Re: [PATCH v5 6/7] git-p4: add support for large file systems
On 16 Sep 2015, at 10:36, Luke Diamand <luke@diamand.org> wrote:
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> On 14/09/15 14:26, larsxschneider@gmail.com wrote:
>> From: Lars Schneider <larsxschneider@gmail.com>
>>
>> Perforce repositories can contain large (binary) files. Migrating these
>> repositories to Git generates very large local clones. External storage
>> systems such as Git LFS [1], Git Fat [2], Git Media [3], git-annex [4]
>> try to address this problem.
>>
>> Add a generic mechanism to detect large files based on extension,
>> uncompressed size, and/or compressed size.
>
> Looks excellent! I've got a small few comments (below) and I need to come back and have another look through if that's OK.
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>
> Thanks!
> Luke
>
>>
>> [1] https://git-lfs.github.com/
>> [2] https://github.com/jedbrown/git-fat
>> [3] https://github.com/alebedev/git-media
>> [4] https://git-annex.branchable.com/
>>
>> Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
>> ---
>> Documentation/git-p4.txt | 32 +++++++++++
>> git-p4.py | 139 +++++++++++++++++++++++++++++++++++++++++----
>> t/t9823-git-p4-mock-lfs.sh | 96 +++++++++++++++++++++++++++++++
>> 3 files changed, 257 insertions(+), 10 deletions(-)
>> create mode 100755 t/t9823-git-p4-mock-lfs.sh
>>
>> diff --git a/Documentation/git-p4.txt b/Documentation/git-p4.txt
>> index 82aa5d6..3f21e95 100644
>> --- a/Documentation/git-p4.txt
>> +++ b/Documentation/git-p4.txt
>> @@ -510,6 +510,38 @@ git-p4.useClientSpec::
>> option '--use-client-spec'. See the "CLIENT SPEC" section above.
>> This variable is a boolean, not the name of a p4 client.
>>
>> +git-p4.largeFileSystem::
>> + Specify the system that is used for large (binary) files. Please note
>> + that large file systems do not support the 'git p4 submit' command.
>
> Why is that? Is it just that you haven't implemented support, or is it fundamentally impossible?
If we detect LFS files only by file extension then we could make it work. But then we must not use any git-p4 settings. We would need to rely only on the “.gitattributes” file that is stored in the P4 repository. My implementation also looks at the file size and decides on a individual file basis if a file is stored in LFS. That means all clients need the same file size threshold.
Junio explained the problem in the v4 thread:
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> How is collaboration between those who talk to the same p4 depot
> backed by GitHub LFS expected to work? You use config to set size
> limits and list of file extensions in your repository, and grab new
> changes from p4 and turn them into Git commits (with pointers to LFS
> and the .gitattributes file that records your choice of the config).
> I as a new member to the same project come, clone the resulting Git
> repository from you and then what do I do before talking to the same
> p4 depot to further update the Git history? Are the values recorded
> in .gitattributes (which essentially were derived from your
> configuration) somehow reflected back automatically to my config so
> that our world view would become consistent? Perhaps you added
> 'iso' to largeFileExtensions before I cloned from you, and that
> would be present in the copy of .gitattributes I obtained from you.
> I may be trying to add a new ".iso" file, and I presume that an
> existing .gitattributes entry you created based on the file
> extension automatically covers it from the LFS side, but does my
> "git p4 submit" also know what to do, or would it be broken until I
> add a set of configrations that matches yours?
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>
>> + Only Git LFS [1] is implemented right now. Download
>> + and install the Git LFS command line extension to use this option
>> + and configure it like this:
>> ++
>> +-------------
>> +git config git-p4.largeFileSystem GitLFS
>> +-------------
>> ++
>> + [1] https://git-lfs.github.com/
>> +
>> +git-p4.largeFileExtensions::
>> + All files matching a file extension in the list will be processed
>> + by the large file system. Do not prefix the extensions with '.'.
>> +
>> +git-p4.largeFileThreshold::
>> + All files with an uncompressed size exceeding the threshold will be
>> + processed by the large file system. By default the threshold is
>> + defined in bytes. Add the suffix k, m, or g to change the unit.
>> +
>> +git-p4.largeFileCompressedThreshold::
>> + All files with a compressed size exceeding the threshold will be
>> + processed by the large file system. This option might slow down
>> + your clone/sync process. By default the threshold is defined in
>> + bytes. Add the suffix k, m, or g to change the unit.
>> +
>> +git-p4.pushLargeFiles::
>> + Boolean variable which defines if large files are automatically
>> + pushed to a server.
