feat(config): Add optional Docker extraHosts (part 1)

[MAHDTech]

Overview

This is part 1/2.

This PR adds an additional configuration item to the Docker options called extraHosts

Further detail about it's intended use case is documented in part 2.

Related

Part 2

[peterpeterparker]

There is likely a related test suite, if you could add a snippet to it that would be great as well.

[MAHDTech]

You're definetly right, it is very broad.

There are a few options here according to the docs

1. IPv4 Address my-hostname=8.8.8.8
2. IPv6 Address myhostv6=::1
3. IPv6 address (bracketed) myhostv6=[2001:db8::33]
4. Keywords host.docker.internal=host-gateway

So my best attempts can think of are to use either

• use regex 🤮
• use the tuple method you suggested.

If we go with tuple, it will need to have logic in part 2 to re-assemble it.

I'm not the greatest at regex but something like this could work;

const ExtraHostEntrySchema = z
  .string()
  .regex(
    /^[^=:]+[=:](\d{1,3}(\.\d{1,3}){3}|[0-9a-fA-F:]+|\[[0-9a-fA-F:]+\]|host-gateway)$/,
    'Must be in the format "hostname=ip", "hostname=host-gateway", or "hostname:ip"'
  );

extraHosts: z.array(ExtraHostEntrySchema).optional()

I like the tuple idea it makes it much cleaner on this side, and we get to use those cool zod builtins z.ipv4() and z.ipv6()

const HostNameSchema = z.string().min(1);

const ExtraHostEntrySchema = z.tuple([
  HostNameSchema,
  z.union([z.ipv4(), z.ipv6(), z.literal('host-gateway'), HostNameSchema])
]);

extraHosts: z.array(ExtraHostEntrySchema).optional()

On the CLI side, we would then need to join: ([host, dest]) => ${host}:${dest} before it gets passed in to --add-host

Are you leaning a certain way, regex always feels brittle to me but if done right could work.

[peterpeterparker]

LGTM, thanks a lot!

[peterpeterparker]

I'll maybe add a rule to prevent empty.