Do not use `fork()` when concurrency is `1`

[CumpsD]

Checklist

• [x] Upgrade Terraspace: Are you using the latest version of Terraspace? This allows Terraspace to fix issues fast. There's an Upgrading Guide: https://terraspace.cloud/docs/misc/upgrading/
• [x] Reproducibility: Are you reporting a bug others will be able to reproduce and not asking a question. If you're unsure or want to ask a question, do so on https://community.boltops.com

My Environment

Software	Version
Operating System	Windows
Terraform	1.1.5
Terraspace	1.1.2
Ruby	3.1.0

---

Expected Behaviour

Running an all command on Windows should work.

Current Behavior

all commands do not work because fork() does not exist on Windows

terraspace all show
Running:
    terraspace show backend # batch 1
Batch Run 1:
C:/Ruby31-x64/lib/ruby/gems/3.1.0/gems/terraspace-1.1.2/lib/terraspace/all/runner.rb:44:in `fork': fork() function is unimplemented on this machine (NotImplementedError)

Setting config.all.concurrency = 1 still uses fork, so cannot be used as a workaround.

Solution Suggestion

Find a way to make fork() work on Windows, or skip fork() when concurrency is set to 1

[tongueroo]

Done in #207

Had some mixed feelings here and almost did not do this. Some thoughts:

Not forking when config.all.concurrency = 1 seems like a simple way to address this, but has it's own issues:

• The code structure with the conditionals is not as generalize. The code is tougher to reason. Have written much worst code before 🤣 But when it comes to forking try to keep it clean because parallelization makes things already harder to follow.
• Had to disable summarized logging when config.all.concurrency = 1. This is because summarized logging leverages how forking works.
• Disabling summarize could be pro or con. Think it maybe depends on personal preference. 🤔
• Generally like consistent behavior. IE: It does what you expect it to do. The default probably should be summarized logs.
• This works for now. May change it though. 🧐

Would like to try getting "Windows forking" working. Here's some starter research.

• Windows Docs: CreateProcessA function
• StackOverflow: forking() and CreateProcess()

[CumpsD]

I understand your reasoning behind keeping the code simple, and agree completely :) I hope you find a clean way 🤞🏻