feat(support): use gzip to create the buildpack archive

This buildpack can be used in other buildpacks requiring a JVM.
Consequently, we package it and upload it to an Object Storage, from
where it can be downloaded and then executed.

We used to use a .tar.xz archive. This patch switches to a classical .tgz
archive.

Instructions in the README file have been updated to reflect the
changes.

The .tar.xz archive is still available so we don't break existing
buildpacks using this kind of archive.

Author: Frzk

README.md

@@ -44,12 +44,12 @@ behavior and versioning on Scalingo.
 # Determine the root directory of your own (host) buildpack
 HOST_BUILDPACK_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && cd .. && pwd)"
 
-JVM_BUILDPACK_URL="https://buildpacks-repository.s3.eu-central-1.amazonaws.com/jvm-common.tar.xz"
+JVM_BUILDPACK_URL="https://buildpacks-repository.s3.eu-central-1.amazonaws.com/jvm.tgz"
 
 mkdir -p /tmp/jvm-common
 curl --silent --fail --retry 3 --retry-connrefused --connect-timeout 5 \
     --location "${JVM_BUILDPACK_URL}" \
-    | tar --extract --xz --touch --directory=/tmp/jvm-common --strip-components=1
+    | tar --extract --gzip --touch --directory=/tmp/jvm-common --strip-components=1
 
 # Source in a sub-shell to keep your buildpack's environment clean
 ( source /tmp/jvm-common/bin/java \

upload-jvm-common.sh

@@ -19,46 +19,58 @@ set -e
 # set -x
 
 print_usage() {
-  echo "Synopsis:" >&2
-  echo "$0" >&2
+	echo "Synopsis:" >&2
+	echo "$0" >&2
 }
 
 if [[ $# -gt 0 ]]; then
-  print_usage
-  exit 1
+	print_usage
+	exit 1
 fi
 
 cur_dir="$(cd "$(dirname "${0}")" && pwd)"
 cd "${cur_dir}"
 
-archive_name="jvm-common.tar.xz"
+archive_name="jvm"
 
-echo "---> Creating the archive ${archive_name}"
+echo "---> Creating archives"
 
 jvm_common_dir="$(mktemp --tmpdir=/tmp --directory jvm-common-XXXX)"
 ignore_files="$(./tools/stoml ./buildpack.toml publish.Ignore.files)"
 exclude_opts="--exclude=tools"
 
 for f in ${ignore_files}; do
-  exclude_opts="${exclude_opts} --exclude=${f}"
+	exclude_opts="${exclude_opts} --exclude=${f}"
 done
 
 # We use rsync instead of cp to copy files excluding some other files
-rsync --recursive --perms --times --group --owner "${exclude_opts}" ./* "${jvm_common_dir}"
+rsync --recursive --perms --times --group --owner "${exclude_opts}" ./* \
+	"${jvm_common_dir}"
 
 if [[ $? -ne 0 ]]; then
-  echo "Fail to copy the files to the temporary directory (${jvm_common_dir})" >&2
-  exit 1
+	echo "Fail to copy the files to the temporary directory (${jvm_common_dir})" >&2
+	exit 1
 fi
 
-tar --create --xz --file "${archive_name}" --directory "${jvm_common_dir}" .
+# Create legacy .tar.xz archive:
+tar --create --xz --file "${archive_name}-common.tar.xz" \
+	--directory "${jvm_common_dir}" .
 
 if [[ $? -ne 0 ]]; then
-  echo "Error when creating the archive" >&2
-  exit 1
+	echo "Error when creating the .tar.xz archive" >&2
+	exit 1
 fi
+echo "  .tar.xz: OK."
 
-echo "---> Archive created"
+# Create .tgz archive:
+tar --create --gzip --file "${archive_name}.tgz" \
+	--directory "${jvm_common_dir}" .
+
+if [[ $? -ne 0 ]]; then
+	echo "Error when creating the .tgz archive" >&2
+	exit 1
+fi
+echo "  .tgz: OK."
 
 which s3cmd >/dev/null ||
   echo "s3cmd is not available in your PATH" >&2 ||
@@ -67,20 +79,36 @@ which s3cmd >/dev/null ||
 
 s3_bucket="buildpacks-repository"
 
-echo "---> Uploading ${archive_name} to S3 (${s3_bucket})"
+echo "---> Uploading archives to S3 (${s3_bucket})"
 
 s3cmd \
 	--access_key="${AWS_ACCESS_KEY_ID}" \
 	--secret_key="${AWS_SECRET_ACCESS_KEY}" \
 	--access_token="${AWS_SESSION_TOKEN}" \
 	--acl-public --quiet \
-	put "${archive_name}" \
+	put "${archive_name}-common.tar.xz" \
 	"s3://${s3_bucket}/"
 
 if [[ $? -ne 0 ]]; then
-  echo "Error uploading the archive to S3" >&2
-  exit 1
+	echo "Error uploading the .tar.xz archive to S3" >&2
+	exit 1
+fi
+echo "  .tar.xz: OK."
+
+s3cmd \
+	--access_key="${AWS_ACCESS_KEY_ID}" \
+	--secret_key="${AWS_SECRET_ACCESS_KEY}" \
+	--access_token="${AWS_SESSION_TOKEN}" \
+	--acl-public --quiet \
+	put "${archive_name}.tgz" \
+	"s3://${s3_bucket}/"
+
+if [[ $? -ne 0 ]]; then
+	echo "Error uploading the .tgz archive to S3" >&2
+	exit 1
 fi
+echo "  .tgz: OK."
+
 
 echo "---> Deleting the temporary files"
-rm -r "${jvm_common_dir}" "${archive_name}"
+rm -r "${jvm_common_dir}" "${archive_name}-common.tar.xz" "${archive_name}.tgz"