Surveys

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Surveys Data source
Results(PDF)

Exercice

Handling 2022 presidential election surveys results and displaying data as follow:

|               | Candidate 1 | Candidate 2 | ...         |
|---------------|-------------|-------------|-------------|
| Survey 1 Date | Result in % | Result in % | Result in % |
| Survey 2 Date | Result in % | Result in % | Result in % |
| ...           | Result in % | Result in % | Result in % |
Last update: {date}

Init

Copying environments variables

cp .env.example .env

Installing dependancy

docker run --rm \
    -u "$(id -u):$(id -g)" \
    -v $(pwd):/var/www/html \
    -w /var/www/html \
    laravelsail/php81-composer:latest \
    composer install --ignore-platform-reqs

Building project

./vendor/bin/sail up -d --build
./vendor/bin/sail php artisan key:generate
./vendor/bin/sail php artisan config:cache
./vendor/bin/sail php artisan migrate
./vendor/bin/sail php artisan surveys:refresh

Go to http://localhost

Unit tests:

./vendor/bin/sail test

Implementation

Data Modeling

This application handles surveys data through a many-to-many relationship:
one or many surveys records are related to one or many candidates records through a joining table,
which is keeping relationnal data.

Data refresh

In order to replicate a real environment, a scheduled task has been implemented.

Data refreshing is handled through an artisan command: surveys:refresh.
Its job is to fetch fresh data, and managing synchronization accross the database.

For demo purpose, a cron task is scheduled to execute every minute in dev environment.
As the data are not often updated, a production environment should perform this action less frequently.

To simulate scheduler locally:

sail php artisan schedule:work

Or perform the update on demand:

sail php artisan surveys:refresh

Performances

Caching

In order to get best performances results and minimizing data computation frequency, this application should be deployed alongside a web server page caching solution as NGINX or APACHE could do.

Going further

Cloud database read/write operations cost
Data Compute using third party API with limited rates
SPOF webserver caching solution

Misc

Cache exploration

Using redis commander at http://0.0.0.0:8081/

Resolving mysql error 'caching_sha2_password'

docker-compose exec mysql bash

mysql -u root -p
password 

GRANT ALL PRIVILEGES ON *.* TO 'sail'@'%';
ALTER USER 'sail'@'%' IDENTIFIED WITH mysql_native_password BY 'password';

antoine-federici/president