If you’re using CodeSandbox SDK, there’s a big chance that you want to customize the base environment of your sandboxes. You might want to preload a custom Docker image, or prestart a server that should be available as soon as you create a sandbox.
You can use our CLI to create a memory snapshot that has all this data preloaded. This CLI will build a sandbox based on a folder, load the docker image, start the servers and finally create a memory snapshot that can be used when creating new sandboxes.
New sandboxes can be created from this memory snapshot, which means that new sandboxes will “hit the ground running” with the servers running during snapshot creation. Creating a sandbox from a memory snapshot takes 1-3 seconds.
Install the CodeSandbox SDK CLI:
npm i -g @codesandbox/sdk@latest
Then create a directory with the files you want to have available inside your sandboxes.
Finally, run:
$ CSB_API_KEY=KEY csb build <path>
abcde1
This will create a fresh sandbox, upload the files, start all necessary servers and finally snapshot the sandbox to return the id you can use. You can then pass this id when creating new sandboxes:
const sdk = new CodeSandbox(process.env.CSB_API_KEY);
const sandbox = await sdk.sandbox.create({ template: 'abcde1' });
CodeSandbox uses Dev Containers for configuring Docker or Docker Compose for an environment. You can configure Docker by creating a .devcontainer/devcontainer.json file inside your snapshot folder with these contents:
{
"image": "ubuntu:22.04"
}
When we boot the sandbox, we’ll make sure that the docker image is pulled (or built) and we’ll make sure that all shells will start within this container. The /project/sandbox folder is mounted inside the container.
You can also decide to build the Docker image as part of the snapshot creation process. You can do this by defining this in your .devcontainer/devcontainer.json:
{
"build": {
"dockerfile": "Dockerfile"
}
}
And creating a .devcontainer/Dockerfile with the contents of your Dockerfile.