Migrating to Modules in Hugo

Go introduced modules several years ago as part of a dependency management system. My Hugo site is still using git submodules to manage its theme. I attempted to migrate to Go’s submodules but eventually ran into a snag when trying to deploy the site.

To start, remove the submodule

git submodule deinit --all

and then remove the themes folder

git rm -r themes

To finish the cleanup, remove the theme key from config.toml.

Next, setup the project to use modules

go mod init github.com/danielcorin/blog

and added the theme as a module to the config.toml

[module]
[[module.imports]]
  path = 'github.com/lukeorth/poison'

To update the go.mod file, run

hugo mod get -u

which should add the module to the go.mod file

module github.com/danielcorin/blog

go 1.19

require github.com/lukeorth/poison v0.0.0-20230630204947-22c6c4aba785 // indirect

Running hugo serve and hugo --gc should both still work.

I pushed this changed but it failed to build on Vercel, where I have my site deployed. It looks like go isn’t available during build time

Running "vercel build"
Vercel CLI 31.0.1
Installing Hugo version 0.110.0
Error: failed to download modules: binary with name "go" not found
Total in 0 ms
Error: Command "hugo --gc --minify --ignoreCache --verbose" exited with 255
BUILD_UTILS_SPAWN_255: Command "hugo --gc --minify --ignoreCache --verbose" exited with 255

I may return to this though I do have some concerns about whether fixing the issue will increase build time, which is something I’d like to avoid.