Trigger an accompanying docker-compose file

[CLOVIS-AI]

(this is an idea that was thrown around while discussing other things; I'm creating an issue to have a central place to discuss it)

Websites will often need some accompanying services, for example Keycloak (identity manager), MongoDB/Postgres/… (databases), caches.

It'd be great if the CLI could auto-start and auto-stop them.

To avoid Kobweb having to explicitly handle each possible case, we can rely on Docker.

Example scenario

File structure:

project/
    site/
        …
        build.gradle.kts
    services/
        docker-compose.yml

Contents of docker-compose.yml:

name: MyApp

services:
  mongo:
    image: "mongo:7.0.31"
    ports:
      - "27017:27017"

When I run kobweb run, the CLI should discover that the services are declared, and start them. kobweb stop should stop them.

Implementation details

On start, run in the directory in which the docker-compose.yml is:

• docker compose build: If the docker-compose.yml references custom Dockerfiles, this ensures they are rebuilt. If it doesn't, this is a no-op (docker prints a warning about it being a no-op).
• docker compose up -d: Downloads & starts all services.

On stop, run in the directory in which the docker-compose.yml is:

• docker compose down: Stops everything and frees resources

Possible failures

User doesn't have docker installed. Warn the user that the services couldn't be auto-started.

Crash when calling docker: for security reasons, docker may be installed but the current user may not be allowed to access it. Warn the user that the services couldn't be auto-started.

A growing alternative to Docker is Podman, which accepts the exact same commands, maybe users should be able to configure which one they want to use?

[bitspittle]

Higher level question is if the CLI should handle it or if the Kobweb Gradle plugin should do it.

If I run ./gradlew kobwebStart manually, and later run ./gradlew kobwebStop, shouldn't that also work?

Now that I think about it, since this is Gradle we're talking about, maybe this is as simple as adding the logic into the build script and hook it up to the existing start and stop tasks (kobwebStart { doFirst { ... } }, kobwebStop { doLast { ... } }). So, we might not need to do anything in the CLI.

The more I think about it, the more I think the way forward here is to expose a friendly API from the Kobweb plugin which lets you add preStart and postStop hooks.

Finally... note that, even if this were all working, the user would still need to install / run docker first. So it's still not just a simple "kobweb run without thinking about it" solution.

[CLOVIS-AI]

Finally... note that, even if this were all working, the user would still need to install / run docker first.

Indeed. I don't think it's possible to do much better than that, and it's fairly standard in the ecosystem (e.g. testcontainers has the same requirements).

[CLOVIS-AI]

Yeah, putting that logic in the Gradle plugin is probably easier.