improve portability of reproducible tarballs by replacing external tar command with tarfile module from Python standard library

easybuild/framework/easyblock.py

@@ -49,6 +49,7 @@
 import os
 import re
 import stat
+import sys
 import tempfile
 import time
 import traceback
@@ -358,34 +359,49 @@ def get_checksum_for(self, checksums, filename=None, index=None):
         :param filename: name of the file to obtain checksum for
         :param index: index of file in list
         """
-        checksum = None
-
-        # sometimes, filename are specified as a dict
+        chksum_input = filename
+        chksum_input_git = None
+        # if filename is provided as dict, take 'filename' key
         if isinstance(filename, dict):
-            filename = filename['filename']
+            chksum_input = filename['filename']
+            chksum_input_git = filename.get('git_config', None)
+        # early return if no filename given
+        if chksum_input is None:
+            self.log.debug("Cannot get checksum without a file name")
+            return None
+
+        if sys.version_info[0] >= 3 and sys.version_info[1] < 9:
+            # ignore any checksum for given filename due to changes in python/cpython#90021
+            # checksums of tarballs made by EB of git repos cannot be reliably checked prior to Python 3.9
+            if chksum_input_git is not None:
+                self.log.deprecated(
+                    "Reproducible tarballs of git repos are only supported in Python 3.9+. "
+                    f"Checksum of {chksum_input} cannot be verified.",
+                    '6.0'
+                )
+                return None
 
+        checksum = None
         # if checksums are provided as a dict, lookup by source filename as key
         if isinstance(checksums, dict):
-            if filename is not None and filename in checksums:
-                checksum = checksums[filename]
-            else:
-                checksum = None
-        elif isinstance(checksums, (list, tuple)):
-            if index is not None and index < len(checksums) and (index >= 0 or abs(index) <= len(checksums)):
+            try:
+                checksum = checksums[chksum_input]
+            except KeyError:
+                self.log.debug("Checksum not found for file: %s", chksum_input)
+        elif isinstance(checksums, (list, tuple)) and index is not None:
+            try:
                 checksum = checksums[index]
-            else:
-                checksum = None
-        elif checksums is None:
-            checksum = None
-        else:
+            except IndexError:
+                self.log.debug("Checksum not found for index list: %s", index)
+        elif checksums is not None:
             raise EasyBuildError("Invalid type for checksums (%s), should be dict, list, tuple or None.",
                                  type(checksums))
 
         if checksum is None or build_option("checksum_priority") == CHECKSUM_PRIORITY_JSON:
             json_checksums = self.get_checksums_from_json()
-            return json_checksums.get(filename, None)
-        else:
-            return checksum
+            return json_checksums.get(chksum_input, None)
+
+        return checksum
 
     def get_checksums_from_json(self, always_read=False):
         """

easybuild/tools/filetools.py

@@ -48,13 +48,15 @@
 import inspect
 import itertools
 import os
+import pathlib
 import platform
 import re
 import shutil
 import signal
 import stat
 import ssl
 import sys
+import tarfile
 import tempfile
 import time
 import zlib
@@ -1402,18 +1404,20 @@ def get_local_dirs_purged():
     return new_dir
 
 
-def find_extension(filename):
+def find_extension(filename, required=True):
     """Find best match for filename extension."""
     # sort by length, so longest file extensions get preference
     suffixes = sorted(EXTRACT_CMDS.keys(), key=len, reverse=True)
     pat = r'(?P<ext>%s)$' % '|'.join([s.replace('.', '\\.') for s in suffixes])
     res = re.search(pat, filename, flags=re.IGNORECASE)
+
     if res:
-        ext = res.group('ext')
-    else:
+        return res.group('ext')
+
+    if required:
         raise EasyBuildError("%s has unknown file extension", filename)
 
-    return ext
+    return None
 
 
 def extract_cmd(filepath, overwrite=False):
@@ -2644,7 +2648,7 @@ def get_source_tarball_from_git(filename, target_dir, git_config):
     """
     Downloads a git repository, at a specific tag or commit, recursively or not, and make an archive with it
 
