Put dnsmasq config files in /opt/homebrew/etc

[KludgeKML]

Why

On M1 machines, even when you can get an app running in govuk-docker, you can't currently access it via the .dev.gov.uk hostname in your browser.

What's the problem

We're using dnsmasq to resolve those hostnames into 127.0.0.1, which the nginx-docker proxy then picks up and routes to the backing app. The existing bin/setup script puts the configuration files for dnsmasq in /usr/local/etc. But on M1 machines /usr/local/etc doesn't exist, and homebrew dnsmasq looks in /opt/homebrew/etc, where the dnsmasq config files and directories already exist. This change updates those paths in bin/setup.

Any other notes

This problem wasn't caught by Doctor, which only checks:

• is dnsmasq running
• does the first config file (/etc/resolver/dev.gov.uk) exist?
  ..in this case, both of those were true, but without the other two config files nothing would work. We could perhaps update doctor to make an actual dns request (via dig maybe?) to check that the configuration is working as expected.

[Tetrino]

Looks great for now - hopefully we can do some architecture sniffing in the future but let's get this running first.

[ollietreend]

I think it should be possible to make this cross-architecture compatible by using brew --prefix instead of hardcoding the path:

Suggested change

	echo -e "✅ Configuring dnsmasq [/opt/homebrew/etc/dnsmasq.conf]\n"
	echo -e "✅ Configuring dnsmasq [$(brew --prefix)/etc/dnsmasq.conf]\n"

[KludgeKML]

Ooh, interesting. I'd assumed we'd do a bit of cross-architecture sniffing when we merged into full main, but this is very low-cost, worth doing now. I'll update and confirm it works on this machine, if someone else can then try it on an intel machine.

[kevindew]

Thanks @KludgeKML ⭐

I wonder if we can make this support both M1 and Intel, so it can be merged in earlier?

E.g. in my pseudo bash

if intel homebrew directory exists 
  echo -e "✅ Configuring dnsmasq [/usr/local/etc/dnsmasq.conf]\n"
  echo "conf-dir=/usr/local/etc/dnsmasq.d,*.conf" > /usr/local/etc/dnsmasq.conf
  
  echo -e "✅ Configuring dnsmasq [/usr/local/etc/dnsmasq.d/development.conf]\n"
  mkdir -p /usr/local/etc/dnsmasq.d
  echo "address=/dev.gov.uk/127.0.0.1" > /usr/local/etc/dnsmasq.d/development.conf
else 
  echo -e "✅ Configuring dnsmasq [/opt/homebrew/etc/dnsmasq.conf]\n"
  echo "conf-dir=/opt/homebrew/etc/dnsmasq.d,*.conf" >> /opt/homebrew/etc/dnsmasq.conf
  
  echo -e "✅ Configuring dnsmasq [/opt/homebrew/etc/dnsmasq.d/development.conf]\n"
  echo "address=/dev.gov.uk/127.0.0.1" > /opt/homebrew/etc/dnsmasq.d/development.conf
fi

Edit: ooh @ollietreend's suggestion is better

[KludgeKML]

@ollietreend 's change made, confirmed works on M1 machine.

[kevindew]

Great @KludgeKML could we branch this to go into the main branch instead of the M1 one? I imagine we only want to use that branch for anything that isn't interoperable.

[KludgeKML]

@kevindew I can either change this PR to main, or I can close it and reopen on main (maybe with the 3 commits squished into one?). What's the usual preferred option?

[kevindew]

@KludgeKML I'd change the base of this PR to main (can be done by hitting edit in the top right corner if you're not already aware).

[KludgeKML]

Ug, rebase squash has interacted oddly with this PR. Going to recreate this branch from the head of main with just my changes and update the PR.

[ollietreend]

This works on my Intel-based Mac 👍🏻