Introducing spin terminal plugin

In this blog, I will explain the new spin terminal plugin, and how it helps with the local DX.

Disclaimer: This is not an official plugin. I wrote this plugin as a personal project.

tl;dr;

Use spin terminal to set up a local container with the required toolchains installed:

spin new -t http-go terminal-demo --accept-defaults

cd terminal-demo

cat >> .toolchains<<EOF
golang=1.23.2
tinygo=0.34.0
spin=canary
EOF

spin plugin install -u https://github.com/rajatjindal/spin-plugin-terminal/releases/download/canary/terminal.json
spin terminal

$ go version
1.23.2

$ tinygo version
0.34.0

$ spin --version
spin 3.1.0-pre0

Why

The WebAssembly ecosystem is moving very fast, and every week there are new releases for tooling as the community adds new features. While this is great, it also sometimes creates problems. e.g.

I was working on one of my old projects and was trying to fix a bug in it. Bug fixing was easy, but now to make sure I can test it on my local setup, I needed a specific version of tinygo, which further needs a specific version of golang. While the CI is set up to install specific versions in GitHub actions, the toolchain on my dev box has already evolved to the latest and greatest versions.

🎉 Enter spin terminal 🎉

Spin Terminal

spin terminal is a plugin that helps set up the toolchain required for working on a spin app. It leverages programmable modules provided by dagger using which one can selectively build up a container image with the tooling that can be selected at runtime.

While one can argue that this is possible with Dockerfile as well (and as almost everyone I have used Dockerfile for setting up similar projects). While it works, the resulting Dockerfile is not very readable.

spin terminal is essentially a sugar wrapper on top of the dagger call command. You can read more about that here.

Installing it

You can install the spin terminal plugin using the following command:

$ spin plugin install -u https://github.com/rajatjindal/spin-plugin-terminal/releases/download/canary/terminal.json
You are trying to install the `terminal` plugin with Apache-2.0 license from
https://github.com/rajatjindal/spin-plugin-terminal/releases/download/canary/spin-plugin-terminal-canary-darwin-arm64.tar.gz
Are you sure you want to continue? yes

Plugin 'terminal' was installed successfully!

Description:
 A plugin to provide a terminal for the toolchain required by spin app

Homepage:
 https://github.com/rajatjindal/spin-plugin-terminal

How to use it

The spin terminal expects a .toolchains file in the current directory with name=version format. e.g.

spin=3.0.0
golang=1.23.2
tinygo=0.34.0

Now when we trigger spin terminal command, it reads that file and sets up a container with those toolchains installed. e.g.

$ cat .toolchains 
spin=canary
golang=1.20.14
tinygo=0.30.0
rust=1.82.0

$ spin terminal
dagger /app $

dagger /app $ spin --version
spin 3.1.0-pre0 (509d8d1 2024-11-13)

dagger /app $ go version
go version go1.20.14 linux/arm64

dagger /app $ tinygo version
tinygo version 0.30.0 linux/arm64 (using go version go1.20.14 and LLVM version 16.0.1)

dagger /app $ cargo --version
cargo 1.82.0 (8f40fc59f 2024-08-21)

This is it. Let me know if you find this plugin to be useful and star the repo.

Ask me how I can help you leverage the bleeding edge technologies such as dagger, webassembly, spin for scaling your services and infrastructure and improve productivity of your teams.