Initial ecosystem implementation for Go.

[mitchell-as]

CP-1028 Implement Go ecosystem installer in State Tool

$ cat main.go
package main

import "fmt"
import "github.com/google/uuid"

func main() {
  id := uuid.New()
  fmt.Println("UUID: " + id.String())
}
$ cat go.mod
module hello

go 1.24.5

require github.com/google/uuid v1.6.0

Despite the "go: downloading" line, it's downloading from the local filesystem proxy, not the internet.

Note: I patched my local state tool to allow ':' as a namespace separator so I could run this demo. We should prioritize CP-972.

[Naatan]

Much simpler than I was imagining this would be! Hopefully this holds true as we start testing it more thoroughly.

Just some minor churn.

[Naatan]

Jeremy pointed out not every package will have a go.mod, is that a concern here? I vaguely recall something about the go proxy injecting one, which DI is using so maybe it's fine..

[Naatan]

Also is artifact.NameAndVersion() robust enough? Feels a bit risky to assume a 1:1 mapping there. Perhaps we could locate the go.mod file instead? Assuming the answer to my previous question is that it always exists.

[mitchell-as]

Fair points. I've changed this to a list-dir-and-search approach. If go.mod wasn't found, we create one, according to the goproxy protocol.

[Naatan]

Should defer this after its creation so we're also cleaning up on errors.

[mitchell-as]

@Naatan ping