Why is .withReuse(true) not the default?

[wimdeblauwe]

I wonder why there are 2 things you need to do to get container re-use: set the property in your home directory + add .withReuse(true) in the Java code itself. It seems like this could be the default as it would only kick in if you have that property in your home directory anyway. Or are there potential pitfalls I need to be aware of that made you decide not to make that the default?

[kiview]

Hey @wimdeblauwe, happy to hear that you seem to like withReuse so much, you could imagine it being the default 🙂

Reusable containers is still an alpha feature with only experimental support, so we currently want to make the opt-in very explicit. In addition, withReuse indicates if a container can be reused in the context of its creation (or its test), while the flag in .testcontainers.properties indicates that the runtime environment would benefit from reuse (e.g. we generally don't want CI to use reuse).

Still thanks for your comment, we will consider the different UX aspects once we move forward in making this feature GA 👍

[wimdeblauwe]

Thanks for clarifying this. To be clear: I have not used it yet, because the fact it is not the default made me hesitant to start using it. But as you point out, as long as the CI does not have that properties file, there is nothing that can go wrong as it would not kick in anyway there.

[bsideup]

Not every container is reusable. For example, if you set an environment variable to something random, it will always start a new container.

withReuse is your "opt-in" way of saying that "yes, X can be reused", and the property in testcontainers.properties says that "yes, this environment should reuse containers".