microservice is developed using Python, and they are all deployed using Docker and Serverless. The backend API can be accessed locally for development purposes.

Please refer to the sections below for detailed instructions on local development setup, hot reloading, common problems, how to get a token for development, and how to run tests.

Local Development

Prerequisites

• Docker
• LocalStack CLI
• serverless

Setup

1. create a sls-config-local.yml file in the root directory with the following content:

   extensions:
       FindmeDashusersLambdaFunction:
         Properties:
           Code:
             S3Bucket: hot-reload
             S3Key: <absoloute-path-to-repository>/workspace/backend/findme-users
       FindmeDashlocationDashriddlesLambdaFunction:
         Properties:
           Code:
             S3Bucket: hot-reload
             S3Key: <absoloute-path-to-repository>/workspace/backend/findme-location-riddles

   verify that the paths are absolute and point to the correct directories
2. install all serverless dependencies with npm install in the root directory
3. using python3.12 create a virtual environment inside each microservice directory py running python -m venv .venv
4. activate the environment to use the local project pip and python
5. install dependencies with:
   1. pip install -r requirements.txt --platform manylinux2014_x86_64 --only-binary=:all: -t .venv/lib/python3.12/site-packages
6. start the localstack container with localstack start
7. run sh deploy.sh --stage local to deploy the services (or sls deploy --stage local first in the /infrastructure directory and then in the root directory)
8. access the backend API on http://localhost:4566/restapis/findme/local/user_request/
9. add new dependencies by extending the requirements.txt file in the microservice directory

Hot reloading

With this setup the lambda functions are configured to automatically hot reload. This means that if you perform a change in e.g findme-users/ you will see the change after saving without redeploying.

Common Problems

• verify that you're using the specified python version to create the virtual environment
• double-check the absolute path in the sls-config-local.yml file
• The properties in the sls-config-local.yml file have to be named exactly like serverless names the cloudformation resources, double-check that the names match to the ones in .serverless/cloudformation-template-update-stack.json

Testing

⚠️ Caution: We have to use a different virtual environment while testing as during the setup, because we run the tests locally on our device and do not mount them into the lambda function. To do this either create a seperate venv outside or replace the one inside the microservice directory.

python -m venv .venv

.venv/bin/pip install -r <path_to>/requirements.txt

To run the tests for the microservices, run python -m unittest discover from the backend root. (If the virtual environment hasn't been activated yet, you can do so by running the command source .venv/bin/activate.) For generating a test report, execute the generateTestReport.py script.

Token

To get a token for developing use the following curl command:

curl --request POST \
  --url https://findme-dev.eu.auth0.com/oauth/token \
  --header 'content-type: application/json' \
  --data '{"client_id":"0FhpaZeIjhSG1lwNR3RWPI20VgLgU5rk",
            "client_secret":<client_secret>,
            "audience":"https://findme-dev.eu.auth0.com/api/v2/","grant_type":"client_credentials"}'

Documentation

For the detailed api documentation start the application as described above and visit the following endpoints:

• {your_application_url}/users/swagger
• {your_application_url}/location-riddles/swagger

Tips and Tricks

This file is a collection of useful tips and tricks which facilitate the development process.

Inspecting table content

• By running awslocal dynamodb scan --table-name FollowerTable --region eu-central-2 in the terminal, one can inspect the FollowerTable content
• By running awslocal dynamodb scan --table-name usersTable --region eu-central-2 in the terminal, one can inspect the FollowerTable content