cmd/vendor-install.sh: allow download vendors from HOMEBREW_ARTIFACT_DOMAIN and HOMEBREW_BOTTLE_DOMAIN

[XuehaiPan]

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PR #11070 drops the support for users to download portable-ruby from HOMEBREW_BOTTLE_DOMAIN. Users cannot use geolocalized mirrors to speed up downloading and only packages host on GitHub are supported. (Ref tuna/issues#1224 (comment) and tuna/mirror-web#292 (comment))

This PR takes the URL from HOMEBREW_BOTTLE_DOMAIN back and adds the URL from HOMEBREW_ARTIFACT_DOMAIN (as documented for this environment variable).

This implementation may be a bit tricky to use the eval statement to expand an array from the name.

# Expand the name to an array of variables
# The array name must be "${VENDOR_NAME}_URLs"! Otherwise substitution errors will occur!
read -r -a VENDOR_URLs <<< "$(eval "echo "\$\{${VENDOR_NAME}_URLs[@]\}"")"

---

Some tests:

• Unset HOMEBREW_ARTIFACT_DOMAIN and HOMEBREW_BOTTLE_DOMAIN:

$ brew cleanup -s --prune 0
Removing: /home/PanXuehai/.cache/Homebrew/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz... (10.4MB)

$ unset HOMEBREW_{ARTIFACT,BOTTLE}_DOMAIN

$ brew vendor-install ruby 
==> Downloading https://ghcr.io/v2/homebrew/portable-ruby/portable-ruby/blobs/sha256:97e639a64dcec285392b53ad804b5334c324f1d2a8bdc2b5087b8bf8051e332f
################################################################################ 100.0%
==> Pouring portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz

• Invalid HOMEBREW_ARTIFACT_DOMAIN and HOMEBREW_BOTTLE_DOMAIN:

$ brew cleanup -s --prune 0
Removing: /home/PanXuehai/.cache/Homebrew/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz... (10.4MB)

$ export HOMEBREW_ARTIFACT_DOMAIN="https://localhost:10000"  # a invalid URL
$ export HOMEBREW_BOTTLE_DOMAIN="https://localhost:20000"  # a invalid URL

$ brew vendor-install ruby 
==> Downloading https://localhost:10000/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
curl: (35) OpenSSL SSL_connect: Connection reset by peer in connection to localhost:10000

==> Downloading https://localhost:20000/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
curl: (35) OpenSSL SSL_connect: Connection reset by peer in connection to localhost:20000

==> Downloading https://ghcr.io/v2/homebrew/portable-ruby/portable-ruby/blobs/sha256:97e639a64dcec285392b53ad804b5334c324f1d2a8bdc2b5087b8bf8051e332f
################################################################################ 100.0%
==> Pouring portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz

• Valid HOMEBREW_BOTTLE_DOMAIN:

$ brew cleanup -s --prune 0
Removing: /home/PanXuehai/.cache/Homebrew/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz... (10.4MB)

$ export HOMEBREW_ARTIFACT_DOMAIN="https://localhost:10000"  # a invalid URL
$ export HOMEBREW_BOTTLE_DOMAIN="https://mirrors.tuna.tsinghua.edu.cn/linuxbrew-bottles"

$ brew vendor-install ruby 
==> Downloading https://localhost:10000/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
curl: (35) OpenSSL SSL_connect: Connection reset by peer in connection to localhost:10000

==> Downloading https://mirrors.tuna.tsinghua.edu.cn/linuxbrew-bottles/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
################################################################################ 100.0%
==> Pouring portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz

$ brew vendor-install ruby
==> Downloading https://localhost:10000/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
Already downloaded: /home/PanXuehai/.cache/Homebrew/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
==> Pouring portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz

$ unset HOMEBREW_ARTIFACT_DOMAIN

$ brew vendor-install ruby
==> Downloading https://mirrors.tuna.tsinghua.edu.cn/linuxbrew-bottles/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
Already downloaded: /home/PanXuehai/.cache/Homebrew/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
==> Pouring portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz

$ brew cleanup -s --prune 0
Removing: /home/PanXuehai/.cache/Homebrew/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz... (10.4MB)

$ brew vendor-install ruby 
==> Downloading https://mirrors.tuna.tsinghua.edu.cn/linuxbrew-bottles/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
################################################################################ 100.0%
==> Pouring portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz

• All fails:

$ brew cleanup -s --prune 0
Removing: /home/PanXuehai/.cache/Homebrew/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz... (10.4MB)

$ export HOMEBREW_ARTIFACT_DOMAIN="https://localhost:10000"  # a invalid URL
$ export HOMEBREW_BOTTLE_DOMAIN="https://mirrors.tuna.tsinghua.edu.cn/linuxbrew-bottles"

$ export http_proxy="http://localhost:20000"  # a invalid Proxy
$ export https_proxy="http://localhost:20000"  # a invalid Proxy

$ brew vendor-install ruby 
==> Downloading https://localhost:10000/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
curl: (7) Failed to connect to localhost port 20000: Connection refused

==> Downloading https://mirrors.tuna.tsinghua.edu.cn/linuxbrew-bottles/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
curl: (7) Failed to connect to localhost port 20000: Connection refused

==> Downloading https://ghcr.io/v2/homebrew/portable-ruby/portable-ruby/blobs/sha256:97e639a64dcec285392b53ad804b5334c324f1d2a8bdc2b5087b8bf8051e332f
curl: (7) Failed to connect to localhost port 20000: Connection refused

==> Downloading https://github.com/Homebrew/homebrew-portable-ruby/releases/download/2.6.3_2/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
curl: (7) Failed to connect to localhost port 20000: Connection refused

Error: Failed to download ruby from the following locations:
  - https://localhost:10000/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
  - https://mirrors.tuna.tsinghua.edu.cn/linuxbrew-bottles/bottles-portable-ruby/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz
  - https://ghcr.io/v2/homebrew/portable-ruby/portable-ruby/blobs/sha256:97e639a64dcec285392b53ad804b5334c324f1d2a8bdc2b5087b8bf8051e332f
  - https://github.com/Homebrew/homebrew-portable-ruby/releases/download/2.6.3_2/portable-ruby-2.6.3_2.x86_64_linux.bottle.tar.gz

Do not file an issue on GitHub about this; you will need to figure out for
yourself what issue with your internet connection restricts your access to
GitHub (used for Homebrew updates and binary packages).

[MikeMcQuaid]

Thanks again @XuehaiPan!