Object Store API

This application provides a simple API for storing your data in your key-value store with history.

Installation

Prerequisites:

• PHP 7.4+ with pdo_mysql and redis extensions
• Composer
• MariaDB or MySQL server
• Redis server

composer install # Install dependencies
bin/console doctrine:migrations:migrate -n

Note that you may need to update your DB and Redis credentials. Simply put DATABASE_URL=mysql://admin:[email protected]/object_store in .env.local and put your credentials there.

Usage

Application offers both Web and CLI interfaces.

Web

The easiest way to run the application is by installing Symfony CLI and run:

symfony serve

Your app should be available at http://localhost:8000.

Use provided Swagger UI documentation to browse the API.

CLI

Application offers two CLI commands:

bin/console app:object-store:store <key> <value> # Stores the value in object store
bin/console app:object-store:get <key> [-t TIMESTAMP] # Gets the value from object store at given time

Please note that value must me JSON-encoded and escaped for your terminal. For example, if you want to store a string value: test-value at key test-key, you have to use following command:

bin/console app:object-store:store test-key \"test-value\"

This is to enable you to store complex data as a value.

Storage adapters

Application allows you to easily swap between different implementations of storage drivers. You can easily create one by implementing App\Infrastructure\ObjectStorage\ObjectStorageAdapter interface and tagging your service with object_storage.adapter tag (see example in config/services.yaml file).

Currently implemented drivers are:

• DoctrineObjectStorageAdapter - stores data in Database
• RedisObjectStorageAdapter - stores data in Redis

Choosing the adapter

To change the adapter, simply set STORAGE_ADAPTER environment variable to redis or doctrine:

# /.env.local
STORAGE_ADAPTER=redis

Doctrine

DoctrineObjectStorageAdapter uses Doctrine ORM to store data as ObjectEntry entities.

The ObjectEntry entity is using VARCHAR(255) column type.

• utf8mb4 character set for full Unicode support so you can use keys like 🧅 or 😃.
• utf8mb4_bin collation ensures binary comparison of keys so KEY !== key and key !== kęy.
• Timestamp is stored as TIMESTAMP in UTC

Limitations

Because of MySQL index length limitations, an error may occur when storing bigger keys.

Redis

RedisObjectStorageAdapter uses Redis as storage using sorted sets. Internally, the sorted set keeps only the change reference as:

KEY	VALUE	SCORE
key	SHA512(key):timestamp	timestamp

Then, the actual value is stored in a hashmap as:

KEY	VALUE
SHA512(key):timestamp	value

Because sorted sets require values to be unique, this approach allows value1 -> value2 -> value1 transitions to be properly stored.

Limitations

Since the implementation uses SHA512 as part of the key, some conflicts may occur.

Tests

All components are covered by either unit or feature tests.

Running tests is as simple as configuring .env.test.local variables to match your DB credentials and running:

bin/phpunit

Mutation tests

To make sure your tests actually have necessary assertions, CI is running mutation tests using Infection.

Make sure you have Xdebug or PCOV extension enabled as it is required to run:

vendor/bin/infection

Deployment

This application is being automatically tested using GitHub Actions and deployed on Heroku.