Use cases

• Got a script that you want to be able to run multiple instances of in parallel?
• Want to write a program from scratch that's ready to scale up?
• Using someone else's code that has race conditions and want to singleton-ize it?

Intro

Hungry Hungry Hippos, (HHH) is a python implementation of redlock https://redis.io/topics/distlock with a set of examples that use docker, redis and docker compose. The advantage of this approch, compared to multithreading, is that is can be applied in a single-threaded context (for example if you have to integrate existing code), or in a mutliple container instance context (think microservices)

Features

• atomic locking guarantees single lock acquisition
• works across machines / containers
• handles dead lock recovery
• can wrap existing code for cases when you cannot or do not want to do a rewrite.

Key concepts

• Process isolation
• Destributed locks (see https://redis.io/topics/distlock)
• Command orchestration

Toolchain

• docker - images, containers, volumes
• docker-compose - building, linking services, scaling services
• redis - in memory key-value database

Installation

pip install hungry-hungry-hippos

See examples for use cases