Use jvm buildpack to install JRuby dependencies (#1119)

* Use jvm buildpack to install JRuby dependencies

Currently, the jvm logic is duplicated in this buildpack and the jvm buildpack. By using the JVM buildpack we can reduce duplication and increase consistency across the Heroku platform.

* Use named variables instead of bash args

Previously the function compile_buildpack_v2 directly uses $1, $2, and $3. This change updates this function to instead use named local variables.

In addition, there was a typo in the output to the user.

CHANGELOG.md

@@ -1,5 +1,7 @@
 # Main (unreleased)
 
+* Ruby buildpack now relies on the JVM buildpack to install java for Jruby apps (https://github.com/heroku/heroku-buildpack-ruby/pull/1119)
+
 ## v223 (1/22/2021)
 
 * Fix Gemfile.lock read bug from preventing propper removal of BUNDLED WITH declaration (https://github.com/heroku/heroku-buildpack-ruby/pull/1108)

bin/compile

@@ -2,10 +2,30 @@
 # The actual compilation code lives in `bin/support/ruby_compile`. This file instead
 # bootstraps the ruby needed and then executes `bin/support/ruby_compile`
 
+BUILD_DIR=$1
+CACHE_DIR=$2
+ENV_DIR=$3
 BIN_DIR=$(cd $(dirname $0); pwd)
 BUILDPACK_DIR=$(dirname $BIN_DIR)
 
 source "$BIN_DIR/support/bash_functions.sh"
 heroku_buildpack_ruby_install_ruby "$BIN_DIR" "$BUILDPACK_DIR"
 
+if detect_needs_java "$BUILD_DIR"; then
+  cat <<EOM
+
+       ## Warning: Your app needs java
+
+       The Ruby buildpack determined your app needs java installed
+       we recommend you add the jvm buildpack to your application:
+
+         $ heroku buildpacks:add heroku/jvm --index=1
+
+-----> Installing Java
+
+EOM
+
+  compile_buildpack_v2 "$BUILD_DIR" "$CACHE_DIR" "$ENV_DIR" "https://buildpack-registry.s3.amazonaws.com/buildpacks/heroku/jvm.tgz" "heroku/jvm"
+fi
+
 $heroku_buildpack_ruby_dir/bin/ruby $BIN_DIR/support/ruby_compile $@

bin/support/bash_functions.sh

@@ -1,3 +1,15 @@
+#!/usr/bin/env bash
+
+curl_retry_on_18() {
+  local ec=18;
+  local attempts=0;
+  while (( ec == 18 && attempts++ < 3 )); do
+    curl "$@" # -C - would return code 33 if unsupported by server
+    ec=$?
+  done
+  return $ec
+}
+
 # This function will install a version of Ruby onto the
 # system for the buidlpack to use. It coordinates download
 # and setting appropriate env vars for execution
@@ -44,3 +56,100 @@ heroku_buildpack_ruby_install_ruby()
   export PATH=$heroku_buildpack_ruby_dir/bin/:$PATH
   unset GEM_PATH
 }
+
+which_java()
+{
+  which java > /dev/null
+}
+
+# Detects if a given Gemfile.lock has jruby in it
+# $ cat Gemfile.lock | grep jruby # => ruby 2.5.7p001 (jruby 9.2.13.0)
+detect_needs_java()
+{
+  local app_dir=$1
+  local gemfile_lock="$app_dir/Gemfile.lock"
+  # local needs_jruby=0
+  local skip_java_install=1
+
+  if which_java; then
+    return $skip_java_install
+  fi
+  grep "(jruby " "$gemfile_lock" --quiet
+}
+
+# Runs another buildpack against the build dir
+#
+# Example:
+#
+#   compile_buildpack_v2 "$build_dir" "$cache_dir" "$env_dir" "https://buildpack-registry.s3.amazonaws.com/buildpacks/heroku/nodejs.tgz" "heroku/nodejs"
+#
+compile_buildpack_v2()
+{
+  local build_dir=$1
+  local cache_dir=$2
+  local env_dir=$3
+  local buildpack=$4
+  local name=$5
+
+  local dir
+  local url
+  local branch
+
+  dir=$(mktemp -t buildpackXXXXX)
+  rm -rf "$dir"
+
+  url=${buildpack%#*}
+  branch=${buildpack#*#}
+
+  if [ "$branch" == "$url" ]; then
+    branch=""
+  fi
+
+  if [ "$url" != "" ]; then
+    echo "-----> Downloading Buildpack: ${name}"
+
+    if [[ "$url" =~ \.tgz$ ]] || [[ "$url" =~ \.tgz\? ]]; then
+      mkdir -p "$dir"
+      curl_retry_on_18 -s "$url" | tar xvz -C "$dir" >/dev/null 2>&1
+    else
+      git clone "$url" "$dir" >/dev/null 2>&1
+    fi
+    cd "$dir" || return
+
+    if [ "$branch" != "" ]; then
+      git checkout "$branch" >/dev/null 2>&1
+    fi
+
+    # we'll get errors later if these are needed and don't exist
+    chmod -f +x "$dir/bin/{detect,compile,release}" || true
+
+    framework=$("$dir"/bin/detect "$build_dir")
+
+    # shellcheck disable=SC2181
+    if [ $? == 0 ]; then
+      echo "-----> Detected Framework: $framework"
+      "$dir"/bin/compile "$build_dir" "$cache_dir" "$env_dir"
+
+      # shellcheck disable=SC2181
+      if [ $? != 0 ]; then
+        exit 1
+      fi
+
+      # check if the buildpack left behind an environment for subsequent ones
+      if [ -e "$dir/export" ]; then
+        set +u # http://redsymbol.net/articles/unofficial-bash-strict-mode/#sourcing-nonconforming-document
+        # shellcheck disable=SC1090
+        source "$dir/export"
+        set -u # http://redsymbol.net/articles/unofficial-bash-strict-mode/#sourcing-nonconforming-document
+      fi
+
+      if [ -x "$dir/bin/release" ]; then
+        "$dir"/bin/release "$build_dir" > "$1"/last_pack_release.out
+      fi
+    else
+      echo "Couldn't detect any framework for this buildpack. Exiting."
+      exit 1
+    fi
+  fi
+}
+

