Switch to AWS' dual-stack S3 URLs (heroku#1717)

The default AWS S3 URLs only support IPv4, whereas the dual-stack
URLs support both IPv4 and IPv6:
https://docs.aws.amazon.com/AmazonS3/latest/API/ipv6-access.html
https://docs.aws.amazon.com/AmazonS3/latest/API/dual-stack-endpoints.html

By switching to the dual-stack URLs, it means systems that support IPv6
will now use it instead of IPv4, which is helpful in IPv6 environments where
IPv4 traffic has to fall back to being routed via NAT gateways (which has
performance and ingress cost implications).

See also:
https://salesforce-internal.slack.com/archives/C01R6FJ738U/p1770827176094169

GUS-W-21341735.

Author: edmorley

CHANGELOG.md

@@ -2,13 +2,13 @@
 
 ## [Unreleased]
 
+- Changed the S3 URLs used for downloads to use AWS' dual-stack (IPv6 compatible) endpoint. ([#1717](https://github.com/heroku/heroku-buildpack-ruby/pull/1717))
 - Fix bug where an invalid DATABASE_URL is set when the adapter is not known (https://github.com/heroku/heroku-buildpack-ruby/pull/1715).
 
 ## [v347] - 2026-02-02
 
 - JRuby 10.0.3.0 is now available
 
-
 ## [v346] - 2026-02-02
 
 - Add metric: Track apps with and without `BUNDLED WITH` in the `Gemfile.lock`

bin/compile

@@ -42,7 +42,7 @@ if detect_needs_java "$BUILD_DIR"; then
 EOM
 
   build_data::kv_string "java_origin" "ruby_buildpack"
-  compile_buildpack_v2 "$BUILD_DIR" "$CACHE_DIR" "$ENV_DIR" "https://buildpack-registry.s3.us-east-1.amazonaws.com/buildpacks/heroku/jvm.tgz" "heroku/jvm"
+  compile_buildpack_v2 "$BUILD_DIR" "$CACHE_DIR" "$ENV_DIR" "https://buildpack-registry.s3.dualstack.us-east-1.amazonaws.com/buildpacks/heroku/jvm.tgz" "heroku/jvm"
 fi
 
 "$bootstrap_ruby_dir"/bin/ruby "$BIN_DIR/support/ruby_compile.rb" "$@"

bin/support/bash_functions.sh

@@ -57,7 +57,7 @@ detect_needs_java()
 #
 # Example:
 #
-#   compile_buildpack_v2 "$build_dir" "$cache_dir" "$env_dir" "https://buildpack-registry.s3.us-east-1.amazonaws.com/buildpacks/heroku/nodejs.tgz" "heroku/nodejs"
+#   compile_buildpack_v2 "$build_dir" "$cache_dir" "$env_dir" "https://buildpack-registry.s3.dualstack.us-east-1.amazonaws.com/buildpacks/heroku/nodejs.tgz" "heroku/nodejs"
 #
 compile_buildpack_v2()
 {

bin/support/download_ruby

@@ -32,9 +32,9 @@ ruby_url() {
   if [ "$stack" == "heroku-24" ]; then
     local arch
     arch=$(dpkg --print-architecture)
-    echo "${BUILDPACK_VENDOR_URL:-https://heroku-buildpack-ruby.s3.us-east-1.amazonaws.com}/$stack/$arch/ruby-$version.tgz"
+    echo "${BUILDPACK_VENDOR_URL:-https://heroku-buildpack-ruby.s3.dualstack.us-east-1.amazonaws.com}/$stack/$arch/ruby-$version.tgz"
   else
-    echo "${BUILDPACK_VENDOR_URL:-https://heroku-buildpack-ruby.s3.us-east-1.amazonaws.com}/$stack/ruby-$version.tgz"
+    echo "${BUILDPACK_VENDOR_URL:-https://heroku-buildpack-ruby.s3.dualstack.us-east-1.amazonaws.com}/$stack/ruby-$version.tgz"
   fi
 }
 

bin/test-compile

@@ -37,7 +37,7 @@ if detect_needs_java "$BUILD_DIR"; then
 
 EOM
 
-  compile_buildpack_v2 "$BUILD_DIR" "$CACHE_DIR" "$ENV_DIR" "https://buildpack-registry.s3.us-east-1.amazonaws.com/buildpacks/heroku/jvm.tgz" "heroku/jvm"
+  compile_buildpack_v2 "$BUILD_DIR" "$CACHE_DIR" "$ENV_DIR" "https://buildpack-registry.s3.dualstack.us-east-1.amazonaws.com/buildpacks/heroku/jvm.tgz" "heroku/jvm"
 fi
 
 "$bootstrap_ruby_dir"/bin/ruby "$BIN_DIR/support/ruby_test-compile.rb" "$@"

lib/language_pack/base.rb

@@ -15,7 +15,7 @@ class LanguagePack::Base
   include LanguagePack::ShellHelpers
   extend LanguagePack::ShellHelpers
 
-  VENDOR_URL = ENV["BUILDPACK_VENDOR_URL"] || "https://heroku-buildpack-ruby.s3.us-east-1.amazonaws.com"
+  VENDOR_URL = ENV["BUILDPACK_VENDOR_URL"] || "https://heroku-buildpack-ruby.s3.dualstack.us-east-1.amazonaws.com"
   ROOT_DIR = File.expand_path("../../..", __FILE__)
   MULTI_ARCH_STACKS = ["heroku-24"]
   KNOWN_ARCHITECTURES = ["amd64", "arm64"]

lib/language_pack/helpers/nodebin.rb

@@ -15,7 +15,7 @@ def self.hardcoded_node_lts(arch:)
   def self.hardcoded_yarn
     {
       "number" => YARN_VERSION,
-      "url" => "https://heroku-nodebin.s3.us-east-1.amazonaws.com/yarn/release/yarn-v#{YARN_VERSION}.tar.gz"
+      "url" => "https://heroku-nodebin.s3.dualstack.us-east-1.amazonaws.com/yarn/release/yarn-v#{YARN_VERSION}.tar.gz"
     }
   end
 

lib/language_pack/ruby.rb

@@ -566,7 +566,7 @@ def install_binaries
 
   # vendors individual binary into the slug
   # @param [String] name of the binary package from S3.
-  #   Example: https://heroku-buildpack-ruby.s3.us-east-1.amazonaws.com/node-0.4.7.tgz, where name is "node-0.4.7"
+  #   Example: https://heroku-buildpack-ruby.s3.dualstack.us-east-1.amazonaws.com/node-0.4.7.tgz, where name is "node-0.4.7"
   def install_binary(name)
     topic "Installing #{name}"
     bin_dir = "bin"