>> +
>> Submit variables
>> ~~~~~~~~~~~~~~~~
>> git-p4.detectRenames::
>> diff --git a/git-p4.py b/git-p4.py
>> index b465356..bfe71b5 100755
>> --- a/git-p4.py
>> +++ b/git-p4.py
>> @@ -22,6 +22,8 @@ import platform
>> import re
>> import shutil
>> import stat
>> +import zipfile
>> +import zlib
>>
>> try:
>> from subprocess import CalledProcessError
>> @@ -932,6 +934,111 @@ def wildcard_present(path):
>> m = re.search("[*#@%]", path)
>> return m is not None
>>
>> +class LargeFileSystem(object):
>> + """Base class for large file system support."""
>> +
>> + def __init__(self, writeToGitStream):
>> + self.largeFiles = set()
>> + self.writeToGitStream = writeToGitStream
>> +
>> + def generatePointer(self, cloneDestination, contentFile):
>> + """Return the content of a pointer file that is stored in Git instead of
>> + the actual content."""
>> + assert False, "Method 'generatePointer' required in " + self.__class__.__name__
>> +
>> + def pushFile(self, localLargeFile):
>> + """Push the actual content which is not stored in the Git repository to
>> + a server."""
>> + assert False, "Method 'pushFile' required in " + self.__class__.__name__
>> +
>> + def hasLargeFileExtension(self, relPath):
>> + return reduce(
>> + lambda a, b: a or b,
>> + [relPath.endswith('.' + e) for e in gitConfigList('git-p4.largeFileExtensions')],
>> + False
>> + )
>> +
>> + def generateTempFile(self, contents):
>> + contentFile = tempfile.NamedTemporaryFile(prefix='git-p4-large-file', delete=False)
>> + for d in contents:
>> + contentFile.write(d)
>> + contentFile.flush()
>> + contentFile.close()
>
> close() should flush() automatically I would have thought.Correct. SO thinks so, too https://stackoverflow.com/questions/2447143/does-close-imply-flush-in-python
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>
>> + return contentFile.name
>> +
>> + def exceedsLargeFileThreshold(self, relPath, contents):
>> + if gitConfigInt('git-p4.largeFileThreshold'):
>> + contentsSize = sum(len(d) for d in contents)
>> + if contentsSize > gitConfigInt('git-p4.largeFileThreshold'):
>> + return True
>> + if gitConfigInt('git-p4.largeFileCompressedThreshold'):
>> + contentsSize = sum(len(d) for d in contents)
>> + if contentsSize <= gitConfigInt('git-p4.largeFileCompressedThreshold'):
>> + return False
>> + contentTempFile = self.generateTempFile(contents)
>> + compressedContentFile = tempfile.NamedTemporaryFile(prefix='git-p4-large-file', delete=False)
>> + zf = zipfile.ZipFile(compressedContentFile.name, mode='w')
>> + zf.write(contentTempFile, compress_type=zipfile.ZIP_DEFLATED)
>> + zf.close()
>> + compressedContentsSize = zf.infolist()[0].compress_size
>> + os.remove(contentTempFile)
>> + os.remove(compressedContentFile.name)
>> + if compressedContentsSize > gitConfigInt('git-p4.largeFileCompressedThreshold'):
>> + return True
>> + return False
>> +
>> + def addLargeFile(self, relPath):
>> + self.largeFiles.add(relPath)
>> +
>> + def removeLargeFile(self, relPath):
>> + self.largeFiles.remove(relPath)
>> +
>> + def isLargeFile(self, relPath):
>> + return relPath in self.largeFiles
>> +
>> + def processContent(self, cloneDestination, git_mode, relPath, contents):
>> + """Processes the content of git fast import. This method decides if a
>> + file is stored in the large file system and handles all necessary
>> + steps."""
>> + if self.exceedsLargeFileThreshold(relPath, contents) or self.hasLargeFileExtension(relPath):
>> + contentTempFile = self.generateTempFile(contents)
>> + (git_mode, contents, localLargeFile) = self.generatePointer(cloneDestination, contentTempFile)
>> +
>> + # Move temp file to final location in large file system
>> + largeFileDir = os.path.dirname(localLargeFile)
>> + if not os.path.isdir(largeFileDir):
>> + os.makedirs(largeFileDir)
>> + shutil.move(contentTempFile, localLargeFile)
>> + self.addLargeFile(relPath)
>> + if gitConfigBool('git-p4.pushLargeFiles'):
>> + self.pushFile(localLargeFile)
>> + if verbose:
>> + sys.stderr.write("%s moved to large file system (%s)\n" % (relPath, localLargeFile))
>> + return (git_mode, contents)
>> +
>> +class MockLFS(LargeFileSystem):
>> + """Mock large file system for testing."""