-    :param filename: name of the archive to save the code to (must be .tar.gz)
+    :param filename: name of the archive to save the code to (must be extensionless)
     :param target_dir: target directory where to save the archive to
     :param git_config: dictionary containing url, repo_name, recursive, and one of tag or commit
     """
@@ -2680,8 +2684,10 @@ def get_source_tarball_from_git(filename, target_dir, git_config):
     if not url:
         raise EasyBuildError("url not specified in git_config parameter")
 
-    if not filename.endswith('.tar.gz'):
-        raise EasyBuildError("git_config currently only supports filename ending in .tar.gz")
+    file_ext = find_extension(filename, required=False)
+    if file_ext:
+        print_warning(f"Ignoring extension of filename '{filename}' set in git_config parameter")
+        filename = filename[:-len(file_ext)]
 
     # prepare target directory and clone repository
     mkdir(target_dir, parents=True)
@@ -2768,37 +2774,82 @@ def get_source_tarball_from_git(filename, target_dir, git_config):
                 run_shell_cmd(cmd, work_dir=work_dir, hidden=True, verbose_dry_run=True)
 
     # Create archive
-    archive_path = os.path.join(target_dir, filename)
-
-    if keep_git_dir:
-        # create archive of git repo including .git directory
-        tar_cmd = ['tar', 'cfvz', archive_path, repo_name]
-    else:
-        # create reproducible archive
-        # see https://reproducible-builds.org/docs/archives/
-        tar_cmd = [
-            # print names of all files and folders excluding .git directory
-            'find', repo_name, '-name ".git"', '-prune', '-o', '-print0',
-            # reset access and modification timestamps to epoch 0 (equivalent to --mtime in GNU tar)
-            '-exec', 'touch', '--date=@0', '{}', r'\;',
-            # reset file permissions of cloned repo (equivalent to --mode in GNU tar)
-            '-exec', 'chmod', '"go+u,go-w"', '{}', r'\;', '|',
-            # sort file list (equivalent to --sort in GNU tar)
-            'LC_ALL=C', 'sort', '--zero-terminated', '|',
-            # create tarball in GNU format with ownership and permissions reset
-            'tar', '--create', '--no-recursion', '--owner=0', '--group=0', '--numeric-owner',
-            '--format=gnu', '--null', '--files-from', '-', '|',
-            # compress tarball with gzip without original file name and timestamp
-            'gzip', '--no-name', '>', archive_path
-        ]
-    run_shell_cmd(' '.join(tar_cmd), work_dir=tmpdir, hidden=True, verbose_dry_run=True)
+    repo_path = os.path.join(tmpdir, repo_name)
+    reproducible = not keep_git_dir  # presence of .git directory renders repo unreproducible
+    archive_path = make_archive(repo_path, archive_name=filename, archive_dir=target_dir, reproducible=reproducible)
 
