Sandboxes

I'm a big fan of interactive playgrounds. So today I'm open sourcing 30+ sandboxes — from programming languages to databases to networking and CLI tools. You can use them to experiment locally, or embed interactive examples in your writing like this:

// Java 23

void greet(String name) {
    System.out.println("Hello, %s!".formatted(name));
}

void main() {
    greet("World");
}

Hello, World!

Just look at this Java code, where did all that public-static-class stuff go? Is this even legal? :)

Or like this:

-- ClickHouse 24.8

create table data (id UInt32, x UInt32)
engine MergeTree order by id sample by id
as

select number+1 as id, randUniform(1, 100) as x
from numbers(10000);

select
  avg(x) as "avg",
  round(quantile(0.95)(x), 2) as p95
from data
sample 0.1;

┌─────avg─┬─p95─┐
│ 49.9294 │  95 │
└─────────┴─────┘

Having a sampling feature in your SQL is really nice, isn't it?

What is a sandbox

Sandbox = image + box + commands:

• Image as a Docker image containing specific software, like a compiler or a database engine.
• Box is a configuration for running a container: cpu and memory restrictions, network, mounts, etc.
• Commands are predefined actions you can run in a container.

For example, here is a MariaDB sandbox:

mariadb.tar.gz
├── server
│   ├── Dockerfile
│   ├── database-create.sh
│   ├── database-drop.sh
│   └── init.sql
├── client
│   └── Dockerfile
├── box.json
├── commands.json
├── build.sh
└── setup.sh

You run sandboxes with Codapi (a lightweight sandbox server, essentially a thin layer on top of Docker/Podman).

To add a sandbox, run ./codapi-cli sandbox add <name> like this:

./codapi-cli sandbox add lua
./codapi-cli sandbox add go
./codapi-cli sandbox add mariadb

...and you are good to go.

See github.com/nalgeon/sandboxes for details.

Supported languages and software

Programming languages:

Bash        JavaScript      Raku
C           Kotlin          Ruby
C#          Lua             Rust
C++         Odin            TypeScript
Elixir      PHP             V
Go          Python          Zig
Java        R

Databases:

chDB            MySQL
ClickHouse      PostgreSQL
DuckDB          SQL Server
MariaDB         SQLite
MongoDB

Networking and tools:

Caddy       Grep        ...and a ton of others
Curl        Hurl
Git         Ripgrep

Feel free to contribute new sandboxes or ask me to do so.

Final thoughts

Personally, I use these sandboxes all the time to write blog posts and interactive books. I hope you'll find them useful too!

See the nalgeon/sandboxes repo if you are interested.

★ Subscribe to keep up with new posts.