Support checking whether a domain points at a GitHub Pages IP address

[jdennes]

Adds the ability to check whether or not a domain is pointed at a GitHub Pages IP address.

› script/console
+ bundle exec pry -r ./lib/github-pages-health-check
[1] pry(main)> check = GitHubPages::HealthCheck.new("getbootstrap.com")
=> #<GitHubPages::HealthCheck @domain="getbootstrap.com" valid?=true>
[2] pry(main)> check.pointed_to_github_pages_ip?
=> true
[3] pry(main)> check = GitHubPages::HealthCheck.new("example.com")
=> #<GitHubPages::HealthCheck @domain="example.com" valid?=false>
[4] pry(main)> check.pointed_to_github_pages_ip?
=> false

Based on:

› dig getbootstrap.com
;getbootstrap.com.      IN  A
getbootstrap.com.   60  IN  A   192.30.252.153

› dig example.com
;example.com.           IN  A
example.com.        60  IN  A   93.184.216.34

Would be grateful for any feedback/suggestions.

/cc @benbalter @spraints @tekkub

[benbalter]

👍. I could have sworn we exposed pages IPs through the meta API, but I guess not.

[tekkub]

@benbalter nope, but I don't think we want to rely on that here anyway. If we change IPs around again in the future, we'll need to be able to tell people when they have their DNS set for the old IPs (this is why LEGACY_IP_ADDRESSES exists and is hard-coded). I think it makes sense to hard-code the current IPs in as well, if we make a change in the future it will be a very deliberate action. It's not something I think we'd be doing frequently anyway.

[spraints]

👍

[jdennes]

@benbalter Would you like to cut a new release?

[jdennes]

Would you like to cut a new release?

Actually, we should wait for #15.

[spraints]

Would you like to cut a new release?

Actually, we should wait for #15.

#15 is merged, so I think we're ready for a new release?

[benbalter]

@tekkub makes total sense. Thanks for walking through it with me.

Cutting a new release now.

[benbalter]

💥 https://github.com/github/pages-health-check/releases/tag/v0.3.0