>> +
>> + def generatePointer(self, cloneDestination, contentFile):
>> + """The pointer content is the original content prefixed with "pointer-".
>> + The local filename of the large file storage is derived from the file content.
>> + """
>> + with open(contentFile, 'r') as f:
>> + content = next(f)
>> + gitMode = '100644'
>> + pointerContents = 'pointer-' + content
>> + localLargeFile = os.path.join(cloneDestination, '.git', 'mock-storage', 'local', content[:-1])
>> + return (gitMode, pointerContents, localLargeFile)
>> +
>> + def pushFile(self, localLargeFile):
>> + """The remote filename of the large file storage is the same as the local
>> + one but in a different directory.
>> + """
>> + remotePath = os.path.join(os.path.dirname(localLargeFile), '..', 'remote')
>> + if not os.path.exists(remotePath):
>> + os.makedirs(remotePath)
>> + shutil.copyfile(localLargeFile, os.path.join(remotePath, os.path.basename(localLargeFile)))
>> +
>> class Command:
>> def __init__(self):
>> self.usage = "usage: %prog [options]"
>> @@ -1105,6 +1212,9 @@ class P4Submit(Command, P4UserMap):
>> self.p4HasMoveCommand = p4_has_move_command()
>> self.branch = None
>>
>> + if gitConfig('git-p4.largeFileSystem'):
>> + die("Large file system not supported for git-p4 submit command. Please remove it from config.")
>> +
>> def check(self):
>> if len(p4CmdList("opened ...")) > 0:
>> die("You have files opened with perforce! Close them before starting the sync.")
>> @@ -2057,6 +2167,12 @@ class P4Sync(Command, P4UserMap):
>> lambda git_mode, relPath, contents: self.writeToGitStream(git_mode, relPath, contents)
>> )
>>
>> + if gitConfig('git-p4.largeFileSystem'):
>> + largeFileSystemConstructor = globals()[gitConfig('git-p4.largeFileSystem')]
>> + self.largeFileSystem = largeFileSystemConstructor(
>> + lambda git_mode, relPath, contents: self.writeToGitStream(git_mode, relPath, contents)
>> + )
>> +
>> if gitConfig("git-p4.syncFromOrigin") == "false":
>> self.syncWithOrigin = False
>>
>> @@ -2176,6 +2292,13 @@ class P4Sync(Command, P4UserMap):
>>
>> return branches
>>
>> + def writeToGitStream(self, gitMode, relPath, contents):
>> + self.gitStream.write('M %s inline %s\n' % (gitMode, relPath))
>> + self.gitStream.write('data %d\n' % sum(len(d) for d in contents))
>> + for d in contents:
>> + self.gitStream.write(d)
>> + self.gitStream.write('\n')
>> +
>> # output one file from the P4 stream
>> # - helper for streamP4Files
>>
>> @@ -2246,17 +2369,10 @@ class P4Sync(Command, P4UserMap):
>> text = regexp.sub(r'$\1$', text)
>> contents = [ text ]
>>
>> - self.gitStream.write("M %s inline %s\n" % (git_mode, relPath))
>> + if self.largeFileSystem:
>> + (git_mode, contents) = self.largeFileSystem.processContent(self.cloneDestination, git_mode, relPath, contents)
>>
>> - # total length...
>> - length = 0
>> - for d in contents:
>> - length = length + len(d)
>> -
>> - self.gitStream.write("data %d\n" % length)
>> - for d in contents:
>> - self.gitStream.write(d)
>> - self.gitStream.write("\n")
>> + self.writeToGitStream(git_mode, relPath, contents)
>>
>> def streamOneP4Deletion(self, file):
>> relPath = self.stripRepoPath(file['path'], self.branchPrefixes)
>> @@ -2265,6 +2381,9 @@ class P4Sync(Command, P4UserMap):
>> sys.stdout.flush()
>> self.gitStream.write("D %s\n" % relPath)
>>
>> + if self.largeFileSystem and self.largeFileSystem.isLargeFile(relPath):
>> + self.largeFileSystem.removeLargeFile(relPath)
>> +
>> # handle another chunk of streaming data
>> def streamP4FilesCb(self, marshalled):
>>
>> diff --git a/t/t9823-git-p4-mock-lfs.sh b/t/t9823-git-p4-mock-lfs.sh
>> new file mode 100755
>> index 0000000..8582857
>> --- /dev/null
>> +++ b/t/t9823-git-p4-mock-lfs.sh
>> @@ -0,0 +1,96 @@
>> +#!/bin/sh
>> +
>> +test_description='Clone repositories and store files in Mock LFS'
>> +
>> +. ./lib-git-p4.sh
>> +
>> +test_file_in_mock () {
>> + FILE="$1"
> Missing &&
> Plus the next few linesAre they strictly necessary? I believe you can define variables all in “one line”. I found it like that in existing tests: https://github.com/git/git/blob/f4d9753a89bf04011c00e943d85211906e86a0f6/t/t9402-git-cvsserver-refs.sh#L18-L20
Nevertheless I will add them in the next role!
