Ini adalah usaha saya untuk mencoba membuat tarball deterministik dari repo SVN.
Membutuhkan GNU tar 1.27 atau lebih baru.
Fitur:
- Tarbal deterministik
- Timestamp presisi dalam mikrodetik dari SVN, berkat
paxheader yang diperpanjang
- ID revisi disimpan dalam komentar arsip seperti yang
git archiveakan dilakukan
- Saya menunjukkan keduanya
.tar.gzdan .tar.xzkompresi. Untuk gzip, Anda dapat mengoptimalkan kompresi lebih lanjut dengan menggunakan advdefdari AdvanceCOMP ( advdefmenggunakan perpustakaan zopfli).
Sebagai contoh, saya menggunakan repo subversi sendiri sebagai sumber untuk checkout dan pembuatan tarball. Perhatikan bahwa ini bukan cara SVN mengemas tarbal mereka dan saya tidak terkait dengan pengembangan SVN. Lagipula itu hanya contoh .
# URL of repository to export
url="https://svn.apache.org/repos/asf/subversion/tags/1.9.7/"
# Name of distribution sub-directory
dist_name=subversion-1.9.7-test
# ---------------------------------------------------------------------
info=$(svn info --xml "$url" | tr -- '\t\n' ' ')
revision=$(echo "$info" |
sed 's|.*<commit[^>]* revision="\{0,1\}\([^">]*\)"\{0,1\}>.*|\1|')
tar_name=${dist_name}-r${revision}
# Subversion's commit timestamps can be as precise as 0.000001 seconds,
# but sub-second precision is only available through --xml output
# format.
date=$(echo "$info" |
sed 's|.*<commit[^>]*>.*<date>\([^<]*\)</date>.*</commit>.*|\1|')
# Factors that would make tarball non-deterministic include:
# - umask
# - Ordering of file names
# - Timestamps of directories ("svn export" doesn't update them)
# - User and group names and IDs
# - Format of tar (gnu, ustar or pax)
# - For pax format, the name and contents of extended header blocks
umask u=rwx,go=rx
svn export -r "$revision" "$url" "$dist_name"
# "svn export" will update file modification time to latest time of
# commit that modifies the file, but won't do so on directories.
find . -type d | xargs touch -c -m -d "$date" --
trap 's=$?; rm -f "${tar_name}.tar" || : ; exit $s' 1 2 3 15
# pax extended header allows sub-second precision on modification time.
# The default extended header name pattern ("%d/PaxHeaders.%p/%f")
# would contain a process ID that makes tarball non-deterministic.
# "git archive" would store a commit ID in pax global header (named
# "pax_global_header"). We can do similar.
# GNU tar (<=1.30) has a bug that it rejects globexthdr.mtime that
# contains fraction of seconds.
pax_options=$(printf '%s%s%s%s%s%s' \
"globexthdr.name=pax_global_header," \
"globexthdr.mtime={$(echo ${date}|sed -e 's/\.[0-9]*Z/Z/g')}," \
"comment=${revision}," \
"exthdr.name=%d/PaxHeaders/%f," \
"delete=atime," \
"delete=ctime")
find "$dist_name" \
\( -type d -exec printf '%s/\n' '{}' \; \) -o -print |
LC_ALL=C sort |
tar -c --no-recursion --format=pax --owner=root:0 --group=root:0 \
--pax-option="$pax_options" -f "${tar_name}.tar" -T -
# Compression (gzip/xz) can add additional non-deterministic factors.
# xz format does not store file name or timestamp...
trap 's=$?; rm -f "${tar_name}.tar.xz" || : ; exit $s' 1 2 3 15
xz -9e -k "${tar_name}.tar"
# ...but for gzip, you need either --no-name option or feed the input
# from stdin. This example uses former, and also tries advdef to
# optimize compression if available.
trap 's=$?; rm -f "${tar_name}.tar.gz" || : ; exit $s' 1 2 3 15
gzip --no-name -9 -k "${tar_name}.tar" &&
{ advdef -4 -z "${tar_name}.tar.gz" || : ; }