Coasts: Containerized Hosts for Running Multiple Localhost Environments

Coasts is a tool that addresses the challenge of running multiple localhost environments at the same time. Instead of relying on scripted workarounds that become unwieldy with more than a couple of services, Coasts handles port conflicts, secrets, and volume topologies automatically.

How It Works

At its core, Coasts is a Docker-in-Docker solution with a bind mount from the root of your project. This approach means you can run all your agent harness related host-side without needing to configure tools like Codex, Conductor, or Superset to launch shells in containers. Instead, you create a skill file that tells your agent about the coast CLI, enabling it to determine which coast to execute commands against.

Key Features

• Works with or without docker-compose: The source specifically mentions "it works without docker-compose too"
• Dynamic and canonical port mappings: You can have a single instance of your application always available on regular docker-compose routes host-side, while every coast has dynamic ports for services you wish to expose host-side
• Simplifies agent integration: Agents can interact with coasts through the CLI without complex container shell configurations

Practical Applications

If you have a remotely complex docker-compose setup, Coasts is designed for your use case. The tool has been developed with close friends and a couple of companies, and while it's described as "probably a forever work in progress," it's now opening up to a broader community.

The source recommends watching the videos in the documentation, which illustrate both the power of Coasts and the simplicity of its abstraction.