ASDF & direnv demo

Per project tooling

The go directory has the .envrc and .tool-versions files in place to use a specific version of golang and golangci-lint.

To install asdf all tools defined in .tool-versions:

$ cd go 
$ make setup

To uninstall asdf and reset your env:

$ cd go
$ make teardown

Every time a .envrc file is modified you must explicitly allow it to run. This is to avoid security issues from a sneaky modification

$ cd go
direnv: error <path>/asdf-demo/go/.envrc is blocked. Run `direnv allow` to approve its content
$ direnv allow

If you change the list of asdf plugins (the helpers for each tool that know how to fetch & install versions) and specific tool versions specified in .tool-versions

$ make install

Now you should have the versions in your path

$ go version
go version go1.18.3 darwin/arm64
$  golangci-lint version
golangci-lint has version 1.46.1 built from 044f0a17 on 2022-05-12T09:23:45Z

If you leave this directory then the tools will no longer be in your path. Note that you get some helpful explanation from asdf though

$ cd ..
direnv: unloading
$ golangci-lint version
No version is set for command golangci-lint
Consider adding one of the following versions in your config file at $HOME/.tool-versions
golangci-lint 1.46.1

Other useful features

Dynamically changing path / setting ENV variables

$PATH is dynamically changed depending on the plugins you use in the .tool-versions file. For example, as we are using the golang plugin then both $GOPATH and $GOROOT is exported to our environment, and also $GOPATH is added to our $PATH. For example

$ cd go 
......
direnv: export +GOPATH +GOROOT +MIX_ARCHIVES +MIX_HOME ~PATH

# Lets install a handy go binary
$ go install github.com/rakyll/hey@latest
.......

# Is that in our path ?
$ type hey
hey is /Users/jon/.asdf/installs/golang/1.18.3/packages/bin/hey

# Lets use it
$ hey https://www.bbc.co.uk

And when you leave that directory the changes to your environment are undone

Running tools from IDEs / elsewhere

If you want to run the exact same tools as you've set up from other locations / programs you can use the direnv exec command. For example

$ cd $HOME
$ direnv exec <path to checkout>/asdf-demo/go golangci-lint version

Further reading

More useful pro-tips

go2

The go2 folder is just a small update on the go folder contents. The install script and the root's .tool-versions are two files that would be dropped into a project and run using a project's Makefile or called directly.

I would like feedback on these changes to the go folder.