[BUG] Everything is too slow

[synalice]

If you are having issues with the program's speed (containers take around 5 seconds to be created) — you are not the one. It is being worked on, but for now there doesn't seem to be a solution for this. The issue seems to be somewhere within the Docker API.

A possible workaround would be to pre-create a "pool" of containers, but this seems like a very ugly solution, and it doesn't fix the issue that all other operations on Docker's API take too much time.

[synalice]

Update
The reason why the performance is so bad is mostly due to a config.EnsureImage() method that gets called from the config.NewConfigBuilder.Image().

The reason why calling config.EnsureImage() affects the performance so much is because it calls a docker's API, and doing this always takes a bit of time. But it's not so simple. While all other methods and functions (like ones regarding the removal of volumes and containers) also take some time — config.EnsureImage() is the worst.

config.EnsureImage() is supposed to check if an image you are trying to use for a config already exists on your machine, or if it is absent and needs to be pulled from the registry. Under the hood config.EnsureImage() calls for docker's Client.ImagePull().

The actual problem is that if the image actually does exist, and you don't need to pull it, Client.ImagePull() takes a tremendously long time to finish. At least for me, that seems to be too long for something so trivial — checking if an image is there or not.

For now, I will make it so that config.NewConfigBuilder.Image() doesn't call config.EnsureImage() which means you'll have to make sure that an image you are trying to use actually exists on your machine. Although, it not that big of a deal since you will get an error if an image you are trying to use is not there.

[synalice]

The performance is still not as good as I'd want it to be, but now I understand what is the issue and will try to pay more attention to it.