     # cleanup (repo_name dir does not exist in dry run mode)
     remove(tmpdir)
 
     return archive_path
 
 
+def make_archive(dir_path, archive_name=None, archive_dir=None, reproducible=False):
+    """
+    Create a compressed tar archive in XZ format.
+
+    :dir_path: string with path to directory to be archived
+    :archive_name: string with extensionless filename of archive
+    :archive_dir: string with path to directory to place the archive
+    :reproducuble: make a tarball that is reproducible accross systems
+    see https://reproducible-builds.org/docs/archives/
+
+    Archive is compressed with LZMA into a .xz because that is compatible with
+    a reproducible archive. Other formats like .gz are not reproducible due to
+    arbitrary strings and timestamps getting added into their metadata.
+    """
+    def reproducible_filter(tarinfo):
+        "Filter out system-dependent data from tarball"
+        # contents of '.git' subdir are inherently system dependent
+        if "/.git/" in tarinfo.name or tarinfo.name.endswith("/.git"):
+            return None
+        # set timestamp to epoch 0
+        tarinfo.mtime = 0
+        # reset file permissions by applying go+u,go-w
+        user_mode = tarinfo.mode & stat.S_IRWXU
+        group_mode = (user_mode >> 3) & ~stat.S_IWGRP  # user mode without write
+        other_mode = group_mode >> 3  # user mode without write
+        tarinfo.mode = (tarinfo.mode & ~0o77) | group_mode | other_mode
+        # reset ownership numeric UID/GID 0
+        tarinfo.uid = tarinfo.gid = 0
+        tarinfo.uname = tarinfo.gname = ""
+        return tarinfo
+
+    if archive_name is None:
+        archive_name = os.path.basename(dir_path)
+
+    archive_ext = ".tar.xz"
+    archive_filename = archive_name + archive_ext
+    archive_path = archive_filename if archive_dir is None else os.path.join(archive_dir, archive_filename)
+
+    if build_option('extended_dry_run'):
+        # early return in dry run mode
+        dry_run_msg("Archiving '%s' into '%s'...", dir_path, archive_path)
+        return archive_path
+
+    # TODO: replace with TarFile.add(recursive=True) when support for Python 3.6 drops
+    # since Python v3.7 tarfile automatically orders the list of files added to the archive
+    dir_files = [dir_path]
+    # pathlib's glob includes hidden files
+    dir_files.extend([str(filepath) for filepath in pathlib.Path(dir_path).glob("**/*")])
+    dir_files.sort()  # independent of locale
+
+    dir_path_prefix = os.path.dirname(dir_path)
+    archive_filter = reproducible_filter if reproducible else None
+
+    _log.info("Archiving '%s' into '%s'...", dir_path, archive_path)
+    with tarfile.open(archive_path, "w:xz", format=tarfile.GNU_FORMAT, encoding="utf-8", preset=6) as archive:
+        for filepath in dir_files:
+            # archive with target directory in its top level, remove any prefix in path
+            file_name = os.path.relpath(filepath, start=dir_path_prefix)
+            archive.add(filepath, arcname=file_name, recursive=False, filter=archive_filter)
+            _log.debug("File/folder added to archive '%s': %s", archive_filename, filepath)
+
+    _log.info("Archive '%s' created successfully", archive_filename)
+
+    return archive_path
+
+
 def move_file(path, target_path, force_in_dry_run=False):
     """
     Move a file from path to target_path

test/framework/easyblock.py

@@ -35,6 +35,7 @@
 import sys
 import tempfile
 from inspect import cleandoc
+from test.framework.github import requires_github_access
 from test.framework.utilities import EnhancedTestCase, TestLoaderFiltered, init_config
 from unittest import TextTestRunner
 
@@ -1618,6 +1619,40 @@ def test_fetch_sources(self):
         error_pattern = "Found one or more unexpected keys in 'sources' specification: {'nosuchkey': 'foobar'}"
         self.assertErrorRegex(EasyBuildError, error_pattern, eb.fetch_sources, sources, checksums=[])
 
+    @requires_github_access()
+    def test_fetch_sources_git(self):
+        """Test fetch_sources method from git repo."""
+        testdir = os.path.abspath(os.path.dirname(__file__))
+        ec = process_easyconfig(os.path.join(testdir, 'easyconfigs', 'test_ecs', 't', 'toy', 'toy-0.0.eb'))[0]
+        eb = get_easyblock_instance(ec)
+        eb.src = []
+        sources = [
+            {
+                'filename': 'testrepository.tar.xz',
+                'git_config': {
+                    'repo_name': 'testrepository',
+                    'url': 'https://github.com/easybuilders',
+                    'tag': 'branch_tag_for_test',
+                }
+            }
+        ]
+        checksums = ["00000000"]
+        with self.mocked_stdout_stderr():
+            eb.fetch_sources(sources, checksums=checksums)
+
+        self.assertEqual(len(eb.src), 1)
+        self.assertEqual(eb.src[0]['name'], "testrepository.tar.xz")
+        self.assertExists(eb.src[0]['path'])
+        self.assertEqual(eb.src[0]['cmd'], None)
+
+        reference_checksum = "00000000"
+        if sys.version_info[0] >= 3 and sys.version_info[1] < 9:
+            # checksums of tarballs made by EB cannot be reliably checked prior to Python 3.9
+            # due to changes introduced in python/cpython#90021
+            reference_checksum = None
+
+        self.assertEqual(eb.src[0]['checksum'], reference_checksum)
+
     def test_download_instructions(self):
         """Test use of download_instructions easyconfig parameter."""