bin/test-compile

@@ -2,10 +2,30 @@
 # The actual `bin/test-compile` code lives in `bin/ruby_test-compile`. This file instead
 # bootstraps the ruby needed and then executes `bin/ruby_test-compile`
 
+BUILD_DIR=$1
+CACHE_DIR=$2
+ENV_DIR=$3
 BIN_DIR=$(cd $(dirname $0); pwd)
 BUILDPACK_DIR=$(dirname $BIN_DIR)
 
 source "$BIN_DIR/support/bash_functions.sh"
 heroku_buildpack_ruby_install_ruby "$BIN_DIR" "$BUILDPACK_DIR"
 
+if detect_needs_java "$BUILD_DIR"; then
+  cat <<EOM
+
+       ## Warning: Your app needs java
+
+       The Ruby buildpack determined your app needs java installed
+       we recommend you add the jvm buildpack to your application:
+
+         $ heroku buildpacks:add heroku/jvm --index=1
+
+-----> Installing Java
+
+EOM
+
+  compile_buildpack_v2 "$BUILD_DIR" "$CACHE_DIR" "$ENV_DIR" "https://buildpack-registry.s3.amazonaws.com/buildpacks/heroku/jvm.tgz" "heroku/jvm"
+fi
+
 $heroku_buildpack_ruby_dir/bin/ruby $BIN_DIR/support/ruby_test-compile $@

changelogs/unreleased/jvm_installer_default.md

@@ -0,0 +1,13 @@
+## JVM support for JRuby apps is now provided by the `heroku/jvm` buildpack
+
+JRuby applications require the JVM to run. Before this change, the JVM for JRuby apps was provided by the `heroku/ruby` buildpack for JRuby applications.
+
+Now the custom JVM installation logic in the `heroku/ruby` buildpack has been removed, and instead, the `heroku/jvm` buildpack will be called directly by the Ruby buildpack.
+
+Instead of relying on this functionality, it is recommended to manually require the `heroku/jvm` buildpack for your application:
+
+```
+$ heroku buildpacks:add heroku/jvm --index=1
+```
+
+For more information on JRuby support, see the [Heroku Ruby Support page](https://devcenter.heroku.com/articles/ruby-support).

hatchet.json

@@ -22,7 +22,6 @@
     "sharpstone/cd_ruby",
     "sharpstone/ruby_193_jruby_173",
     "sharpstone/ruby_193_jruby_176",
-    "sharpstone/ruby_193_jruby_1_7_27",
     "sharpstone/ruby_193_jruby_17161_jdk7",
     "sharpstone/ruby_193_bad_patch_cedar_14",
     "sharpstone/ruby_25",

hatchet.lock

@@ -95,8 +95,6 @@
   - a08e8b2cc61d08bd611accaa455dbcbfff80f831
 - - "./repos/ruby/ruby_193_jruby_176"
   - 9fcbc184cb386abc8784e9935d52d403e35c532c
-- - "./repos/ruby/ruby_193_jruby_1_7_27"
-  - 06d5e86180ff0e5b6894f823736cd649dcfebed4
 - - "./repos/ruby/ruby_25"
   - 0cb3df80d55b61e9417f2ac00adb06e15ae37982
 - - "./repos/ruby/ruby_version_does_not_exist"