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>
>> + CONTENT="$2"
>> + LOCAL_STORAGE=".git/mock-storage/local/$CONTENT"
>> + SERVER_STORAGE=".git/mock-storage/remote/$CONTENT"
>> + echo "pointer-$CONTENT" >expect_pointer
>> + echo "$CONTENT" >expect_content
>> + test_path_is_file "$FILE" &&
>> + test_path_is_file "$LOCAL_STORAGE" &&
>> + test_path_is_file "$SERVER_STORAGE" &&
>> + test_cmp expect_pointer "$FILE" &&
>> + test_cmp expect_content "$LOCAL_STORAGE" &&
>> + test_cmp expect_content "$SERVER_STORAGE"
>> +}
>> +
>> +test_file_count_in_dir () {
>> + DIR="$1"
>> + EXPECTED_COUNT="$2"
>> + find "$DIR" -type f >actual
>> + test_line_count = $EXPECTED_COUNT actual
>> +}
>> +
>> +test_expect_success 'start p4d' '
>> + start_p4d
>> +'
>> +
>> +test_expect_success 'Create repo with binary files' '
>> + client_view "//depot/... //client/..." &&
>> + (
>> + cd "$cli" &&
>> +
>> + echo "content 1 txt 23 bytes" >file1.txt &&
>> + p4 add file1.txt &&
>> + echo "content 2-3 bin 25 bytes" >file2.dat &&
>> + p4 add file2.dat &&
>> + p4 submit -d "Add text and binary file" &&
>> +
>> + mkdir "path with spaces" &&
>> + echo "content 2-3 bin 25 bytes" >"path with spaces/file3.bin" &&
>
> Nice putting spaces in the path!I stumbled across this case in a production migration :-)
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>
>> + p4 add "path with spaces/file3.bin" &&
>> + p4 submit -d "Add another binary file with same content and spaces in path" &&
>> +
>> + echo "content 4 bin 26 bytes XX" >file4.bin &&
>> + p4 add file4.bin &&
>> + p4 submit -d "Add another binary file with different content"
>> + )
>> +'
>> +
>> +test_expect_success 'Store files in Mock based on size (>24 bytes)' '
>> + client_view "//depot/... //client/..." &&
>> + test_when_finished cleanup_git &&
>> + (
>> + cd "$git" &&
>> + git init . &&
>> + git config git-p4.useClientSpec true &&
>> + git config git-p4.largeFileSystem MockLFS &&
>> + git config git-p4.largeFileThreshold 24 &&
>> + git config git-p4.pushLargeFiles True &&
>> + git p4 clone --destination="$git" //depot@all &&
>> +
>> + test_file_in_mock file2.dat "content 2-3 bin 25 bytes" &&
>> + test_file_in_mock "path with spaces/file3.bin" "content 2-3 bin 25 bytes" &&
>> + test_file_in_mock file4.bin "content 4 bin 26 bytes XX" &&
>> +
>> + test_file_count_in_dir ".git/mock-storage/local" 2 &&
>> + test_file_count_in_dir ".git/mock-storage/remote" 2
>> + )
>> +'
>> +
>> +test_expect_success 'Run git p4 submit in repo configured with large file system' '
>> + client_view "//depot/... //client/..." &&
>> + test_when_finished cleanup_git &&
>> + (
>> + cd "$git" &&
>> + git init . &&
>> + git config git-p4.useClientSpec true &&
>> + git config git-p4.largeFileSystem MockLFS &&
>> + git config git-p4.largeFileThreshold 24 &&
>> + git config git-p4.pushLargeFiles True &&
>> + git p4 clone --destination="$git" //depot@all &&
>> +
>> + test_must_fail git p4 submit
>
> No test for deletion, does that matter?
OK, I will add one in the mock, too. I have a test for that in the “t9828-git-p4-lfs.sh” named “Remove file from repo and store files in LFS based on size (>24 bytes)”.
Thanks, Lars
larsxschneider@gmail.com
